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I'm sorry I haven't come around to make more pictures of that board, I have often very little time to sit down and work on something like this nowadays. I probably will a bit today or tomorrow though. Long weekend! Also will say a few things about EGA and that card.spankmeister posted:Working on my MSX today, pictures incoming! You don't really need a schottky in this case, a bog standard 1N4001(-004, 007 etc.) will do fine. Most of this RTC/SRAM circuity to keep settings or the time cuts off at around 2V and accepts anything between 2V and usually 5-6V. The higher the voltage, the more current the ICs will usually eat, for many people often ending up emptying the battery in a year or two. With the average CR2032 I would add an 1.2 kOhm Resistor in series to the Diode, assuming a voltage drop of 0,7V across the Diode at these conditions, so we can be sure the Battery will be fine for a while. As soon as a lithium coin cell drops below ~2.9V-2.8V it's basically empty anyways. EDIT: Woa many typos that's what I get for posting that while doing something else Police Automaton fucked around with this message at 14:20 on Feb 22, 2015 |
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Feb 22, 2015 13:16
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Thanks for the info. I actually had a different idea just now. What about a supercap? I think I have a 5v 1F thingy somewhere, should work fine. Dunno what the actual lifetime would be w.r.t. the self discharge of the thing, but at least they don't leak afaik.
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Feb 22, 2015 17:35
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spankmeister posted:Thanks for the info. If you're worried about that, a Lithium cell can't leak. They're completely dry. Maybe you are aware of this but I regularly run into people that think they aren't (or aren't all) because they had run ins with alkali-manganese (or if more expensive silver-oxide) coin cells from portable radios and such which can leak and cause quite the mess, but they're a wholly different format. If it's CR2032, it's Lithium. Here's a nice picture of a CR2032 that has been taken apart: http://upload.wikimedia.org/wikipedia/commons/6/69/CR2032_disassembled.jpg (Please don't take Lithium batteries apart if you don't know how, they can explode quite violently) See, nothing that can leak. If you did know, maybe it was informative for somebody else. A supercap would work, I can't tell you exactly how long it'd be sufficiently charged as that is obviously very circuit-dependent, but I wouldn't assume more than ~2 weeks at best. It depends how often the system is running, obviously. The practical thing about a supercap would be obviously that you'd never have to touch/open up the system to exchange the battery again in the foreseeable future, but if it's worth it? Maybe if the system is running regularly and you never want to open it again, which is valid. Losing time sometimes or when not using the system for a while might also just not be all that dramatic, seeing as how bad the clock drift is and how often it needs to be adjusted for anyways. If you don't need the clock at all, you might even just not replace the battery with anything. You'd just lose timestamps and such (if you don't set the clock every time you use the computer). Another alternative in the rechargeable department would be NiMh-Batteries, they have basically the same properties as NiCd batteries regarding recharge and can be used interchangeably in the charging circuits. They do leak too, so you could get one of these closeable battery compartments, mount it where it can't do any damage and then just run some wires. Then you'd have still the rechargeable battery function and a long lifetime when the system is off. What I have also seen sometimes as replacement in old computers and absolutely don't recommend is using rechargeable lithium batteries. Lithium batteries have a completely different charging curve and used in a circuit like this without modification, you'll just destroy them. They also just don't like being used the way they would be in this situation and would have a relatively short lifespan. As you can see there are many possibilities, what you wanna do depends on what seems the most practical. Police Automaton fucked around with this message at 18:27 on Feb 22, 2015 |
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Feb 22, 2015 18:21
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Police Automaton posted:If you're worried about that, a Lithium cell can't leak. They're completely dry. Maybe you are aware of this but I regularly run into people that think they aren't (or aren't all) because they had run ins with alkali-manganese (or if more expensive silver-oxide) coin cells from portable radios and such which can leak and cause quite the mess, but they're a wholly different format. If it's CR2032, it's Lithium. Here's a nice picture of a CR2032 that has been taken apart: http://upload.wikimedia.org/wikipedia/commons/6/69/CR2032_disassembled.jpg (Please don't take Lithium batteries apart if you don't know how, they can explode quite violently) See, nothing that can leak. If you did know, maybe it was informative for somebody else. Exploding lithium batteries can be fun if done on purpose and not by accident though.  quote:A supercap would work, I can't tell you exactly how long it'd be sufficiently charged as that is obviously very circuit-dependent, but I wouldn't assume more than ~2 weeks at best. It depends how often the system is running, obviously. The practical thing about a supercap would be obviously that you'd never have to touch/open up the system to exchange the battery again in the foreseeable future, but if it's worth it? Maybe if the system is running regularly and you never want to open it again, which is valid. Losing time sometimes or when not using the system for a while might also just not be all that dramatic, seeing as how bad the clock drift is and how often it needs to be adjusted for anyways. If you don't need the clock at all, you might even just not replace the battery with anything. You'd just lose timestamps and such (if you don't set the clock every time you use the computer). Once I want to use my machine again I tend to use it for a couple of days/weeks and then I don't for a long time usually. Supercap would mean having to set stuff once, but then it'll stay charged for the remainder of that period until the next time i want to use it. Coin cell means I might have to replace it in a couple of years. It's a bit of a wash. quote:Another alternative in the rechargeable department would be NiMh-Batteries, they have basically the same properties as NiCd batteries regarding recharge and can be used interchangeably in the charging circuits. They do leak too, so you could get one of these closeable battery compartments, mount it where it can't do any damage and then just run some wires. Then you'd have still the rechargeable battery function and a long lifetime when the system is off. quote:What I have also seen sometimes as replacement in old computers and absolutely don't recommend is using rechargeable lithium batteries. Lithium batteries have a completely different charging curve and used in a circuit like this without modification, you'll just destroy them. They also just don't like being used the way they would be in this situation and would have a relatively short lifespan.
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Feb 22, 2015 18:49
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Took my Mac IIci out of storage to check the battery. Turns out someone already put a lithium in there so it's good. Police Automaton you said those SMD capacitors go leaky as well? Might as well replace those then with some OS-CON caps or something.
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Feb 22, 2015 20:14
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quote:MSX battery Wait what?! MSX with a battery in too? :O Does someone have a list somewhere of all the computers I need to take to pieces to stop them killing themselves when I'm not looking? I was already surprised enough when the A500+ barfed over its insides.
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Feb 22, 2015 23:42
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I have to say I really hate how many old computer designs decided on a built in sorta-rechargeable battery to hold the bios settings/real time clock, versus just expecting people to pop in a CR2032 every decade or so.
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Feb 22, 2015 23:45
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Nintendo Kid posted:I have to say I really hate how many old computer designs decided on a built in sorta-rechargeable battery to hold the bios settings/real time clock, versus just expecting people to pop in a CR2032 every decade or so. Apple did put a clock battery compartment on the Mac Plus, though strangely not on much else. Before the ATX standard not many computers had any sort of standby power, so a non-rechargeable coin cell would drain even when the system was plugged in and there would have to be some way to replace it without opening the case and voiding the warranty.
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Feb 23, 2015 01:43
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spankmeister posted:Took my Mac IIci out of storage to check the battery. Turns out someone already put a lithium in there so it's good. Yes, old SMD caps leak, too. People experiment with all kinds of caps to replace them, tantalum, ceramics, aluminium-polymer, etc.. With varying degrees of success. With the A600 at least I found that the very low ESR of ceramic caps can cause problems for the CXA1145 at the VREF input, which in turn causes the composite output of that machine to flicker. It can always be a problem to replace one type of capacitor with another. All in all, modern, brand-name electrolytic caps are fine to use. There are many theories over the years why old SMD caps are so prone to leaking, and they probably all have their truths to them. Fact is, the early SMD caps of many electronic devices started leaking really quickly, with people experiencing this problem already in and around 2000, when the affected systems were around 10 years old. I've yet to see leaky SMD caps of a device of the latter half of the 90s. So, even if caps got a bad name with the retro computing people, it's pretty sensible to assume that modern, high-quality electrolytic caps will not suffer from the leakage problem this dramatically and are fine to use. They do have a shelf life though and will eventually stop performing to their specs. That's true for polymer caps, too. I found the latter usually too large in the required voltage ranges in practice to fit on the SMD pads of these old systems in every case. legooolas posted:Wait what?! MSX with a battery in too? :O It's safe to assume that everything that has a clock or a way to save settings that remain when the machine is powered off has a battery. The problem with these Rechargeable NiCd/NiMh (and yes even lithium) batteries is that they most of all, don't like getting completely discharged and especially in case of NiMh/NiCd not used/charged for long periods of time. This will damage them. The idea in itself isn't terrible. Usable lithium batteries weren't really around until the mid-80s and the lithium coin cell specifically underwent lots of development right into the 90s. Rechargeable lithium Ion polymer batteries you find in modern hand held devices were a development of the late 90s. It's overseen in favor of the much more interesting computer revolution of that time period, but there was also a lot of development in the battery field which was necessary to make modern handheld devices even possible.
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Feb 23, 2015 04:00
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you know, I think my Mac's caps have gone bad because I was playing with it today and I booted it up a couple of times and ran just fine but after shutting it down the last time it won't turn on no matter what I try. some of the caps are part of a power on/reset circuit that's supposed to apply a 5v voltage to the psu for it to turn on. either that or the psu is faulty, I can't really test it because you can't just short 2 pins like on an atx supply to start it.
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Feb 24, 2015 01:08
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Some 68k Macs refuse to boot without/with a dead PRAM-Battery. Also, I remember you said somebody already put a lithium battery in there. At least the later 68k Macs as far as I am aware all used these small, half-size AA lithium cells by default. Never run these power supplies without a consumer, it'll destroy them. That all being said, I have a Performa 475 here (really love all the mac 68k cases, but that has to be my favorite design) and there the power supply filter caps were on it's last legs too. Even the switch was faulty. They are an easy fix though. Naturally, the SMD-Caps of the board were all in the process of leaking, I'd assume the same would be the case for you.
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Feb 24, 2015 13:07
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After leaving it alone for a day or so it booted right up again. After running it for an hour or so and turning it off, it wouldn't boot anymore. I ordered a new PRAM battery, a real 1/2AA 3.6v one and not the 3v CR2 that's in there right now. I should try booting it without the battery installed to see if it'll boot at all. So a marginal PRAM battery miiight cause that but I don't think so because it also doesn't do the chime anymore (which it did a couple of days ago) and that's indicative of bad caps as well. I guess the caps were near death and applying full voltage after being in storage for a couple of years killed them. My caps should arive today, together with a CR2032 holder for my MSX so it's soldering time tonight.  I sure hope I can get it working reliably again because else the cache card I ordered will be useless.
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Feb 26, 2015 10:54
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My first real computer that I can remember as a kid was a Performa 5X00. I hated it as a kid (due to the problem where the volume would take forever to go down and my parents would be screaming at me to turn the computer down), but my dad remembers it as one of the best computers he ever had. I mostly remember that it had an insane number of indie games and it was the smoothest computer to play C&C on. We changed to Windows when OSX was released and the 5X00 wasn't compatible. I think it's still in the shed, I'll have to take a look.
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Feb 26, 2015 13:09
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I always (even as never ever being close to the old Macs back when they were still new) thought that the Macs generally have an interesting software collection from kind of a "looking back" perspective. Lots of hidden gems there. Most of the PowerPC and 68k Macs at least here in germany you can get for next to nothing, at least as it was the case about a year or two ago. If it's still like that, who knows with this market. I consider it kind of funny that the Amigas are worth so much money on average nowadays while you can get so much cheap old Mac crap nobody cares about, considering that the Mac computers are a lot better quality wise. Especially keyboard Amigas, are - let's face it - cheap crap from a manufacturing perspective, as are many of the highly sought after 3rd party expansions for them.spankmeister posted:I guess the caps were near death and applying full voltage after being in storage for a couple of years killed them. Not exactly what you said but I'll bring it up still because I hear similar things often. That caps need to be pre-conditioned after a bit of storage is an old wives tale that stuck around because it was true for old capacitors (I'm thinking 70s and pre-70s) anything "modern" (80s and on) is usually relatively chemically inert and has a very long shelf life, even when not in use. No Voltage application for a few years (2-3) is usually not a problem at all and in fact, much longer usually isn't either and I'd trust new electrolytic caps to even last for ten or more years without problem and without voltage applied. You should replace the capacitors even if the machine works with a new battery, or you'll eventually regret it. I can repeat only time and time again, the old SMD electrolytic capacitors are not safe to leave in the systems anymore in 2015 and will eventually cause damage, if they haven't already. There are no ifs or buts. Modern SMD electrolytic caps are perfectly fine to use and a lot more reliable, when soldered correctly. SMD soldering is not harder than THT soldering, just different. Sadly I had to travel somewhere and will probably not be at home for another two or three weeks. That's why there were no further updates on the repair of the 8088. I already worked out a solution for adapting EGA to the XRGB Mini and will explain that some more when I find the time. I also managed to take a few pics of the 8088 Mainboard before I left and will post them soon. Before I left I spent some time cleaning up that EGA-Card I got for two bucks off eBay. It even had some rust, is covered in scratch marks and a pin from a pinheader broke off. I'll get it up and running fine though. I'll talk about that card some more in a bit because I was able to locate the BIOS for it on the Internet and made an interesting observation you come across often with the contents of EPROMs which might be interesting background information for some of you. It will also be a good time to cover some electronics basics in that post so the explanation with the EGA and the Mini later on will make more sense for some of you. You see, that card is by no means an collectors item and I think most people interested in buying it would have just robbed the rather rare RAM-ICs off it and throw the rest in the trash, but I think the effort is always worth it. Old computer maintenance becomes more and more demanding with passing years as time becomes a bigger and bigger enemy. More and more people seem to be interested in them, but the knowledge still sort of just "dies off". This kind of leads to a hobby were people treat these machines either as untouchable collectors' items that just have to stay in mint condition (even if they rot from the inside out) with weird, almost superstitious beliefs about their capabilities to another group of people that treats them like normal consumer items that get replaced and thrown in the trash when they break or don't look nice anymore, be it through old age (much more rare than you think) or wrong handling. (much more common than you think) It's a pity that lots of these basically irreplaceable (as nobody manufactures them anymore) electronics and testaments of technological evultion end up in the trash because people in general just don't care, making them more rare and also expensive for interested parties. Eventually, you'll have that collectors item here and there for a crazy price on eBay and everything else will be more or less gone. It already sort of happened with some hardware. It's a pity. With my posts here I hope I can infect some of you to spend a bit more time and money on maintenance on the old 'puter you might have. Police Automaton fucked around with this message at 15:11 on Feb 26, 2015 |
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Feb 26, 2015 15:07
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Can I ask, what do you do with this hardware? I had an Amiga 500 and loved the thing, but more recently a coworker also had one and was all excited about getting to going and connecting it to the net and displaying a webpage on it. It all seemed rather strange to me, but the Unix guys can be like that.
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Feb 26, 2015 15:45
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Police Automaton posted:Not exactly what you said but I'll bring it up still because I hear similar things often. That caps need to be pre-conditioned after a bit of storage is an old wives tale that stuck around because it was true for old capacitors (I'm thinking 70s and pre-70s) anything "modern" (80s and on) is usually relatively chemically inert and has a very long shelf life, even when not in use. No Voltage application for a few years (2-3) is usually not a problem at all and in fact, much longer usually isn't either and I'd trust new electrolytic caps to even last for ten or more years without problem and without voltage applied. You should replace the capacitors even if the machine works with a new battery, or you'll eventually regret it. I can repeat only time and time again, the old SMD electrolytic capacitors are not safe to leave in the systems anymore in 2015 and will eventually cause damage, if they haven't already. There are no ifs or buts. Modern SMD electrolytic caps are perfectly fine to use and a lot more reliable, when soldered correctly. SMD soldering is not harder than THT soldering, just different. Yeah I'm replacing the caps, don't worry. 
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Feb 26, 2015 17:08
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Tony Montana posted:Can I ask, what do you do with this hardware? That's too easy mode. What's fun is managing to do it with an Apple IIgs or C64.
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Feb 26, 2015 17:54
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Tony Montana posted:Can I ask, what do you do with this hardware? Cleaning, building, repairing, configuring and generally getting it to work is the fun part. Once it runs fine it's time to stop caring about it and move on to the next project.
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Feb 27, 2015 08:14
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I've been doing research into getting into the E-Waste recycling business, and I would put forth an effort to have anything old, valuable, or just interesting saved from the landfill, or being shredded.
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Mar 1, 2015 03:56
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I don't think the Mac IIci is one of the machines that absolutely requires a PRAM battery. You should be good to try removing it altogether and booting. It probably is caps. There's old wives tale advice saying to leave the machine plugged in for a bit before booting but that's probably just a workaround for dodgy caps.
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Mar 1, 2015 17:34
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I was abroad without internet so I couldn't post about it but I replaced the caps and it boots like a champ now with a solid "ding" I also tried it with the battery removed altogether just to try it out and it works fine.
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Mar 1, 2015 17:38
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Tony Montana posted:Can I ask, what do you do with this hardware? evobatman posted:Cleaning, building, repairing, configuring and generally getting it to work is the fun part. Once it runs fine it's time to stop caring about it and move on to the next project. The trick is to use them to do things you want or need to do, because you like using old hardware to do it. It's fun to restore a rainwater damaged old machine and upgrade it, but when that's all you know how to do, it just shows your own personal limitations. These machines all have huge software libraries, you can do almost anything on them. Probably the worst for this are the 68k Mac people. At least when Amiga nerds spend thousands on building extremely upgraded tower conversions, they'll occasionally turn it on and play an MP3 to impress themselves. Mac people seem to just fill garages with stacks of computer towers they don't know what to do with. Best to stick to one or two machines, get some nice accessories, some software you think is interesting, and some period magazines or whatever, set them up in a comfortable area, and just do stuff with them. I personally still use a G3 mac running OS9 for email/word/excel/photoshop/illustrator etc because I'm used to it and ribbon toolbars infuriate me. I'm considering writing a twitter client for it, because newer machines aren't any better at any of this sort of work. I'm getting a bunch of stuff for my Atari STE this week. A broadcast monitor and a highres mono one. Time to start building adapter cables so I can HorseLord fucked around with this message at 22:07 on Mar 1, 2015 |
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Mar 1, 2015 22:02
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Nah, the Amiga-nerds hoard also stuff like crazy they're never going to use. That with the generally lower production runs of Amiga hardware is kind of responsible for the prices of the Hardware. It's always disheartening to see people who sit on rare hardware (sometimes not even necessarily worth much) and do absolutely nothing interesting with it, let alone know much about it. But the Amiga community is probably one of the worst communities there is regarding being absolutely clueless and having too much money. Also people somehow always feel they need spares in case their stuff somehow magically breaks. As long as stuff is good maintained, it's very robust. I'd even say death cause No 1 for old hardware is probably "incorrect handling". By far. (besides "getting recycled") I have all my old Systems in reach and everything is connected via KVM-Switch to my Keyboard/Mouse/Screen, up to and including my i7. If you don't use them, what's the point owning them? You can do a lot with old systems, but like with so many things in life - it really depends on what you want to do. There is still very usable software for these old systems even in the productivity department and just because there wasn't a software update in the last 10-20 years often doesn't mean the software somehow turned bad. I do lots of pixel stuff and writing on my A2000 and it's just fine for that and feels more responsive and easier to use than every recent windows machine I was confronted with. I even got my old needle printer hooked up to the parallel port. A black ink band for it costs about five bucks and lasts an eternity compared to whatever modern printer you can come up with. It's also a lot easier to set up and use. (300 MB printer drivers? No thanks) For what little printing I do, I couldn't have anything better. Also I love the sounds it makes. -- While I was here, somebody gave me a Mac Mini G4. I guess it's barely "retro" but believe it or not, it's the first PowerPC thing I own. There's a lot of interesting software stuff to explore in the Mac world I never really could take a look at. I have no clue how backwards compatible things tend to be, but I guess "rather good". Should be interesting at any rate.
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Mar 2, 2015 15:24
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Police Automaton posted:While I was here, somebody gave me a Mac Mini G4. I guess it's barely "retro" but believe it or not, it's the first PowerPC thing I own. There's a lot of interesting software stuff to explore in the Mac world I never really could take a look at. I have no clue how backwards compatible things tend to be, but I guess "rather good". Should be interesting at any rate. You can run OS X up to version 10.5 "Leopard", or classic Mac OS 9 (or dual-boot, of course). However, keep in mind that a lot of OS X software is no longer compatible with PowerPC, including the latest versions of Firefox etc. Personally, I would probably just put Linux on it, but I'm boring like that.
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Mar 3, 2015 13:45
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KozmoNaut posted:You can run OS X up to version 10.5 "Leopard", or classic Mac OS 9 (or dual-boot, of course). You can use the Classic environment to run most OS9 programs if you run. 10.4(tiger), but you can't boot to it with a Mac Mini.  IIRC, the last Mac that will boot to OS9 is the Mirrored Drive Door series of G4 towers, and you need a special version of 9.2 to do it - it was a giant PITA to set mine up that way. Personally, I think running OS10.4 Tiger and the TenFourFox browser gives the best user experience on the G4 Mini compared to Leopard or Linux - probably due to its 1gig max memory capacity - but that's JMO.
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Mar 4, 2015 03:39
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Thanks for the advice. I don't really have any interest to turn that thing into an everyday machine +workable browser, though. I have an i7 for that. The most interesting thing for me would be to use it for running old PPC-Games/Apps, as I have nothing else that can do that. Comedy Option: MorphOS. (it's sort of a rewritten AmigaOS for modern PPCs in case you never heard of it, which wouldn't suprise me as I think it only sold around ~2000 copies) It costs around 79 € to use fully on an G4 and the serial you get is only for one machine and non-transferable. Very good measures to make sure your OS stays dead and nobody ever will use it. It's binary compatible to old Amiga applications though, as long as they don't want to directly bang the chipset (which is nearly all of them) in which case it runs them in some kind of E-UAE. Utter nonsense these days as you could run WinUAE on any old PC for free with performance where only the sky is the limit. I don't think they're greedy regarding the fee though. They're just a bunch of stubborn, aging nerds which actually think their OS is worth that kind of money. I guess you can also apply that to their userbase. What they have been smoking in a time where you can get something like Linux and lots and lots of programs for it for free eludes me, especially considering that nobody really *needs* the legacy compatibility. I've been running an Pentium III with 700 Mhz (running FreeBSD) and 768 MB ECC (!!) RAM as Fileserver in the last weeks, it eats around 32W in idle (it's headless, doesn't even have a graphics card) and is pretty much fast enough for everything I throw at it. It doesn't run 24/7, but wakes up on demand. Not really the most efficent choice of server these days, but I really feel fond of the Pentium 3. I wanted to do this with an Rasberry Pi (when that hype was going) but found the 512 MB Pi I had too painfully slow to do really anything with it even though it was neat to run a *nix on a RISC CPU once again (yes I know, smartphones and tablets.. just not the same though). I gotta admit, the small ARM SBCs are unbeatable in the performance/Watts/$$$ ratio you get from them, but still. They're not massively impressive either. I don't get why the Pi got compared to the C64 so goddamn much. The C64 was a very decent computer for it's time, especially considering the price tag. Can't really say that about the Pi. I guess both have sort of a User Port and lack a hardware clock but you know. I'd like to have a system I can run 24/7 and ssh/telnet (via serial) into to run my emacs stuff (yes I'm a dinosaur) and assorted other console apps from my old computers but I don't really want to drop much money on that. It'd be cool to do that with a PPC even though without googling and measuring I highly doubt it will be more energy efficient than the P3. Maybe I should look into the small ARMs (pun intended) again, maybe they improved a little. Power consumption is sort of an issue as that's a very expensive thing in Germany.
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Mar 4, 2015 12:39
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I don't think the G4 Mini could compete with an ARM machine in terms of power consumption, but it's pretty drat miserly compared to most machines - mine barely gets warm running Classic OS stuff on an emulator, and the power supply is.only 85 watts.
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Mar 4, 2015 14:34
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I googled and on Apples official page itself it states a power consumption of 32W while idle, which is funny considering that this is exactly what my P3 consumes. I guess it's about what I guessed. I might take another look at ARM SBCs even though I somehow doubt they improved much performance-wise.
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Mar 4, 2015 16:49
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Your best option for a very low power consumption, especially at idle, machine is probably an Intel NUC or a clone. The Intel NUCs will idle at around 15-18 watts and peak power consumption is about 26-30 watts. They come with full recent Core i3 and Core i5 processors too, so it's not like you're losing out on performance either.
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Mar 4, 2015 19:20
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Don't really feel like spending that kind of money for something that's just "playing around" at best, and a core ix is kind of too much already. I would have probably been happy with the Pi if it was just that little bit faster and had just that little bit memory more. It's kinda funny how computing power became so cheap nowadays that it's barely worth it to come up with creative solutions to your small-scale problems. Only a few years ago some old computer made a great server, now there are all these highly specialized solutions and using an old computer that way often is simply not worth it. Well enough about my computing problems, maybe I'll take that question over to the Rasberry Pi Thread. (Somehow I still want to give the ARMs a chance) Next post from me here will contain old computer crap again.
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Mar 5, 2015 01:23
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Have you seen the recently released Raspberry Pi 2? It's bumped up to a quad core ARM chip at 900mhz, with 1GB RAM. Same price and form factor as the Raspberry Pi B+.
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Mar 5, 2015 17:44
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n0tqu1tesane posted:Have you seen the recently released Raspberry Pi 2? It's bumped up to a quad core ARM chip at 900mhz, with 1GB RAM. Same price and form factor as the Raspberry Pi B+. Yes, I also looked at the ODroid C1. I think the biggest problem with the latter is the eventual drop of software support, or so I'd wager. For people who don't know about it yet, Dave Haynie, chief engineer of Commodore and Dude responsible for lots of Amiga crap is auctioning off quite a few things on eBay where you can find him under the seller name of hazydave. Amongst the things are also a few prototype things.(The Gemini Prototype Board just went up).He's a nice guy I had contact here and there with, always very willing to share a story or two. Most interesting thing in his auction currently are the Buster specs which will be auctioned off in a few hours. Luckily he was agreeable on scanning them in before sending them off, so they might be used for a Buster Rev 12 eventually when somebody is ready to pick up the work. Well, at least they will end up in the public domain anyways. (For people not in the know, the Buster chip which managed the Z3-Bus was notoriously buggy and unfinished (even in it's latest revision, Rev 11) which was mostly the fault of the Chip managing the Bus basically being developed by Haynie alone and never really getting finished because of the management troubles at Commodore and also technological constraints at the time. Zorro III can be seen as Commodores answer to PCI) Most interesting prototype stuff he sells off is too rich for my blood and will probably end up in some collectors basement without ever being properly photographed and documented. It really is a pity.
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Mar 8, 2015 22:19
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So after the capacitor replacement on my mac it worked great, for a while. I had it plugged in, not even on, and I was in another room when I heard a pop. I didn't think too much of it until about 15 minutes later when i smelled a very familiar smell. I came to the room with the mac in it only to find it was filled with thin veils of smoke. Turns out that his had happened:  (click for huge)  But, I just fixed it by replacing all the film caps on the mains side of the power supply and it's now working again, yay! I got all the proper X and Y rated caps for it, some of them were different pitch so I had to improvise slightly but nothing spectacular. spankmeister fucked around with this message at 20:00 on Mar 11, 2015 |
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Mar 11, 2015 19:57
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BTW I promised some pics of my MSX so here they are: The most interesting about this is the construction IMHO. For one the single layer PCB with a whole bunch of wire jumpers, and the way the QFP packages are suspended in the middle of the board.                  
spankmeister fucked around with this message at 23:05 on Mar 11, 2015 |
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Mar 11, 2015 20:20
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spankmeister, could you please timg those pictures? Thank you. And yes, the RFI suppression caps catching on fire even when the computer isn't running and just connected to mains is a pretty common thing to happen with age. They are always "powered" when the power supply is connected to the mains and that's how it has to be. That it burns up like this is actually a safety feature, it shorting out could prove fatal for the user. I always just replace them when I replace the caps in the power supply, as these caps age in the way they are used too. Sometimes they're directly integrated into the Mains connector, then you have to replace the entire mains connector. But totally worth it when you are already doing maintenance. The power supply works without these caps too, but at least the Y-Capacitor part working properly is important for your safety. Don't ever run a power supply without it. Also always replace with properly rated parts, they are not like any old film capacitor. Interesting (albeit very cheap) board design. I like the silkscreen markings for the different regions of the board for maintenance. Nice little touch. Is that NiCd battery new? I wouldn't use NiCd anymore, better use NiMh if you absolutely have to use a rechargeable battery like this. It's still toxic but less so. If it's still the original battery, better remove. I'm pretty sure it's past it's prime. These old EPROMs and their high programming voltage. Here's a little neat trick: Burn a 27C256 with the programming voltage of a 27256 on accident and watch it glow out of the window. Only works once, though! I assume they cut out part of the PCB over the QFP chips for cooling. Sometimes you see such configurations with a heatsink attached to the back of the IC. Works pretty well.
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Mar 11, 2015 22:56
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Police Automaton posted:spankmeister, could you please timg those pictures? Thank you. Are you still viewing SA on your Amiga or something? quote:And yes, the RFI suppression caps catching on fire even when the computer isn't running and just connected to mains is a pretty common thing to happen with age. They are always "powered" when the power supply is connected to the mains and that's how it has to be. That it burns up like this is actually a safety feature, it shorting out could prove fatal for the user. I always just replace them when I replace the caps in the power supply, as these caps age in the way they are used too. Sometimes they're directly integrated into the Mains connector, then you have to replace the entire mains connector. But totally worth it when you are already doing maintenance. The power supply works without these caps too, but at least the Y-Capacitor part working properly is important for your safety. Don't ever run a power supply without it. Also always replace with properly rated parts, they are not like any old film capacitor. Yes I know which is why I ordered the correct X2 and Y2 rated capacitors. Very important. quote:Interesting (albeit very cheap) board design. I like the silkscreen markings for the different regions of the board for maintenance. Nice little touch. Is that NiCd battery new? I wouldn't use NiCd anymore, better use NiMh if you absolutely have to use a rechargeable battery like this. It's still toxic but less so. If it's still the original battery, better remove. I'm pretty sure it's past it's prime. This is, as far as I know, the original battery. I've since replaced it with this: quote:These old EPROMs and their high programming voltage. Here's a little neat trick: Burn a 27C256 with the programming voltage of a 27256 on accident and watch it glow out of the window. Only works once, though!
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Mar 11, 2015 23:23
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spankmeister posted:I used the 800x600 preview instead of the 1024x768 that imgur gives, happy now? No an old tablet, so even less useful for computing. I might be a dinosaur but I really hate tablets and have no idea what people find in these things. And now Apple markets Casio clocks ?! At any rate, I'm glad when I am back home, and then I have a few pictures and also a bit more to say again. Same person who gave me the G4 also now gave me a bunch of old graphics cards, one Hercules and two big-rear end ones. One a TIGA-based graphics card (still in sort of an nondescript OEM-Box and likely never used) the other an original IBM CGA card. spankmeister posted:Yes I know which is why I ordered the correct X2 and Y2 rated capacitors. Very important. I gotta say, from how much I loved the design of the Performa 475 I have, I was equally as much disappointed by the power supply. It really took the backseat in the design of the case size-wise. (today this wouldn't be as much as a problem, early 90s it was not that easy to make a small power supply which is also powerful and doesn't generate lots of heat) But it also was just a bit shoddily put together. The mains wires were directly soldered to the switch and connector (normally cables where you expect to have a lot of watts going you don't want to directly solder so they don't draw tin, get brittle and develop cracks) the cables were sort of crammed in there. Little plastic pieces here and there to isolate parts from other parts. Yeah no. I've seen a lot better. Then again, it's not a very powerful supply at 36 Watts and you don't have a lot of energy in there to begin with. I've seen worse too. The worst crime in power supplies I've seen were the mid- late 90s power supplies. That was a time where computers still were very expensive but got obsolete in 6 months and people just wanted to save as many bucks as they could were they could. Nobody cared about quality power supplies then either. I have one XIlence (I think they are still around) early ATX power supply somewhere at home I would consider downright dangerous by design. How that thing passed any kind of safety test is beyond me. After those shoddy power supplies people start to care about energy efficiency and such more and more and you started seeing them less, although I'm perfectly sure you can still get new noname piece-of-crap ATX power supplies today. spankmeister posted:It looks brand new doesn't it? Sometimes these old Batteries just sort of get suspended in Ttme and look perfectly fine. Normally NiCd/NiMh batteries tend not to leak when they get recharged and used regularly, which could be a factor. They just lose their capacity and get increasingly more hot when used/charged. spankmeister posted:My programming software didn't have the exact same one but I just picked the closest equivalent and set the voltage manually. MiniPro should have 27256. It's not important to have the same manufacturer with the default EPROM types set in the software, they're all the same anyways and get programmed the same way, at least by these cheap programmers. I have a Minipro too. Pretty unbeatable for that price range IMHO.
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Mar 12, 2015 11:55
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Police Automaton posted:I have a Minipro too. Pretty unbeatable for that price range IMHO.
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Mar 12, 2015 12:52
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Sweevo posted:There's a firmware hack for the -CS version which enables the ICSP port, turning it into the -A version, so you can program PICs and AVRs in-circuit. You just need to add a 6-pin header to the board. I heard about this, didn't think it was that straightforward, Interesting! I'll be back home at the end of this week. The other day I thought about a very specific retro computer that sits at my home and diligently woke up when I needed anything from it while i was on the road: my i7 860. I think I have that computer as my main PC for 6 years now? Every few months I think about upgrading, look at current mainboards and Intel's current offerings (who still thinks about AMD, although I do think Intel really needs a serious competitor or else eventually we all will suffer) and don't really see the sense in spending several hundred dollars in buying a machine that'd improve my computing experience (outside of running synthetic benchmarks) by having things compile a minute or two faster and unpack that .zip a few seconds earlier. I wanted to upgrade my current graphics card a few months ago, but again practically thinking what I'd possibly needed a new graphics card for stopped me. I do most of my stuff in Linux, sometimes I hop over to windows to play a little. Still I can set every game I play to very high/ultra, lock the framerate at 30 and have an incredible smooth gaming experience where the loud fans of my current graphics card don't even really spin up. It's amazing what milage I got (and continue to get) out of this computer. The old and allmighty A2000 back then wasn't relevant nearly half as long. Hell, when you think about it, most of this retro computing hobby is about computers that sometimes were relevant a year or two at best till they got seriously outpaced by better designs. Of course there's also faster PCIe slots etc. out there now but again, not a thing that'd have really an impact on my computer experience. A few weeks ago I overclocked the ol' i7, just to see how far I could take it on stock voltages. I got stable operation out of it at about 3,4 ghz which is quite an edge faster than stock speeds. You know what I did? Set it back to stock speed and undervolted it instead, because I couldn't think of an use for that additional performance and saving some power/bringing down the heat seemed more sensible. Like most people, I'll just wait what for what Skylake brings and maybe then consider an upgrade. I guess soon we'll see the end of Moore's law.I'm even at a point I was never with my current Desktop PC: Really having to do some maintenance - which means: Cleaning the case, refreshing some thermal paste and looking at the power supply. Maybe looking into buying a new hard drive. Power supplies age and 6 years is kind of a long time for such an high-powered power supply. I'll also be replacing the cheap fans that came with the expensive case and are kind of loud now. Here's a hint for you: If it's a quality manufacturer (ebm papst etc.) you can buy fans used and really make a bargain on it. I got a dozen very silent and high quality papst fans for ten euros (which is the price of one of these fans new) because they were used and a little dusty. Most people only know all these xxxtreme gamerz fans with LEDs and somesuch which fail after two years so people are usually reluctant to buy fans used, which means you can often get them really, really cheap. Quality fans don't just fail after a few years and will usually go on for ten years and more without a problem. Consult the datasheets. I say this because often with old computers, you want to replace at least the fan in the power supply because they get annoyingly loud. (in fact, they probably have always been loud. Fan technology really improved in the last 10-15 years) It still often is that way with fans that you can either have a silent fan or a fan with a high air flow, and usually not both. This becomes more true the smaller the fan is. You should always try to find out the specs of the fan you are replacing. People often go for the silent fans if they replace their fans in old computers thinking a modern, silent fan is always better and not rarely replace them with fans that are seriously underpowered. Always consider that in many old computer case designs, there usually was only a fan in the power supply and the thought for that fan was to air the entire computer case, so a fan that's barely cooling the power supply is not cutting it in this case. Some fans haphazardly added inside the case to move the air around aren't either. You want to get that warm air out of the case, even if slowly. In the same vein, it's often smarter to run the computer case closed, components can actually run hotter if you remove the case. I always said I will talk more about ATX power supplies and how they are bad for old computers and I will do that now. My problem is that I was not sure how to approach the subject the easiest, especially since I don't really have any good advice for the average user on what to do. I'll put everything in as simple words as possible, so you might already know much of this stuff, and I might not mention something or other but bear with me. I might also repeat myself. You see, computer power supplies heavily evolved since the 90s, and the way an old computer does it's power stuff is vastly different on how my i7 does it. The age of computers we are talking about here usually means most of the circuity runs on +5V, with an average tolerance of 10%. (4,75V to 5,25V) Consumption usually is fairly low, in the case of the 68000 for example around 1 Watt. (high compared to the computing power you are getting and for example what such a modern ARM SoC needs, but that's neither here nor there) While the power consumption of complex ICs always fluctuates somewhat depending on what the IC is doing exactly, usually these fluctuations are not dramatic and these old chips don't know any advanced power saving measures and don't really need them either, so the power draw of the computer is pretty constant from the moment of turning it on to the moment of turning it off and no matter what you do with it. This all leads to an often very simplistic power layout regarding the Mainboard. A bunch of ICs that draw power, a power supply that supplies lots of Amps on it's +5V rail (hopefully with low ripple) because they are needed there, and a few caps here and there to stabilize everything and make always sure the power is there when it's needed. Pretty simple. (not all that simple in fact, making a PCB layout regarding power is a science for itself and often wasn't even very well understood by the engineers back then - today the understanding is better) Then you have usually +12V for the mechanic stuff (hard drives, old disk drives etc.) and some low-powered negative voltages (-5V, -12V) for analog magic, like opamps in sound circuitry, ancient internal modems and some such. That's your average AT-Power supply and while many non-PC systems had different power supply pinouts and maybe additional functionality in the power supply, they pretty much worked the same way and satisfied the same needs. Later on in the Pentium era we get ATX (which on some pentium boards is optional, you can either use AT or ATX. I have some boards like that at home) which as biggest change added the 3.3V power rail because with heightened integration and smaller die structures we saw 3.3V logic (which often still was 5V compatible on the I/O Pins, but not the power supply pins, like all late 486-type and early Pentium I CPUs, or the Motorola 68060) but still early ATX PCs pretty much work the same way. The infrastructure does get a bit more complex as things as the CPU can have heightened demands on the power supply but usually it's still not all that complicated. Modern computers are vastly different from this. Here through the magic of highly efficient DC to DC power conversion we see lots of voltages generated on demand where they are needed, close to the ICs and circuity that need it. While the power infrastructure in some old 486 mainly consists of a bunch of caps dotted around the mainboard, in my i7 basically more than half of the mainboard is taken up just by the power infrastructure circuity. The reason for this is that with the tiny structures you see on the dies nowadays, the demands in the voltages being stable are very, very high and the tolerances for any instability and ripple very very low. Big fluctuations here can actually physically damage ICs quite easily so everything just has to be (nearly) perfect. Generating the voltages locally (lets call it point of load regulation, because that's what it's called) makes it a lot easier to guarantee that things will be stable, even if the power needed fluctuates wildly. Depending on what I do with my modern computer, the amount of Watts consumed by the mainboard and connected components can easily double and triple in less than a second. Without point of load regulation, it would be pretty much physically impossible to keep the supply to the ICs stable and "noise-free". Especially in this regard we have come a massively long way technologically in the last 15 to 20 years. Even if you could bring back an modern i7 and it's chipset, memory and such somehow back in time to 1997, it would be veeeeeeeeeery hard to design a working mainboard around it with the technology at hand. I'm not sure it could be done realistically. IBM actually was a pioneer in this regard and also already had the idea to locally generate all voltages that are needed and only have the power supply generate one voltage in the mid 90s, but it didn't really go anywhere and it took a bit for that idea to take off (and the technology to get to point where this would be effective). So with that in mind, the design of a modern power supply is vastly different too. Most of the magic happens around the +12V of the supply, which usually is taken to generate the voltages you need locally. The power supplies are built around being very powerful on the +12V rail and to make sure that doubling or tripling the demand on that +12V rail works without the voltage getting unstable. (not that easy to pull off) This is also usually where power supplies fail first, resulting in the commonly known failure that the computer works fine usually, but crashes when some graphics intensive game is played, as the power supply can't keep up with the demand when the graphics card kicks into high gear and the computer suddenly needs all that power, making the +12V rail collapse and the computers components experience kind of a "brown out" leading to undefined behavior, usually a hard crash. Modern power supplies are still to ATX spec though, and the +5V and +3.3V rails and all are still there, even if through the years manufacturers offer less and less amperes on them as the need just kind of vanishes. While old 200W AT- and early ATX-Power supplies often offer 21A on the +5V rail, you can find modern 6-700W power supplies that not rarely offer only 15A. It's just not needed. Usually, the power supplies regulates all of it's voltage around the +12V rail too, which means that the voltages on the +3.3V and +5V rail often fluctuate pretty wildly depending on what's happening on the 12V rail. Now, the ATX spec. says that under no circumstances in normal operation those voltages are allowed to leave the 10% tolerance range (no matter what happens on the +12V) but I have seen this happen quite often in many of the more cheap and also some of the more expensive supplies. Voltage spikes etc. on these rails are not uncommon when the load on the +12V shifts. Mainboard manufacturers are aware of all this and often don't really use anything besides the +12V rail, not even for the +5V USB supply of the internal USB ports, even *that* is often generated out of the +12V right on the mainboard. It's just more reliable that way. Often ripple etc. on these secondary rails is also pretty bad, even with expensive supplies. That's ok in how these voltages are used for new computers, but less so for the old hardware. So, when we connect a modern ATX power supply to an old computer (which mainly uses the +5V Volts, and maybe the 3.3V) we have created a very awkward operating environment for that power supply. First of all, the old computer only uses very little power compared to a modern computer, which makes the power supply run at a very bad efficiency factor (I can't cover all this in one post, if you are interested in what that means exactly, it's best to google it) in short making it waste energy and making the components of the power supply run hotter than they should and making the entire thing age prematurely. Then often an old computer barely uses the +12V for anything, which means the power supply has a hard time regulating the voltages it offers since it expects a certain minimum load on the +12V rail to do so. Some power supplies might even refuse to turn on under these circumstances and might require a dummy load (for example an old light bulb or power resistor, which again waste energy) on the +12V to even turn on that way. It's hard to say what the power supply will do in such a circumstance: Some might be able to regulate their voltages perfectly anyways, some might not turn on, some might generate voltages that are vastly out of spec. (5,9V on the +5V rail for example) I've seen all three happening. Modern power supplies also tend to bring up their voltages quite quickly at being turned on, which can absolutely murder the hell out of old MACH chips (send them into latch up) you find in old hardware quite often, when the hardware was poorly designed. (happens sadly more often than one should think, even if the MACH datasheets warn specifically about this and offer a way to design around that particular issue) Lastly, we usually get a very terrible step response (also called transient response) on a modern power supply on such low loads of 100W and less, meaning even small changes in load can cause voltage spikes on the rails which can damage hardware. +5V logic is less susceptible to that (although it certainly isn't great) but early +3.3V stuff is very easily wrecked by that as the tolerances are already tighter. An 68000 will survive an +7V spike no problem, an 68060 (a 3.3V, +5V I/O compatible device) interfacing with +5V logic which suddenly has it's Input Pins at +5,5V HIGHs might not survive. Terrible all around. As you can see, even if most of the retro community uses them, modern ATX power supplies are not good for old computers, even not old PCs. But what is? Difficult question, as power supplies that are designed around +5V and deliver enough might be hard to find. The easiest thing is just to use a period-appropriate power supply with your retro computer. I do this with my old PCs, I just bought old ATX power supplies (designed around their +5V and low-powered at ~200W) for my old PCs. You can even get (for that time good) power supplies often for only one buck and less, people throw these away and are happy to get rid of them. The retro community doesn't drive the prices as they usually only buy modern ATX supplies. (even if they are bad) The problem is that these power supplies often need maintenance and repairs and are rarely ready-to-use. Not everyone is up to that. Also many of them are quite terrible, especially in the 90s there were many bad manufacturers around, and many manufacturers that are good or acceptable now were bad back then. Also good manufacturers back then sometimes made bad supplies because they got into price wars with the competition, so it's hard to give good general advice. Generally it's the best to go with OEM power supplies that went into complete PCs, they usually went through some quality assurance of whoever put the PC together so they are not all that bad. Some manufacturers sell new old AT-Power supplies for legacy industrial and medical device purposes now, these are often high quality but can be hard to find and be quite expensive. The energy efficiency of these old power supplies usually is pretty bad. But well, I guess an old timer is not exactly green regarding its fuel efficiency either. You don't plan to make that 50 Mhz 80486 a 24/7 Server either, do you? A more modern solution would be power supplies that work directly with DC-DC conversion for all their rails individually. These don't care about load and have very low ripple. Be Quiet! makes some of those now and advertises with that, as such power supplies are highly energy efficient. They are also quite expensive. Can't say anything about the quality, as I have never seen one from the inside. PicoPSUs work the same way, they are good too but are pretty low powered and might not be enough for the application at hand. As you can see it's not an easy to solve problem for the average user. I hope I still could discourage some of you to use modern ATX-Power supplies. My fingers now hurt from typing all this on an entirely too small mini-keyboard. Police Automaton fucked around with this message at 11:02 on Mar 18, 2015 |
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Mar 18, 2015 10:46
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Police Automaton posted:I heard about this, didn't think it was that straightforward, Interesting! http://minipro.txt.si/index.php?title=Main_Page There's a firmware flasher that can either dump your current firmware, or install a new one. You select whether you want to re-flash the new firmware as the -CS or -A version. So you can dump your current firmware and then write it back as -A firmware and it will enable the ICSP port. There's also an updated version of the chip programmer software which cleans up the layout a bit, and fixes all the typos and Engrish.
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Mar 18, 2015 13:48
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