- minivanmegafun
- Jul 27, 2004
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op read this and get back to us
http://www.repairfaq.org/sam/micfaq.htm
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Aug 3, 2014 16:31
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Apr 27, 2024 04:20
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- minivanmegafun
- Jul 27, 2004
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Cross section diagram of typical magnetron
The really extraordinary ASCII art below represents (or is supposed to represent) a cross section of the 2M214 type magnetron (not to scale) through the center as viewed from the side.
code: ________
| ____ |
|_| |_| Antenna cap
/ |____| \
| | || | | Antenna insulator
| | || | |
xxxxxxxx|__| || |__|xxxxxxxx RF sealing gasket
____________________| || |____________________
| | (5)|| || || (5)| |
| | Top || || || Top | |
| | Magnet || || || Magnet | | Outer case
| |__________|| || ||__________| |
| ______| \\ |______ |
| /____ (7) \\ ____\ |
|____________|| \__ ______ \\ / ||____________|
| ||_______ |__ __| _\\ ___|| |
|____________|| | o || o | ||(4)||____________|
| || | o || o | || (6) | Heat sink fins
|____________|| Vane | o || o | Vane ||____________|
| || (3) | o || o | (3) || |
|____________|| | o || o | ||____________| o: Filament
| ||_______|(1)|| o |_______|| | helix
|____________|| __ |_||||_| __ ||____________|
| ||____/ || || \____||<-- (2) |
| \______ \\ \\ ______/ |
| __________ | || || | __________ |
| | (5)|| || || || (5)| |
| | Bottom || || || || Bottom | |
| | Magnet || || || || Magnet | |
|________|__________|| || || ||__________|________|
| |__||__||__| |
| | || || | Filament |
| | || || | insulator |
| (RF chokes |_||__||_| |
| not shown) || || Filament/cathode |
| || || connections |
|____________________________________________|
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Aug 3, 2014 16:32
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- minivanmegafun
- Jul 27, 2004
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Microwave generator circuit diagram
Nearly all microwave ovens use basically the same design for the microwave generator. This has resulted in a relatively simple system manufactured at low cost.
The typical circuit is shown below. This is the sort of diagram you are likely to find pasted inside the metal cover. Only the power circuits are likely included (not the controller unless it is a simple motor driven timer) but since most problems will be in the microwave generator, this schematic may be all you need.
code: || +------------------------+
||( 3.3 VAC, 10 A, typical |
TP Relay or || +------------+------+FA F| Magnetron
_ I I __ Triac || | +-|----|-+
o--- _---/ --+---/ -- ----/ ----+ || +------||----+ | |_ _| |
| )||( HV Cap | | \/ |
AC I \ I=Interlock )||( __|__ | ___ |
Line | TP=Thermal Prot. )||( 2,000 VAC _\_/_ +----|:--+
o------------+-------------------+ ||( 0.5 A | HV |'--> Micro-
||( typical | Diode | waves
(Controller not shown) || +------------+---------+
_|_
- Chassis ground
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Aug 3, 2014 16:32
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- minivanmegafun
- Jul 27, 2004
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High frequency inverter type HV power supplies
While the vast majority of microwave ovens - perhaps every single one you will ever see - use minor variations on the tried and trusted half wave doubler circuit, a few models have been designed using solid state high frequency inverters - in many ways similar to the deflection/HV flyback power supply of a TV or monitor.
A typical circuit (from a Sharp microwave oven) uses full wave rectified but mostly unfiltered pulsating DC as the power to a large ferrite inverter transformer which sort of looks like a flyback on steroids. See High Voltage Inverter Power Supply from Sharp Microwave Oven. This means that the microwave output is pulsing at both 60 Hz and the frequency of the inverter!
code:
Bridge Rectifier Inverter Transformer Magnetron
o
H o----+---|>|------+--------+-------+ +--------------------------+
~| |+ _|_ Drive )::( Filament 1T #18 |
+---|<|---+ | --- 25T ):: +--------------+------+ |
115 VAC | | | #12 ):: HV Cap | +-|----|-+
+---|>|---|--+ +-------+ :: +-------||-----+ | |_ _| |
| | | ::( .018 uF | | \/ |
N o----+---|<|---+ Drive |/ C ::( 2,400 V __|__ | ___ |
~ |- o---| Chopper ::( HV _\_/_ +----|:--+
(Interlocks and | |\ E ::( 250T | HV |'-->
fuses/protectors | | ::( #26 Sense | diode | uWaves
not shown) +-----------+ +--+---/\/\----+---------+
o | 1.2 _|_
(Except for filament, # turns estimated) o H1 - Chassis Ground
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Aug 3, 2014 16:33
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Aug 3, 2014 16:31
