Poring over a few schematics, I see them connected both ways.
One one hand, microwave technology guru J. Carlton Gallawa says that it matters to achieve proper phasing (http://www.microtechfactoryservice.com/Ch7Pg6.html), but he does not explain what the abbreviations mean or what the standard is for connecting them!
I'm an electronics engineering technician and microwave servicer with over 30 years of experience, and it seems pretty obvious to me that "F" would stand for "filament" and "FA" stands for "filament, anode."
So I would connect to the "F" terminal the transformer filament lead which has nothing else attached to it.
I would attach to the "FA" terminal the other filament lead, which is also attached to the downstream side of the high voltage capacitor and to the "anode" of the high voltage rectifier diode.
William E. Miller, AS-EET
http://www.microwavecontrol.com
Microwave Oven Control Panel Repair Nationwide
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Proper Phasing and Life Expectancy of Magnetrons Used...
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SOURCE: Fuse is always blown
Thank you very much for your hint. I changed the transformer and it works now. I feel happy when the problem solved by my hand with your great help. You are really very good expert in both theory and practice. Best regards, Cuoitoet
SOURCE: Microwave - no heat
The filament reading sounds fine.
Here are some links you or someone you know can use for test help, but read their safety warnings first:
http://www.gallawa.com/microtech/mag_test.html
http://www.gallawa.com/microtech/xformer.html
Many brands have a "mini-manual" hidden inside the unit behind the control panel or hidden on the left side behind the grille, which is very helpful when troubleshooting & testing.
Please reply back with your brand and model number if you need further help.
We're happy to help and we appreciate your thoughtful rating of our answer.
SOURCE: LG MS-2143RSL MICROWAVE OVENT NO HEAT
hi i am suggesting that it is probably the magy as the res to grndis a bit low and therefore loading the sec supply down , just a thought
cheers grant
SOURCE: New GE Magnetron. Where does this new HV diode go?
Fixed it. There was a back capacitor fuse (I believe that's what it's called) on the old magnetron. I removed it and put it on the new magnetron. The HV diode is on the big silver capacitor and very easy to replace. I just didn't see it. It was definitely the magnetron and I hope that this new one comes with a warranty for 5 more years.
SOURCE: Magnetron will not run. I
You have replaced all those and still no go, well, In that case the main controller board is most likely faulty too. This is common, for the controller board and or power supply has been spiked.
HV TRANSFORMER
Remove lead wire.
Measure the resistance of the winding using an ohm meter
Primary winding 3 ohm (approx.)
Secondary winding 100 ohm (approx.)
Filament winding 0 ohm (approx)
HV CAPACITOR
Remove lead wire
Measure the resistance using an ohm meter set to R*1000
Terminal to terminal should momentary indicates several ohms but gradually increases to infinite.
Terminal to case should show infinite.
MAGNETRON
Remove lead wire.
Install the magnetron gasket in the correct position. Check that the gasket is in good condition.
Measure the resistance of the filament terminals. Normal magnetron should be less than 1 ohm.
Measure the resistance between the filament terminal to chassis. Normal magnetron should be infinite.
HV CAPACITOR
Remove lead wire
Measure the resistance using an ohm meter set to R*1000
Terminal to terminal should momentary indicates several ohms but gradually increases to infinite.
Terminal to case should show infinite.
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