Panasonic Inverter vs Panasonic Cyclonic Inverter Microwave Ovens

[oolloo]

I have a question for you guys , there are 3 types of inverters with Panasonic gen1 , gen2 and gen 3 aka cyclonic?

Do they all have matching magnetrons, or is the magnetron like a satellite dish in that it does only 1 job and what does the clever bit is the receiver and CA Card aka inverter board and logic board?

Also I'm seeing Panasonic cyclonic ovens are mostly on the larger size 1.6 cubic and higher , any ideas why?  Anyone have any teardown comparisons of the cyclonic inverter  vs inverter regular ?

I'm wondering what need to be changed to make a countertop mid size higher end Panasonic Inverter into a cyclonic.  As yet can't find my teardown or even repair of cyclonic anywhere

[xavier60]

The descriptions for the Panasonic cyclonic MW are too dumbed down to make much sense of.  I suspect that they have slipped in a stirrer fan.

[oolloo]

You mean in front if the magnetron?  Behind the formica?  So the magnetron and inverter board would be the same?

They're catering to the islaves re dumbed down

[xavier60]

I think the gen1 , gen2 and gen3 applies to the progression in inverter designs of which there are 3, the last one having only one IGBT.
I have not found any more detail about the Cyclone thing.

[xavier60]

A while back I fitted a gen2 inverter to a gen1 MW oven. It is now safe to say that it's a success.
I though I would be able to keep gen1 inverters working indefinitely.
They are developing a problem that I have not solved. The main IGBT goes short circuit and blows the fuse just as the timer hits zero.
Using the micro power settings quickly blows the IGBT also. Something goes wrong with the ZVS timing.

[amyk]

Other than the power ratings, magnetrons are basically identical from an electrical standpoint. They need a filament and a source of HV, that's about it.

[duak]

Xavier60, regarding the IGBT failures - I wonder if the magnetron is ageing and presenting a different load as it gets older.  ie., its equivalent resistance changes and alters the damping of the tank circuit perhaps increasing the peak voltage and current.  Also, when the inverter goes off at the end of a cycle, perhaps any stored energy has to be dumped as a safety feature to prevent emission with the door open and maybe the inverter can't handle the increased energy.

I have a couple of older microwave ovens.  One had a shorted triac that allowed the magnetron to continue to run after the time expired.  The door had to be opened to completely stop it.  If the normally closed door switch stuck closed at the at same time, it could have caused some excitement.

[xavier60]

I could see the IGBT turning on too early before the voltage rings to zero, getting worse at low power settings. The inverter is set to low power for a second or two just before the relay turns off. This is where it tends to fail.
I have 2 gen1 inverter boards with the same problem. I replaced some high value voltage sensing resistors that were drifting high with no good result.

[james_s]

Well if all else fails I suppose you could start replacing parts one at a time until you locate the fault. If you are seeing the same fault in multiple units it could be worthwhile. I would probably reverse engineer a schematic too, that might offer clues.

[xavier60]

Well if all else fails I suppose you could start replacing parts one at a time until you locate the fault. If you are seeing the same fault in multiple units it could be worthwhile. I would probably reverse engineer a schematic too, that might offer clues.

The last batch of IGBTs from eBay are low voltage fakes, so I won't be doing much for a while. The control IC is undocumented.
I patched up a broken gen3 inverter board(F66459X92AP) that I scored on eBay. It seems to run fine except that it rattles when supplied with over 220VAC.
Does anyone know if these gen3 boards are made for a specific mains voltage or universal? I have not been able to find this basic information.