Microwave Front Panel Repair - MayTag MMV4203DW00

[caphair]

Yesterday the display started showing --SE--

Looked it up and from the MayTag site it says this means there's a short on the touch panel.

Opened it up and measured a short across diode D109. Removed it, diode tested fine out of circuit. Following its path there's a zener diode and a capacitor C110. Removed capacitor, tested fine out of circuit. Zener diode measures good in diode mode (not sure if this is an accurate test for zeners). With both C110 and D109 removed I can still measure a short across the empty holes.

Followed + side of the capacitor C110 and it goes to the top (in picture) of the display and there's a burnt mark. Would this be what's shorted? Don't have any experiences with how these displays work. Wasn't aware they themselves could go bad. Is it a vacuum fluorescent display (VFD)? It's a hassle to remove to confirm short is gone

[budm]

Re: Microwave Front Panel Repair - MayTag MMV4203DW00

When you said shorts, what is the exact resistance reading?
How about the straight pictures of the top and bottom of the board and the location of the so called shorts?

[caphair]

Re: Microwave Front Panel Repair - MayTag MMV4203DW00

When you said shorts, what is the exact resistance reading?
How about the straight pictures of the top and bottom of the board and the location of the so called shorts?

4.7ohms. Here are some more pics

[R_J]

Re: Microwave Front Panel Repair - MayTag MMV4203DW00

Check this site out and read post by Kean http://appliancejunk.com/forums/index.php?topic=12215.0
It seems to be a problem with the touch pad/ribbon cable not the control panel
I will take a guess at the 4.7 ohms resistance and bet its for the display heater. The display/micro etc. is working, if it was not you would not see the error on the vfd.

[caphair]

Re: Microwave Front Panel Repair - MayTag MMV4203DW00

Check this site out and read post by Kean http://appliancejunk.com/forums/index.php?topic=12215.0
It seems to be a problem with the touch pad/ribbon cable not the control panel
I will take a guess at the 4.7 ohms resistance and bet its for the display heater. The display/micro etc. is working, if it was not you would not see the error on the vfd.

Awesome thanks! That fixed it. Had to separate the ribbon cable where it folds onto itself with some electrical tape just as the post you linked to says.

Yeah I figured the 4.7ohms was for the heater. Wasn't sure how they worked but got a lesson out of it. Thanks again.

Do you know how this fix was discovered? I bet many people have ordered replacement boards only to encounter same issue again