Microwave powers up but no function
Panasonic inverter nn sn966s displays 8888 and then nothing works with the keypad. What is this
crwdns2934109:0crwdne2934109:0
crwdns2889612:0crwdne2889612:0
1
848361
crwdns2934065:0crwdne2934065:0: 13
1
1
crwdns2933315:02crwdne2933315:0
crwdns2934051:0crwdne2934051:0
crwdns2934065:0crwdne2934065:0: 55
2
Have had the microwave for about 2 years when it just suddenly stopped working, which seems to be about the amount of time before it goes bad. There's clearly power but the 8888 code and the keyboard doesn't work when you try to push buttons. We tried turning it off and back on after 10 minutes like some of the recommendations but we figured it was either the control panel or membrane her other users. The control panel seemed more likely since we have had quite a few times over the past couple of years where we lost power and probably had a power surge. Between the cost of the microwave and the built-in frame it would have been over $500 to replace them. So we paid the $68 for the OEM control panel and replace that. It works fine now. We are also plugging it into a heavy duty surge protector so we can hopefully prevent this from happening in the future.
crwdns2934105:0crwdne2934105:0
crwdns2889612:0crwdne2889612:0
2
crwdns2934065:0crwdne2934065:0: 6crwdns2936485:0crwdne2936485:0
4
5
I can't find a service manual for a 996. The 8888 comes from a power on reset cycle that is driven from the main board. The kbd is input to the main board. Without a schematic, it is hard to say what on the main board is bad. If the common things, switches or HV diode were bad, you would still be able to use the kbd to set time, etc. Since nothing works, something on the main board is malfunctioning.
I would remove the main board and first do a careful visual for any overheated resistors or expanding capacitors. Then try to test first all the diodes then the transistors on the board with a DVM. I say "try" because sometimes it is not possible to test them in circuit. If you find a questionable one you can remove it and retest it. However, if they are SMD parts, it will be difficult to remove/replace.
Otherwise, it is something else on the main board and you need to replace the board. I have a 997 schematic and there are a couple of PCBs. One has a power supply. If yours has more than one, do the above on it also.
PLEASE BE AWARE, THAT YOU MUST INSURE THE HV CAPACITOR IS COMPLETELY DISCHARGED AFTER OPENING IT UP.
Otherwise, you may become the problem. Refer to vidios on Youtube, if you don't know how to do that.
crwdns2934105:0crwdne2934105:0
crwdns2889612:0crwdne2889612:0
0
crwdns2944067:02crwdne2944067:0
This question was migrated from https://meta.ifixit.com/Answers.
crwdns2934271:0crwdnd2934271:0 iRobot crwdne2934271:0
@ryanljohnso6423 this particular Panasonic model has issues with bad Keypads. Try this first. Unplug the unit for about 10 minutes. Then consider that the 88:88 is what shows when you need to set the time. See if you can do that. Also try this:Hit the start button three and see if you get a Key icon on the display. That is the Child lock which locks the keypad. To turn it off hit Stop/Reset three times. See if that frees up the keypad. If that does not work, I'd suggest to replace the keypad and re-evaluate.
crwdns2934271:0crwdnd2934271:0 oldturkey03 crwdne2934271:0