Help w/ MM display???

This is called a hum bar. Easy fix, replace the filter caps on the A/V board. They will be 220uf/160v at c28 and c42.

You might also replace c29-c31 while you are are at it. These are .01uf/200v ceramics.

Edit: On *SOME* occasions, I've seen a broken solder connection cause this. Examine the solder on the bigger filter caps at c28 and c42.
 
So I finally got around to pulling that AV board but a few things don't match. C28 and C42 call for a 150uf @ 160v. Should I replace them with the same or increase them to what you suggested?
As for c29 - c31 .01uf @ 200v, I can find c29 and c30 but I cant seem to find c31? My schematics isn't the best so I may just not be able to see it, Any suggestions? Thanks for the help,

-Dave
 
So I finally got around to pulling that AV board but a few things don't match. C28 and C42 call for a 150uf @ 160v. Should I replace them with the same or increase them to what you suggested?
As for c29 - c31 .01uf @ 200v, I can find c29 and c30 but I cant seem to find c31? My schematics isn't the best so I may just not be able to see it, Any suggestions? Thanks for the help,

-Dave

Increase them. Sorry, forgot to mention the recommendation for change to higher value components. The 150uf/160v is a bizarre size that is a bit more difficult to find. The 220uf/160v is a much more common size, and in this circuit the increase doesn't hurt anything.

For the others, I'm looking at the manual and only seeing c29 and c30 as well. c31 does show up on the schematic though. :confused:

At closer glance, in the schematic it's connected with r33, looking at the parts diagram again it shows c3 in that position. Yet there's no c3 in the detailed parts list. I'm going out on a limb and saying that's a typo in the manual's diagram. It should be the capacitor right next to r33 (between r33 and r34). Unfortunately, I don't have a game in front of me to verify.

Also, I've verified this potential typo on the parts layout is the same in every WPC95 game manual. Hmm.

That said, I'm also going to go out on a limb and say the electrolytics at c28 and c42 are your "most likely" culprit here. The ceramics seem to have a much lower failure rate on the WPC95 stuff.
 
OK, Cool, thanks for clearing that up for me. I just got back from my local electronics store and they said the same about the 150uf's, not a common part. Unfortunately they didn't have any of the 220uf's ether... I'll get some ordered and replace them as soon as they get in. Thanks for the help, I appreciate it...

-Dave
 
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