q-bert last problem, video noise with sounds?

djdaveofkc

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I've got my q-bert about ready to go into my arcade but i have 1 issue left. Their is noise in the picture when you have q-bert jump. It does not do it in the attract mode, only when playing and it is definately related to the jumping sound. Thoughts?
 
well, factory grounds look ok, i'm gonna get some wire tommorrow and ground the heck out of everything. if this doesn't work i'm calling on you q-bert experts to help me out. Any suggestions would be great.
 
If I recall, the solution is to remove one of the grounds. I think its the yellow strap that goes to the filter board.
 
I tried removing the yellow straps one at a time and i could get the line noise to go away but then the whole screen had a different kind of noise. Tried some on, some off but same results. It's definately related to the ground. I'm gonna get some wire tommorrow and try some new locations for grounds. I'll figure this out somehow dammitt!!!
 
Thinking about this, i took off the silver cover over the pcb's. Wonder if this is partly why? Didn't notice this at all before this. Hmmm. Still gonna play with some new grounds.
 
ok, i'm stumped. If i take the yellow ground straps off the noise related to the sound goes away but the whole picture has a noise to it. Tried running a new ground from the monitor and still same results. Tried putting the silver cover back on, same thing. I tried regrounding each yellow strap, tried on, tried off but same thing. I can have the picture perfectly clear with some sound related noise, or no sound related noise but a "fuzzy noise" to the whole picture. Thoughts. I"m stumped at this point.
 
Just a new Q*bert owner's opinion (take it with a grain of salt). Does your machine have that shiny cardboard shield in between the boards on the door and the rest of the machine? Mine came with it and I thought about ripping it out, but I also thought about it possibly being in there for a reason...maybe to stop some interference from happening? I mean, why would they put it in there in the first place if it wasn't meant to prevent something like that?

Just a thought. If you don't know what I'm talking about, I can take a pic of mine if you need a reference.
 
Hi, yes it did but i took it out because i'd read that it blocks in the heat which is hard on the power supply etc, but now that you mention it it was in there 30 years without issue also. Wish i'd paid more attention before i ripped it out if it was doing the noise thing. When i take the ground straps off by the filter board and by the power supply the lines go away but the whole picture becomes fuzzy( hard to describe). wasted another 45 minutes on it tonight.
 
Q*berts are tricky beasts. Mine likes to blow fuses frequently. Good luck w/ yours!
 
I know this is an old thread but I'm just posting in case somebody else finds it via search. I ended up correcting this issue by turning down the sound on the sound pcb and then compensating by turning the volume pot inside the coindoor up. I think this is basically a symptom of the source sound going into the line too 'hot', much like clipping you get if you turn an audio mixer's gain up too high.
 
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