TECH: Joust Sound Help

[CheffoJeffo]

Sound went out on Joust (again), so I decided to look at it tonight (flapping without sound is no good)

- Tested voltages at the sound board and was getting 9.8V at TP1 and -9.9 at TP2. TP4 was 4.97.
- Checked the 12V voltages coming off the power board and they were also low (10.3).
- Pulled out a switcher and handy-dandy ArcadeShop Williams power adapter and bypassed the linear PS.
- Voltages now OK at the sound board and I get sound ... for about a minute, then nothing. Power-cycle game and get sound again ... for about 1 minute.

I'll rerun the sound board troubleshooting list this weekend, but wondered if anybody had any quick thoughts before then (in case I need to run to the electronics store tommorrow ... I won't be able to go on Saturday).

Cheers & Thanks.

[CheffoJeffo]

Just so this thread doesnt dead-end like similar threads on RGVAC ....

Someone no CGCC suggested that it could be the PIA chip on the ROM board, so I swapped with a known good ROM board and still have the same problem.

I'm going to recap and reflow the sound board, as well as checking the chips. All I need is the time.

Cheers.

[grantspain]

its sounds like a chip or cap breaking down to me,really difficult to troubleshoot sound problems,could be sound amp ic,eprom,voltage reg-the fact it works for a minute or so may help you if you use a freeze spray on the components one by one,i think this is gonna be a pig of a job i'm afraid

[CheffoJeffo]

its sounds like a chip or cap breaking down to me,really difficult to troubleshoot sound problems,could be sound amp ic,eprom,voltage reg-the fact it works for a minute or so may help you if you use a freeze spray on the components one by one,i think this is gonna be a pig of a job i'm afraid

Thanks, GS.

I did check chip temps quickly today and thought I had it ... after I cooled the chip in question and powered back up, it worked great. Turns out that it was the power cycling.

The sad thing is that I recently traded away my only other complete Williams sound board (I thought I had a spare, but turns out it is not complete).

Ah well, I'm sure that it will be character-building.

Thanks!

Cheers.

[Kevin Mullins]

I had a similar sound issue on a totally different kind of board though.
Turned out to be one of the little tiny NON-electrolytic caps. (I forget now what kind it actually was) The little brownish orange disc looking ones. Apparently one legs had been broken off and it would cause it to do some pretty fluky stuff.
Pulled one off a dead sound board to replace it..... and it worked perfectly.
It's one of them things you hardly ever pay attention to ya know, until you've pulled most of your hair out.

Just thought I'd throw that out there.

[CheffoJeffo]

Resurrection time ...

I recently picked up another Williams sound board -- had some broken transistor legs, but otherwise looked good. Recapped the board and replaced the transistor.

Dropped it into my Joust and nothing ... no sound.

Damn. Again.

I was gently pulling the molex for the speakers (so I could test the pins direcly) and ... bam ... sounds ... Defender sounds, but sounds nonetheless.

Yay.

After some experimenting, I found that I had two problems.

1) Bad speaker connector
2) Bad Sound ROM

So, I guess I'll be making an order to hobbyroms today to get a couple of Joust Sound ROMs (since I now have two sets of working boards).

Took me bloody long enough to figure this out.

Thanks for your advice and help on this!

Cheers.