MK 1 sound dead

WadeLanham

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Hey guys,

Looking for some possible things to try to fix this. Probably will just buy a replacement PCB but figure it's worth a try.

My MK 1 lost its sound. It's a rev 5.0 T-unit setup with the separate sound PCB (From memory, I'm thinking the earlier boards didn't use a separate sound PCB).

Game plays fine, and the sound test gives an Interrupt Test success message, but no sound is played. My assumption is something is wrong on the sound PCB, though I suppose it might be the main PCB. No other symptoms, just dead sound.

I tried reseating the chips, no change. That's about the limit of my troubleshooting ability, without more guidance.

Any tips? Or just buy a new boardset? (If you have a known good boardset or very nice original MK marquee, please let me know.)

Thanks!


Wade
wadelanham at hotmail.com
 

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Check your power supply, it's a very common issue with MK boards, I suffered it from it! Check your -5v

Theres a lot of good tutorials on youtube from a guy called MKEXPERIENCE, who happens to be a klover too. Your board is probably not dead, its just a power supply issue
 
If you don't get resolution, I may be able to help... I had 2 non working MK1 sound boards... Ended up ordering a 3rd (Haven't received it yet) While I am waiting, I started messing with my 2 non working sound boards and I was able to get one 100% working and the other 95% working!

So I will have an extra when I recieve the 3rd one.
 
do you have the proper wiring for the sound board?

ex. volume pot?

Check your power supply, it's a very common issue with MK boards, I suffered it from it! Check your -5v

Theres a lot of good tutorials on youtube from a guy called MKEXPERIENCE, who happens to be a klover too. Your board is probably not dead, its just a power supply issue

that guy has a lot of WWF video's there
 
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Yeah, it's wired correctly (it worked before, but just stopped one day out of the blue). But a bad ribbon or something could be possible.

Wade

try running the soundboard with no volume pot (run a wire from the 2 header pins that are normally used for the pot), do you get sound then (it will be loud if it does, do not run it this way for an extended period of time it's bad for the speakers and soundboard).

If you get full blast sound then there's an issue with your volume pot and wiring. if not then it's another issue. Doubt it's the ribbon cable but it's a possibility.
 
OK, I checked the voltages, they are all there at the power supply (including -5). I checked the power on the harness that goes to the sound board, and the 12V lines are around 13V, and the 5V line is around 5.1V.

I bypassed the pot, no change. I did find this though. If I turn the volume up, I get a brief glitch sound when I go into the sound board test in the menu. It's just a super short static sound. It goes up or down with the volume adjustment.

Does this help any?

I couldn't find much on youtube except for bent pins and checking the voltages.

Mschwartz01, I might take you up on that if I can't get this going.


Thanks,
Wade
 
I had 2 non working MK1 sound boards... Ended up ordering a 3rd (Haven't received it yet) While I am waiting, I started messing with my 2 non working sound boards and I was able to get one 100% working and the other 95% working!

oh cool, I didn't see you update the other thread, what turned out being the issues?
 
If you don't get resolution, I may be able to help... I had 2 non working MK1 sound boards... Ended up ordering a 3rd (Haven't received it yet) While I am waiting, I started messing with my 2 non working sound boards and I was able to get one 100% working and the other 95% working!

So I will have an extra when I recieve the 3rd one.

Yeah - what did you do to get yours working?

Thanks,
Wade
 
Yea, I haven't gotten around to updating the other thread...

The first sound board was just producing static. Pulled each rom, cleaned the legs and it was good to go. The second board that I say is 95% working is the one that is the one that is in the video. The voices are better but it still isn't working as it should. Didn't have to replace any crystals.

On a positive note, I found 2 local electronics supply stores that I have to scope out. A fellow customer at radio shack was telling me that their drawers full of parts make radio shack look like a garage sale...

I can't wait to go check them out!
 
I recently got one to work that was totally dead by replacing the tall capacitor by the heat sink. (C95)
 
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