Bad Audio on Turtles in Time

rikitheshadow

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Just posting this to see if I can gather some information on an issue like this. I've got a TMNT 2 : Turtles in Time board that works....technically. There is a slight audio issue with the board. I noticed when I first loaded this up in my 4p konami cabinet that the attract audio was off. I proceeded to the test menu, turned it on, and successfully exited the test menu. I really wanted to hear that goofy song made for the attract loop for some old time sakes, but it was like tearing horribly to the point that you could not make out anything. Like it was just ripping the speaker a new one (pluged in and set to mono). It was super loud and just sounded like some horrible beast was screaming in a microphone. Anyways the funny thing, that seems to be the only audio that screws up, everything else plays fine. So I checked in the test menu on the sound bits and junk. There may be a few more than just the attract loop that tears up, but mostly everything checks out alright. So I initiated a Mask Rom check and the results where reporting one bad Mask Rom, "1D." Now from what I can gather online that is a chip or processing function to the audio output.

Right now I do not have a Probe to run tests on chips. Though I really wouldn't know where to start. I do however have the manual along with its schematics for the board.

Would anybody know where to start or how to solve an issue like this?
 
The mask ROM 1D is where the audio PCM data for the theme tune lives, so the fact the board reports that as bad makes sense with the fault you see. However it is not necessarily the mask rom that is at fault, I have seen similar issues on a TMNT board where the mask rom was not being addressed correctly as 2 out of the 3 74ls393 counters nearby were missing their outputs. What I got was a long howling noise, depending on which counter I repaired I got the same slice of the theme played over and over again, until all the counters were fixed.

But then again Mask roms do seem to fail on Konami boards, especially ones by the edge of the board where they get handled.

So - three options really

1) Bad mask rom
2) Bad controlling logic
3) Physical damage in that area of the board, bent pins etc etc.

If you can get hold of a probe you should be able to see rule 2 and 3 out easily.
 
Is there anyway you could help me locate the appropriate Mask Rom and the possible Counters that correspond to it. Still very new at this, but I do plan on purchasing a probe soon to help me locate issues.
 

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The rom is marked with the red circle, not sure what support chippery this has, the schematic online is missing a few pages so its not covered. Can you take a good high res, non blurry photo of this area of the board?
 

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Was too large to attach, so here. Errrr, just gotta rotate it....lol

DSC00058.jpg
 
Hmm, cant really tell much from the photo, I was hoping to see where certain tracks went. It also seems like the relevant pages were missing from the official schematic pack released by Konami, I had hoped the Sunset Riders schematic would shed some light but it too is missing the same pages.

I have a SR PCB at home so will buzz through the control lines for that ROM tonight.
 
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Hmm, cant really tell much from the photo, I was hoping to see where certain tracks went. It also seems like the relevant pages were missing from the official schematic pack released by Konami, I had hoped the Sunset Riders schematic would shed some light but it too is missing the same pages.

I have a SR PCB at home so will buzz through the control lines for that ROM tonight.

Good luck... Both the boards I've worked for audio issues had dead or messed up 053260 chips.
 
Hmm, cant really tell much from the photo, I was hoping to see where certain tracks went. It also seems like the relevant pages were missing from the official schematic pack released by Konami, I had hoped the Sunset Riders schematic would shed some light but it too is missing the same pages.

I have a SR PCB at home so will buzz through the control lines for that ROM tonight.

I could work on getting some scans of the schematics, although I'd have to piece them together. Their 2 pages in length and my scanner isn't big enough for that. That and I don't know if there is anything missing from them, but only if I need to though. I think I've seen a few on the web.......trying to piece them together in photoshop might be a pain cause I haven't touched it in like a year or so.

I'm gonna look up and down and see if I can turn up any results.
 
Good luck... Both the boards I've worked for audio issues had dead or messed up 053260 chips.

I'd say it couldn't be dead or there would be a lot more corrupted audio bytes. Possibility of messed up though.....there where actually a few prongs bent to the side on the right side of the 053260, i bent them back with a needle and tried running the board again. The audio on most of the vocal bytes are still screwed up. Maybe a slight possibility that may have screwed up that audio processor.

I ran through my schematics I had available in the manual. I found 1D in the schematic but its leads didn't turn up anywhere else, so I suppose mine is missing sections too. I ran a continuity test to see most of where the leads went to and it was mostly feed into the top half of the 053260 and 3 leads in to the top right half of it.

LoL Need to rotate my photo to understand what I'm talking about.
 
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Update to this thread because I like to follow through with my logs.

I brought my TMNT 2 with me to Raymond's (Channelmanic) Repair party this weekend to have some professionals take a look at it lol. =P

Anyways, we checked the Mask Rom and it seemed to be ok. We compared it with Raymond's Chip Max EPROM programmer/reader and it check out.
Which leaves it to be the custom sound chip, not the cap kind like on the X-Men boards, but the surface mount cpu chip. Part of it must be dead because we re-did all the surface mount soldering and gave us nothing.

As far as I'm concerned the game is bunk, BUT so far the game plays perfectly...just audio tearing on dialogue.....sound FX and music still roll out nicely though. Lucky it's even running....
 
That's the 4th one of those boards to cross my bench for audio issues and the 4th one to have a bad custom.

The ROM is accessed through the custom chip which controls the D/A (speech and other sound effects) conversion for those sounds. When that chip dies those sounds get garbled or just stop working.
 
That's bad news then, yeah? It doesn't sound like there's any way to fix it then. Poop, I was hoping to get a TiT board and I love that song...
 
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