TMNT Audio Repair Help

dbstallman

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I'm working on a TMNT board and am having issues with the theme song playback (among other problems with the graphics, but those are later).

I've traced the problem down to a bad DAC, the YM 3014B, but I don't have one to harvest from any of my parts boards nor can I find one anywhere in the USA. Does anyone have a spare or one they can harvest for me?

Thanks,
Brian.
 
I wish mine did... I've got a copule of those for harvesting. Here's a picture of mine (I've already removed the YM-3014B) :

imag1089t.jpg



Although, you have me thinking..... I could try adding a socket and wiring up half of a YM-3012. That might work. I'll keep looking for the 3014, though.

Brian.
I have a TMNT parts board. This one uses a 3012 DAC.
 
Haha...oops missed that little guy. I have it. This game uses some funky stuff for sound.....I thought the007232 was the main custom DAC for the game.

It is for everything else, the theme song is fed directly to the 3014 from the D5 mask ROM on a completely seperate buss. That is why you can have a board (like mine is now) that plays all audio except the Ninja Turtles theme. It's also why D5 can be bad but pass the boot up tests, it's not on a buss that the main CPU can see... in fact, I don't even know why it's there in the boot test, the result is meaningless.

PM comming.
 
I've seen the D5 go bad more times than the 3014. Did you already verify D5 other than the on-board testing?

Yeah, I have already pulled the mask ROM and socketed it (you should be able to see the edge of the socket in the picture). It verified ok on my burner and when I put the 27C400 in that I had prepared, I got the same results.

I was pretty confident that it was the YM-3014B when I noticed there was a strong EM field around it. Anytime you got your finger within a half an inch of the chip you would hear a loud buzzing in the speakers.... That and the fact that I had pulled D5, replaced the ceramic resonator and compared the output of the LS393s to my working board with a logic probe (I picked some up as replacments anyway).... there really wasn't anything else left in the circuit that could be wrong.

bustedstr8 is taking care of me, though, so I'll know for sure in a few days.

Brian.
 
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