MagicianLord77
Enthusiast
Hi guys, I'm looking for some assistance on bringing this Konami TMNT board back from the dead. Got it from an arcade parts lot. It had different issues that I've been able to overcome, but got stuck on this one.
Previous issues were:
Issue is that whenever speech is triggered (at the demo when turtles are hitting stuff, or at the beginning when turtles say some dialog), it sounds wrong. But it's not only that, eventually I guess the uPD7759 gets confused and starts playing on loop other noises, even when game ends it continues to play when it shouldn't (stops after a while, I've seen when its RESET signal is at some point of the demo loop). I guess this is because of some wrongly interpreted commands as the ROM it reads does not only contain samples but commands?.
Made some measurements with a scope over the lower address lines and data lines of the ROM, they all look pretty weird like this, how would you interpret this? I can't get to see anything square, slopes only, this didn't happen to me when measuring other boards so I would say the scope is fine. Also I've recently calibrated its probes with its 1khz square wave signal.
Seems there is a bus between the ROM data lines (output), uPD7759 (input/output) and 74LS273 (input).
Some docs I've been using:
What do you think? thank you!
Previous issues were:
- G8 BAD error - fixed replacing 051960 custom
- Title music caught in a short loop - fixed replacing 74LS393 of its circuit (independent)
- Sound would go out after a while of being turned on - replaced the LM358 and LM324 op amps but seems really fixed after replacing some tantalum caps near the amp, like many forum posts recommend
Issue is that whenever speech is triggered (at the demo when turtles are hitting stuff, or at the beginning when turtles say some dialog), it sounds wrong. But it's not only that, eventually I guess the uPD7759 gets confused and starts playing on loop other noises, even when game ends it continues to play when it shouldn't (stops after a while, I've seen when its RESET signal is at some point of the demo loop). I guess this is because of some wrongly interpreted commands as the ROM it reads does not only contain samples but commands?.
Made some measurements with a scope over the lower address lines and data lines of the ROM, they all look pretty weird like this, how would you interpret this? I can't get to see anything square, slopes only, this didn't happen to me when measuring other boards so I would say the scope is fine. Also I've recently calibrated its probes with its 1khz square wave signal.
- A0 goes out of the uPD7759 into the ROM address lines.
- Q3 is the 3rd bit of the ROM that also is in between a bus, more info below.
Seems there is a bus between the ROM data lines (output), uPD7759 (input/output) and 74LS273 (input).
Some docs I've been using:
What do you think? thank you!
