Have you verified 5v on the vidiot at TP2? Since you've already tested the socket and chips verify its getting the voltage it needs.
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Have you verified 5v on the vidiot at TP2? Since you've already tested the socket and chips verify its getting the voltage it needs.
Quoted from ForceFlow:The thought was that if the capacitors aren't in good shape, it make take them longer to charge up to the expected 5v, which might be causing a delay for the reset signal on boot.
If he tries a manual reset after powering up that would prove that issue if he gets an instant test sequence, correct?
Quoted from ForceFlow:Good idea.
I would assume should be able to force a reset on the vidiot board, but I'm not sure which pins on the 6809 CPU at U8 would need to be shorted to do a manual reset, like on the pinball MPU. Pin 37 is for the reset signal on the 6809. I'm guessing you would need to short that to ground momentarily to drop the reset signal to low momentarily, then after releasing, it would go high again and go through a reset.
If he hits TP4 that should reset U8, U7, U16, and U27 all at once.
Quoted from titus:I still had the delay. I should have the new chip tomorrow. I will see how that affects the operation.
Quoted from jj44114:If you have a three second pause before any flashes I’m pretty sure you are not getting the first and second flashes. Most likely a problem with U27 or U29, or their sockets.
Based on that and your audio issue I'd agree take a look at U27
Quoted from titus:I installed the new 6803 tonight. It had no affect. Still have the delay before the flash. And only getting the seven flashes. I tried the reset again (tp4 to ground ) with the same result . I double checked the sockets and the traces. All good. I'm curious about the EPROMs.how often they go bad and how to diagnose if that's the issue??
Check the condition of crystal Y3 above the sound MPU, its possible you're not getting a clock circuit. Do you have a logic probe?
Try following the path of pin 40 out of U27, test pin 5 of U31 (74LS10 chip, could be failed) and then test pin 6 of U31 and then pin 22 of U29
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