Re: black widow pcb problem no play no picture clock working

  I have a few boards laying around with 6502a cpu's in them. I have a
couple Space Duels I was going take the cpu's from.
Ok I will check the POR and Watchdog circuits again.
Thanks,
Dan

peter jones wrote:

>stop doing things till i check the schematics ;-)
>
>here is how it works (any game).
>
>the clock allways runs - so does yours, so that's a good start.
>
>the reset signal should start high and then pulse low for a second,
>or simply start low and then go high.
>
>if the cpu cant or wont run the reset should then start to pulse because of the watchdog.
>
>so the place to be looking is at the reset circuit and the asociated watchdog circuit.
>
>once the reset is acting right, then you can look at the address and data buffers or the cpu.
>
>have you got a spare 6502a for test?
>
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Received on Sat Aug 6 22:41:46 2005