Noticed some problems on my #Tommy which I thought seemed timing related, so I hooked my logic analyzer up to the IRQ test point and pin 39 of the CPU (which looks like it goes to the oscillator).

I'm getting a 1ms square wave (high and low each 1ms) on pin 39, which seems weird, but I must be measuring something wrong as the cpu couldn't even be working at that speed.

On the IRQ though, I'm getting about 1.3KHz, which I assume is not right. I know older williams run this at about 1KHz? I can't seem to find any info on the right speed for a Data East anywhere though. Not sure what to do about it being off either, other than replacing the three chips involved. I don't see anything timing related in the circuit though, which I don't get. Usually there's a 555 or something with some RC circuit involved.