I was poking around on my gate array and noticed my clock signal looks more like a pure sine wave than a square, so that has me wondering about the other signals. Does anyone know if there are images of proper gate array signals that I can compare against? I checked the service manual here on cpcwiki but didn't see any sample scope traces.
What's the bandwidth of your 'scope?
If it's not sufficiently high, it will falsely show rounding of the waveform.
100Mhz 1GS/s Tektronix TDS2012.
Also, are the cycle rates supposed to be rock solid at 16Mhz, or is a little back and forth fluctuation normal?
In my experience the raw clock signal comping out of the GA is a little 'woolly' - probably because it seems to use an open collector output with pull-up rather than a push-pull output. I'd suggest probing it after the inverter (transistor on a 464, IC on a 6128) here it should be better formed.