Z80 CPU Replacement

[midipuppies]

Does anyone know the specs for a replacement Z80 CPU chip?
I guess I need the MHZ that it clocks at.
Jay

[Dimensional Space]

Jay,

I sent you a PM.   

James

[ryansupak]

You may have gotten this info already, but my understanding is that there are 4 "breeds" of the Z80. The difference is that they have different *maximum* clockspeeds:
Z80 - 2.5 MHz
Z80A - 4 MHz
Z80B - 6 MHz
Z80H - 8 MHz

There is nothing to prevent a "higher" Z80 from running at a slower speed, but running a slower one at a higher speed likely would not work (or shorten the chip's lifespan).

I ended up replacing my entire Z80 stack (it only cost a few bucks to do so.) Mine originally had (2) Z80A-CPU's in it but the corresponding CTCs (clock chips) were "original" Z80s. To me, this suggested that the system is probably running at 2.5MHz or less. So, to play it safe, I was sure to replace the Z80-CTCs with "original" Z80s as opposed to the "higher" ones. But it was OK to use "higher" Z80-CPUs since they can run slower if they want.

Honestly it probably wasn't necessary to be so choosy about the CTCs I used since I suspect that the clockspeed is set by the EPROM instructions, it's not inherent in the CTC. (It's just that the original maxes out at 2.5 MHz, the "A" at 4MHz, and so on.) But if somebody knows about that, one way or the other for sure, I'd like to know.

rs

[Electro disco club]

  Maybe it can help you if you're a technician