Fix for flaky MS-SoftCard Z80 clones

[Tarkin <Tarkin000@gmail.com>]

This is a followup to problems I had been having with
the clone MS-SoftCard Z80 from Atlaz (my problem is
not with the vendor). The idea was to swap out chips,
which is not original!

The CPU mine came with is:
Goldstar Z8400A PS

Which I replaced with:
Zilog Z84C0008PEC

The system is far, far, _far_ more stable now.
I don't know if it is the fact that it's a CMOS
part, or if that the chip is faster, or both.
In any event, it's a cheap fix with immediate,
practical results.

As I write this, I'm transferring a 16K hex
record of Brad Rodriguez's CamelForth,
for the second time. The first went of without
a hitch, which is a minor miracle, but the
file was corrupted (possibly as a side-effect
of MyZ80's 'export' function.

As an aside, the RAMDRIVE.COM from
the CP/AM 4 CP/M disk WORKS with
MS-CP/M 2.23. It gives a 64K ramdrive,
which greatly speeds up serial transfers
and program execution.

Hopefully, this helps someone else out.

HTH and TTFN,
  Tarkin