Z-100 system repairs

[Herbert Johnson]

http://www.retrotechnology.com/restore/z_repair.html

It's been too quiet here in Z-100 land! Here's some summer fun; I've
repaired a number of Z-100 low profile systems, and showed how-to on
my Web site at the link above. These are pretty reliable systems,
especially considering they are over a quarter-century old! The
problems are mostly single-component failures and not hard to
diagnose.

I've not described floppy controller failures; the S-100 controller
cards do seem to fail beyond a fried tantalum capacitor! Of several
boards, *three* blew out the leading +12V tantalum cap (on the 18V
S-100 side of the regulator). Comments?

Herb Johnson
retrotechnology.com
(private replies please go to my Web site, not "gmail"

[Barry Watzman]

There is a schematic of the Z-100 power supply in the [RARE] Z-100
SERVICE manual (this manual was not available to the public at the time
that the Z-100 was in production). I scanned this manual (not sure if I
scanned it all or just parts .... it's in a HUGE binder, about 5" thick)
and my recollection is that I gave the PDF files to Howard Harte to put
on the web. However, since then, all Heath/Zenith copyrights were sold
and the new owners are "going after" web postings. The schematic is
early (pre-hard drive) and it's "typical" .... as the power supply was
revised a number of times and there were at least 4 externally different
versions (low profile floppy, low profile hard drive, All in one floppy,
AIW hard drive).

Barry Watzman
Wat...@neo.rr.com