Path: utzoo!utgpu!water!watmath!clyde!cbosgd!ucbvax!RADC-TOPS20.ARPA!GUBBINS
From: GUBBINS@RADC-TOPS20.ARPA (Gern)
Newsgroups: comp.sys.zenith.z100
Subject: Re: Floppy Disk Controller Card Price.
Message-ID: <12369430662.9.GUBBINS@RADC-TOPS20.ARPA>
Date: 25 Jan 88 15:11:59 GMT
References: <[E.ISI.EDU]23-Jan-88.20:33:10.SAC.DYESGPF>
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 19

You can try the three ZDS parts 'junk' dealers in Benton Harbor
that were posted a few months back, but no garentees if it will 
function.   Heath Parts will carry the complete board for 6 more
years.   If the PC board itself is not physically damaged, the 
controller is not difficult to repair.  The 3 Western Digital ICs
are the ones that usually go.   Hopefully, nothing has upset the
pot settings at the top of the board.

If you can borrow a known good board and swap the ICs, five at a
time, testing the board as you go (praying that only 1 IC is BAD
95% chance) you should find the bad one.   Swap the 3 WD chips first.
If the board still doesn't function with all the ICs swapped (and
the board that you borrowed works with the ICs fromm the bad board,
then it is a problem with the 4 POTs OR the 3 Transistors.  Replace
the Transistors if the POTs have not been upset.

The POTs can be easily calibrated using the info in the Z-100
Tech Manual.
-------