TRS-80 (IV) help?

From: Dave Dunfield <>
Date: Tue Oct 12 13:33:58 2004

Hi Tony,

>My guess is that it's not talking properly to the 1793 disk controller
>chip. I have had this chip fail :-(. But you might start by checking the
>power supply (there's a second PSU board in disk units, mounted on the
>side of the drive tower, which supplies the disk controller board and
>drives). And then check and re-check that ribbon cable.

I have determined that it is indeed the 1793 disk controller chip ...
I borrowed one from another system, and as soon as I powered up, I heard
the floppy seek to track 0 - stuffed in a boot disk and it booted right

I agree :-( .. I don't have a spare 1793.

Does anyone have an extra Western Digital 1793 (or compatible) FDC
kicking around? Bare on on a board (I've got a good desoldering
station) ???

dave04a (at)    Dave Dunfield
dunfield (dot)  Firmware development services & tools:
com             Vintage computing equipment collector.
Received on Tue Oct 12 2004 - 13:33:58 BST

This archive was generated by hypermail 2.3.0 : Fri Oct 10 2014 - 23:37:22 BST