TRS-80 Model 4 help requested

From: Al Hartman <>
Date: Wed Feb 26 21:13:01 2003

> From: (Tony Duell)
> Try re-seating the 'ribbon cable' between the CPU
> board and the disk controller PCB _at both ends_. I
> would estimate that over 50% or disk problems on
> M3s and M4s come from this cable!

You're right about this. It all starts to come back to
me... *Grin!*

This was one of the first things I'd do when a machine
came in with disk controller problems.

I'd also remove the cable totally and clean the
connections with a pencil eraser and possibly some

Mostly, I'd just use the eraser.

Tin to Tin connections would often get oxidation.

Jerry Pournelle used to talk about something called
Stabilant-21 that worked well to keep this from

This stuff worked great on Model I keyboard to E/I
cables (I soldered on the infamous Gold Plugs on mine.
and made a gold and shielded cable besides) and floppy

But since the behavior changes when he moves the
drives, it sounds like his "0:" drive is bad.

Al Hartman
Received on Wed Feb 26 2003 - 21:13:01 GMT

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