Terak 8510 system on eBay (# 300248208909)

Ethan Dicks ethan.dicks at usap.gov
Mon Aug 11 15:29:49 CDT 2008


On Mon, Aug 11, 2008 at 09:13:08PM +0100, Tony Duell wrote:
> > Of the half-dozen I have in the office basement - erhmmm - computer museum,
> > none power-up any longer.  I've resisted the urge to board-swap, waiting
> 
> I assume you have at least tried re-seating the boards (a suprisingly 
> common cause of problems in my experiece) and checked all the PSU rails.

Agreed - when we used to get calls from customers about COMBOARDs, one
of the first things we told them to do was to reset the board (most
commonly in a BA-11 or BA-23, depending on the model).

It fixed a large number of problems (well over 25%) and the customers were
very happy to be running again without having to wait for a replacement
board to be shipped.

Given that in our case it was rarely bad hardware, I have to suspect
something to do with tin-plated DEC backplane fingers and gold-plated
peripheral card fingers.

I've also had good results with pre-OMNIBUS PDP-8 gear by removing all
the cards, then cleaning the backplane with a chunk of manila folder,
cut to one 36-pin slot width, then dipped in >70% isopropyl alcohol
and run up and down each slot (switch to a new section when you start
to see grey streaks on the paper).  That one trick has taken machines
that wouldn't pass the simplest of toggle-in tests to passing most if
not all paper-tape tests - no actual bad chips, just dirty backplane
connections.

Since the Terak in question uses LSI-11 boards, I'm guessing it uses
a DEC-compatible QBus backplane.  If not, then this technique may or
may not be particularly useful.  The H-11, in particular, does _not_
use DEC backplane modules, so I wouldn't expect it to have as much of
an effect there, for example.

-ethan

-- 
Ethan Dicks, A-333-S     Current South Pole Weather at 11-Aug-2008 at 20:20 Z
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Ethan.Dicks at usap.gov            http://penguincentral.com/penguincentral.html



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