Epson HX-20 repair details - more info

From: M.Clemence <M.Clemence_at_exeter.ac.uk>
Date: Sat Oct 26 22:09:18 2002

Thanks to the couple of guys emailing me about this I have measured a
few more things
after Tony Duell's advice as follows.

The three test points on the board are as follows with the machine off
labelled Vp 4.8V
             +5 0V
             Vc 2.86V

The transisitor Q8 has 4.8 V on the emitter but 0.18 Von the collector
the +ve side of Capacitor C11 is 2.86 V

pin 15 on IC7 is high

None of these values change when the machine is switched on.

As an aside, for those who maybe wondering why I'm bothering - I work at
from Exeter university
medical physics department and I have been
asked by one of our research groups to help them with a problem
regarding a pair of Epson HX-20's
(from about 1983). This group still use this machine to control a piece
of equipment which is used as
part of a large clinical study in diabetes and there is currently no
available replacement.
We are in the process of replacing these computers with newer machines
(for which we need to
replicate and validate that the software performs identically as before
which will take some time)
 but we would like if possible to keep them running in the meantime.

If any one would be willing to supply photocopies of the relevant bits
of the manual (schematic in
particular) I would of course pay towards copying/postage/time.

Yours

Matthew Clemence
Received on Sat Oct 26 2002 - 22:09:18 BST

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