Hi Alan (and the rest of the list),
I have the technical manual for the Dick Smith System 80 Mk I and II. It
includes technical data, troubleshooting procedures and circuit diagrams.
I'm in Auckland, New Zealand. Think this might be of any help?
Interestingly enough, it mentions checking the temperatures of the RAM (ICs
Z27 through Z34) as part of the official RAM troubleshooting procedure - hot
RAM -> "REPLACE RAM", apparently. Replacements are to be "4116 type Dynamic
RAM of 250 nS or faster, Dick Smith part number Z9310". And no, that part
number no longer appears in their catalogue... surprise!
Other possible causes are listed as
- bad power supply, especially the +12V rail.
- bad 0.1 uF bypass capacitors
- connection between CPU board and interface board damaged or unplugged
- faulty ROM or CPU
To reset the machine, apparently it's necessary to hold down 'Break' and
'Reset' at the same time.
Good luck! If you can't resurrect it and/or get bored of it, let me know,
I'd be interested in this machine, it'd be an interesting challenge to
repair it.
Mike.
----- Original Message -----
From: "Alan Greenstreet" <aeg_at_paradise.net.nz>
To: <cctalk_at_classiccmp.org>
Sent: Saturday, May 03, 2003 10:52 PM
Subject: TRS-80 / System 80
> Hi All
>
> I have just acquired a System 80 MkII (distributed in Australasia by
> Dick Smith Electronics).
>
> On power up I get the LED power light ok but a screen full of random
> characters, the reset switch does nothing. I've had it apart and there
> are no loose connections or chips on the two main boards and no sign of
> any burnt or expired components.
>
> Has anyone had similar problems and / or knows what the problem is?
>
> Thanks
>
> Alan
Received on Mon May 05 2003 - 22:16:12 BST