Wanting some help with a PDP-8/a

Michael Thompson michael.99.thompson at gmail.com
Wed May 13 05:27:30 CDT 2020

> From: Bryan Longram <Driverless at protonmail.com>
> Subject: Wanting some help with a PDP-8/a
> I acquired a non-functional PDP-8/A several months ago and in that time
> I've replaced all the outwardly damaged parts and have gotten the machine
> to power on with no issues. However the problem I've been having now that I
> can't quite seem to pin down is that every time I power the machine the
> address field is displayed as 07777 and the value field is displayed as
> 7777. Attempting to change addresses or the value of the address doesn't
> work as I can enter the value just fine but upon entering the Load Address
> button it defaults back to being all sevens.

I am in the process of repairing three 8/a Programmer's Panels. Two panels
had bad ribbon cables. A good panel exhibited the same behavior as yours
when used with the bad cables. I was able to cut the keying peg off two IDE
disk cables to try as replacement cables. They IDE cables don't fit well,
but do work. I will make new replacement cables for all three panels.

Michael Thompson

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