13 May
2020
13 May
'20
6:27 a.m.
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