PDP-11/10 repair started

Henk Gooijen henk.gooijen at hotmail.com
Sun Oct 4 14:26:31 CDT 2015

-----Oorspronkelijk bericht----- 
From: tony duell
Sent: Sunday, October 04, 2015 9:09 PM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: RE: PDP-11/10 repair started

> Oops, I forgot to mention a few other checks that I did ...
> AC LO and DC LO are some 4.6V. Both have a 130 mV ripple, no spikes.
> That seems OK to me.

Sure, those sound OK to me too. But you would have felt a right idiot if you
had spent days working through the microcode and CPU logic only
to find the real cause was something like that. Yes, I've been there,
done that...


> Thanks for the tip checking the microcode program counter. I hope to
> get to that next weekend. Also, with the correct module on extenders
> I will check what toggling LOAD ADDRS does signal-wise. Looking at
> the console LEDs it does nothing :-/

[... snip good microcode stuff ...]

Incidentally, is this an 11/10 or an 11/10S (what are the M-numbers on the
CPU boards)?



the microcode is "on the menu" for next weekend ...
The system is a 11/10S, CPU is M7260 and M7261.

- Henk 

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