PDP-11 with ATX power supply

Earl Evans earl at retrobits.com
Sat Mar 7 21:38:58 CST 2015

Hello fellow DEC enthusiasts,

I have a BA11-N mounting box with Q18 9-slot quad-height backplane. The
power supply is toast. My goal is to hack it into something useful.

I'd like to replace the power supply with a sufficiently-powered ATX PSU.
I've read the instructions at:


However, unlike the DEC PSU, the ATX power supply won't supply a 60 Hz line
time clock (LTC) signal to the backplane via BEVENT. So, my question - has
anyone used a standard ATX PSU for a PDP-11 QBUS system, and if so, how'd
you work around the LTC issue?

Once I solve the power issue, I have 11/23 CPU cards, RAM, and SLUs galore.
I'm not planning to make this very power hungry though.


- Earl

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