PDP11/34 Restoration

In January 2020 (pre-Covid!) I bought a PDP11/34 off eBay.

According to the previous owner, it was used in the Austrian Research Centre Seibersdorf.

Here is the machine:

It came filled with cards:

• CPU (M8265+M8266)
• 2 RAM Boards (M7891-BA 64kx18 MOS Memory)
• 3 Serial Cards (M7856 SLU+RTC)
• PDP11/34 Console Controller (M7859)
• RL11 Disk Controller (M7762)
• A "GPIO" card (M7860)
• A mysterious "Keyboard Controller" (RCS003)

Over the course of the first lockdown in Spring 2020, I replaced all electrolytic capacitors in the PSU and successfully started it.

I also had to replace a failed 7812 voltage regulator and the caps on one of the M7891 RAM boards.

It successfully boots RT-11 off of an emulated TU58 and even assembled some MACRO11 programs!

My ultimate plan is to boot UNIX or Mini-UNIX, but this requires some more work on the disk subsystem.

See some more information here