This system came nearly complete, but was missing the cable that connects the power console to the backplane. I got one from the parts bin. I also had to move one of the molex connectors from the main transformer to a different location on the power backplane. Some of the cards were in the wrong slots. I wonder if this is why whomever had the computer originally gave up on it.
Next - "Testing PDP-8/A Without Paper Tape Diagnostics" from the Operator's Handbook.
First, I moved the M8316 from slot 4 to slot 3 per the manual Table 3-2. The manual says that the serial/console board (M8316) and extended option board (M8317) can be in either slots 2 or 3 interchangably. The M8315 (CPU KK8-A) has to be in slot 1 .
CPU switch 7 of 8 is the only jumper in the ON position of the M8515 CPU card. Switches 1-6 in the OFF position = 0000. This will cause the system to jump to 0000 and wait for console input.
The MM8-AA 8K Core memory card that came with the system was installed in a 4-hole backplane slot (!) so I don't think it's the right place for it. The jumpers indicate Fields 0 and 1 (W1-3 and W1-2 jumpers are connected). For now I removed the DATARAM card until I can learn more about it.
Powered on the system and ran the AC counter program from the manual. Works fine. Ran a few other front panel diagnostics and they checked out.
So I guess this works. Next, either find a Teletype to attach to this or configure for a serial terminal.
I posted a 14 second video to my Twitter account of the AC counter program running, if you want to check it out. My Twitter handle is @billdeg