Power On, or "First Light"

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After the power supply was running I had a friend help me put it back in the case (it's about as heavy as it looks). I left the CRT and the tape drives disconnected as I haven't gotten around to doing anything with them yet.

Fingers crossed, I flipped the switch. The fans came to life and the console lit up. No smoke!


Michael gave a good rundown of the switches and some basic tests we could run.

All of the switches should be forward, towards the computer. These are zeroes or off. The one that doesn't matter is the PDP-8/LINC switch. That just changes the processor it's running on. We left it running in PDP-8 mode.

To read from memory: Set the left switches to the memory address you want to read. The Least Significant Bit (LSB) is on the right. Hit the EXAM switch. The contents of that address are displayed in the Memory Buffer lights. Pressing STEP EXAM will step to the next address and display the contents of that address in the MB. This worked fine for as far as I tested it.

To write to memory: Set the address in the left switches and the data you want to write in the right switches, and then press FILL. Now the MA should have the address and the MB should show the data. Pressing EXAM to look at the contents of that address should show the same data that was put in earlier.

Switching between PDP-8/I and LINC mode can be done by changing that switch and then pressing I/O PRESET. The light should change. This works on ours.

The last test we ran was a simple Accumulator increment. Load 7001 on the left switches and then press DO a few times and watch the AC increase.

Below is a video demo of us running through some of these.

Edit: We were incorrect in the video. 12 bits is enough to address 4k. Math is hard sometimes. 


Next things to do: Run more diagnostics and simple toggle in programs to see what is and isn't working right now, and get the CRT capacitors reforming so we can power that up. 

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