Resurrecting a PDP-12 in Duluth

I replaced the last two output flip flops (e5 and e10) and put the Flip Chip back in the computer. I ran the send/receive program to test things out. No errors in the received characters were seen. To test things a little further I loaded the BIN loader and started loading some diagnostics, and finally, the "Acid Test" as Warren used to call it, I loaded Focal (which is a large enough program it is broken into two parts.) All of these ran perfectly. Interestingly, when I clipped out one of the 7474s, a small piece of the plastic case fell off, so it would appear that this one was most certainly a problem. Soon a friend of mine, and myself, and I will be working on getting the ASR33 Teletype up and running.  Stay tuned!

It's been quite a while since the last post, and now that my final exams are done I have time to get back to work on the PDP-12. Recently, one problem that we have been experiencing is with the communication between our terminal computer and the PDP-12. When running OS/8 we noticed that sometimes when we press a key, the character that is printed on the screen is not the one that was pressed. The problem was sporadic at first, but quickly became more frequent, until it became frustrating to type anything because it would never send correctly. Another problem was/is with sending BIN programs. We have never had problems with sending RIM programs, bit BIN programs always seemed to fail half of the time they were sent. Sometimes the BIN loader doesn't send correctly, sometimes the program being sent using the BIN loader stops sending half way through, or it will send completely, but it won't run. Both of these problems seemed to be linked to the Teletype Receiver Flip Chi...