m_thompson
Veteran Member
The PDP-12 at the RICM broke a few weeks ago, and I finally had a chance to look at it. When first powered up it will boot and run OS/8 from the RK05. It will not run SPACEWAR or TANK or any of the other demonstrations we normally use. It will run KALEIDESCOPE. That means that large parts of the machine are working OK including most of the CPU, Core, and even the EAE.
Sometimes OS/8 will hang in a loop where it is executing the IOT 6041 and a JMP -1. It is waiting for a character to be sent out the console serial port before it can send the next character. At this point I can toggle in a little program that sends the contents of the AC out the console serial port, waits for the character to be sent (IOT 6041), increments the AC, and loops. This works OK. If I now run OS/8 it hangs in the IOT 6041 and a JMP -1 loop again. We swapped the M707 Teletype Transmitter flipchip, but it didn't make any difference.
SPACEWAR loops in a JMP 0001 loop. This looks like it got an interrupt when it should not have.
It ran Instruction Test 2 successfully. We will run all of the processor diagnostics, and maybe one will find something misbehaving.
Ideas are welcome.
Sometimes OS/8 will hang in a loop where it is executing the IOT 6041 and a JMP -1. It is waiting for a character to be sent out the console serial port before it can send the next character. At this point I can toggle in a little program that sends the contents of the AC out the console serial port, waits for the character to be sent (IOT 6041), increments the AC, and loops. This works OK. If I now run OS/8 it hangs in the IOT 6041 and a JMP -1 loop again. We swapped the M707 Teletype Transmitter flipchip, but it didn't make any difference.
SPACEWAR loops in a JMP 0001 loop. This looks like it got an interrupt when it should not have.
It ran Instruction Test 2 successfully. We will run all of the processor diagnostics, and maybe one will find something misbehaving.
Ideas are welcome.