PiDP-1 built test question

[Mike Katz]

I am testing my PiDP-1 with the I/O panel attached on a PI5 with 8GB of RAM with the stock PiDP-1 software.

When I toggle the second address switch from the right (A14 if the counting is left to right like it is on my PDP-8), with all of the other switches turned off I get see a flickering between the following

000002 000000 000000 000000
000002 000000 000002 000000

I disabled the LED test in pidp1_test to ensure there wasn't a short between one of the LED outputs and the switch input and the results are the same, it flickers between the two values.

Note:   The joysticks and bottom buttons are not attached for this test.

Does anyone have any ideas?  Could this be an unterminated input that will go away when the bottom switches and joy sticks are attached?

Thanks in advance,

             Mike

[Mike Katz]

Additional information added:

I am testing my PiDP-1 with the I/O panel attached on a PI5 with 8GB of RAM with the stock PiDP-1 software.

When I toggle the second address switch from the right (A14 if the counting is left to right like it is on my PDP-8), with all of the other switches turned off I get see a flickering between the following

000002 000000 000000 000000
000002 000000 000002 000000

Turning the Power or any other address switch on makes the phantom digit stay at zero.
Turning either the single step or single inst switch makes the phantom digit stay at two.
The Test Word switched have no effect.

[Oscar Vermeulen]

Mike,

Whoops - I just replied to your same question in the PiDP-10 google group, see the reply there.

In addition, my first guess is that you miswired the rainbow wires from top front panel to the bottom 8-switch panel.

But let me know by email to oscar.v...@hotmail.com! I will check for your message.

Kind regards,

Oscar.