Albert Otten wrote:
Another possibility to have the instrument atleast doing something is to bypass the Self test and
Extended Diagnostic tests by setting jumpers J712 and J713 on the I/O board to the 0 position. These jumpers are difficult to reach with the board in situ, I found it easier to remove the board and then change the jumper settings.
The only jumper labeled was J710, so I assumed the number went up went up from there. J712 and J713 were set to the right, so I moved them to the left, replaced the board and powered it up.
There was no change in behavior.
In reading the service manual for the 11801 it seemed to indicate that a sampling head needed to be installed. I tried it with one of my SD-22s installed, but that had no discernible effect.