Alrighty, new update!
I managed to score myself another two of these units in parts-mule and semi-working condition.
I've installed the Option 001 transformer, and replaced the main transformer with an older style and added the missing bridge rectifier for the +170v nixie supply.
Also, I used various other bits to replace missing parts in my unit, including that small box I was missing for the Dir. Count Amp board.
The semi-working one was showing random numbers on the display, so I began swapping the logic cards from my existing unit and found that the first one I swapped (board A23, Count Register Assembly) which I suspected, is bad, but the unit sprang to life with the replacement board from my original unit.
So this 'new' unit looks like it works on the BNC input at least which is awesome as I can use it for testing boards from my non-working unit, and I might even end up with two units working at the end (Assuming the front ends in both units aren't blown out.....)
Next step is to fix this A23 board just because it's known faulty, but I'll swap parts in and out of my original unit to get the display working right and also do repairs there as needed.
Interestingly, this A23 board is 4 layer, and gold played. Not a cheap board to make I'm sure from the mid 80's, the date codes on the IC's are around 1986...
Photos as follows:
- 'New' unit
- Original unit with stuff added.
- Faulty A23 board.