One observation ... though this was a new payphone when I purchased it back in the
1990's, the handset is cracked and I have not been able to unscrew the
earpiece or mouthpiece. Also need to find a wiring diagram to check that the handset
is wired up correctly.
Also, when I call the line, when I remove the handset from the hook, it does not answer the
call. Taking the handset off the hook is supposed to do what electrically?
Try to kill two birds with one stone. No, this board was the last of the dumb boards - it is line powered, and unlike the newer COCOT boards (programmable), needs no external power.
For handset wiring, see the information in that link I gave you earlier to the Sundance site.
There is a hook-switch in these which provides the switching for the handset- in this one, it is likely a micro-switch - if it were bad, it could conceivably cause the problem.
Re: Handset - the crack shouldn't cause a problem, but bad elements or conductors in the cord could. The earpiece/mouthpiece covers on all later payphones including this one are either glued or ultrasonically welded to discourage theft and cheating. You might be able to break the weld with a strap wrench, but there is also a possibility the plastic will break rather than the weld. They are normally replaced as a unit. However, I have managed to break the weld in a few of them successfully using a removal tool I have here, and also using a strap wrench.
I am surprised actually we haven't figured out what its problem is - the last one we were asked about is now working, though with slightly low volume. I suspect now we should be looking into a phone fault, such as bad handset or bad hook switch, both in the front cover...
Just a thought - you are remembering to re-connect the front panel to the bottom section when you are testing it - I know, dumb question, but stranger things have happened in the past
I have put out a call for documentation for this board, and if I am able to locate one, I will certainly share it with you in a PDF file. The problem may be is these are very old technology - they last made them in the early 90s, and there doesn't seem to be a lot of information out there about them. In fact, it is easier to get information on the earlier style boards Western used on the 1D2 than it is for this one.