Coin Telephone No. 24A (NZ)

[LoganEnglish]

Hi all,

A couple of us downunder are working on trying to get an old payphone going again, see photo attatched. Does anyone have any circuit diagrams/knoledge to share on these? There are several plugs down the bottom, the functions of which are very unclear indeed. From what I gather, Singapore and the UK had the same model.

Kind regards,
Logan

[tubaman]

I used to work in the BT Factory in Enfield, North London, in the mid '80s to late '90s where the circuit boards for these were repaired and I seem to remember they need to be programmed before they will work using a Tester 297A (CT24 info on Bob Freshwater's site - https://www.britishtelephones.com/ct24.htm).

[LoganEnglish]

where the circuit boards for these were repaired

As I understand it, the circuit boards didn't survive in New Zealands humidity.  The solution was to wrap the board in a chicken bag and seal it off untill a new board could he sourced. Kept the phone working, but most unusual for linesman opening phones for repair.

[tubaman]

The boards didn't like the UK environment much either so had to be conformally coated. I had quite an involvement in that process at the factory as we had to strip the boards before testing and then recoat them once repaired. Recoating involved 'booting' all of the connectors and IC sockets before they went through the coating machine and then hand touching around where the boots had been afterwards.
We also used to repair and calibrate the coin runways, which were very finicky things indeed.
Fun times!