PTT Sodeco Kimus 1 TE-400-1

[Tech&Music]

It's been quite a while since I last posted here, but I recently got this payphone and was hoping y'all might know how to help me get it going.



It's the Sodeco TE-400-1, here in the Netherlands issued by the PTT as the "Kimus 1". It was found in the PTT's phone booths, and later on repurposed in businesses as the PTT was decommissioning them from booths in favor of more modern touch tone payphones, allowing business owners to have rugged, wallmounted payphones to generate extra income.

Mine is in need of some help. Currently, it's not ringing when called from my PTT Homevox PBX, though it can establish the incoming call. The microphone works, but the speaker remains muted. This Kimus predates the Kimus 1a, which contains various ICs and operates fully from phone line power. This earlier Kimus 1 uses more basic transistors, and requires a 12V battery to be present to power some of the electronics. I figure these electronics currently not being powered is the main reason for the lack of full operation.

The locks were shoddily taken out, with completely non-fitting locks put in place without lock nuts, which do precisely nothing to lock the phone. There are gouges and scratches around the locks, which I'll have to see if I can at least fill up and paint to make them less noticeable, and I'll have to see if I can find suitable locks to replace these.

The battery installed appears to be original, though of a type I cannot find anything about. It appears to be a rechargeable 12V alkaline cell, in the (extinct?) 66210 screw-in formfactor. It's fully depleted and has leaked as you can see. I plan to replace it with 10x 1.2V NiCD penlite cells, in the hope that these will work in place of this dinosaur, including the charging circuitry.



The coin mechanism will need a clean and lube, Dutch guilder quarters sometimes get stuck or rejected, though it does still accept them most of the time, neatly placing them in the window. The coinbox is gone, for which I'll have to fabricate something, as the coinbox door has a pin to prevent it from being locked if the box is not present.

However, the main thing I want to achieve, is actual payphone operation. I would very much like for the phone to actually grab the quarters at certain intervals. From what I understand, "telefoontikken" (literally translated as "telephone ticks"), or the metering pulses, consisted of singular 50Hz pulses, somewhere between 45V and 60V RMS, superimposed on both phone lines, in common mode signaling in reference to the phone's ground (which would be required to be wired in). This would make the pulse inaudible in conversation, unless a ground wiring fault was present.

Here's a graph of this signaling that I translated:



AC electronics still kind of melt my brain, and trying to figure out how to replicate this has proven difficult for me. As this system was used in the Netherlands, and I believe a similar if not identical 50Hz metering pulse in the UK too, I was wondering if anyone else has tackled this before I potentially start reinventing the wheel, so to speak.

I would like for the pulses to start as soon as my Grandstream GXW-4008 has established a call, stopping once the connection has been dropped. I was thinking whether the RS232 port on the ATA could potentially output call states that a microprocessor driving the pulse generation circuitry could use to initiate and stop the pulsing, but I'm not sure as the RS232 port's not documented at all by Grandstream. Maybe that's grossly overthinking it, though.

If anyone has ideas on such a circuit, I'd love to know!

[countryman]

It seems rechargeable alkaline batteries are still in use, yet uncommon:
https://en.wikipedia.org/wiki/Rechargeable_alkaline_battery
Apparently they are not suitable for high current applications, where NiCd, NiMh or Li-Ion cells must be used.
It is known that also regular alkaline batteries may be "refreshed" at low current rates and that is what supposedly happens in the phone - the battery only has to give off a relatively low current for limited time, and then is recharged at low rate for long time. Maybe 8 normal 1.5 Volt alkaline cells will last long ways in the application?
Good luck with the restoration - metering pulses are a tough challenge, be it those 50 Hz pulses or 12 or 16 kHz like in other countries.

[Tech&Music]

It seems rechargeable alkaline batteries are still in use, yet uncommon:
https://en.wikipedia.org/wiki/Rechargeable_alkaline_battery
Apparently they are not suitable for high current applications, where NiCd, NiMh or Li-Ion cells must be used.
It is known that also regular alkaline batteries may be "refreshed" at low current rates and that is what supposedly happens in the phone - the battery only has to give off a relatively low current for limited time, and then is recharged at low rate for long time. Maybe 8 normal 1.5 Volt alkaline cells will last long ways in the application?
Good luck with the restoration - metering pulses are a tough challenge, be it those 50 Hz pulses or 12 or 16 kHz like in other countries.

Indeed, I had ordered a 10 AA holder, with the plan of testing it with 8 regular alkalines first. That does power the electronics, and I can hear the relays operate in the phone. Seems to stop the horn-tap trick to dial numbers when the rotary dial is disabled.

However, I have come to the conclusion that was a red herring to my speakers, bell and dial issues. It seems like moisture got to this phone at some point, and killed the bell coil, speaker module and dial. I found an external bell with the same coil, which made the bells in the payphone work again. The contacts in the rotary dial seem damaged, and seemingly won't close. I also used the horn of a T65 phone, which confirmed the phone is operational. So phone wise, looks like all will be fine once I swap some parts.

[TelePlay]

Can you post an image of the back side of the dial?