My Smart-1 4 line looses programming

[dagskarlsen]

My Smart-1 4 line version looses programming on power-outs.

I am not able to locate any internal battery for the memory. Any body out there who has solved that?

https://www.britishtelephones.com/smart14line.htm

All hints are welcome.

dsk

[rambo1152]

I looked at mine and can't find a battery or a supercap. Perhaps it is corrupt NVM that causes the processor to do a hard reset?

The only other thing is a "long star @ power-up" reset being performed, however unlikely.

Even when these were new, it could be a challenge to find a phone that sent continuous DTMF.

[dagskarlsen]

Originally Posted by rambo1152

The only other thing is a "long star @ power-up" reset being performed, however unlikely.

Even when these were new, it could be a challenge to find a phone that sent continuous DTMF.

At least I have such phone

[Dr-of-style]

You could put a small ups on it.
It would hold quite a while in an outage.
If there are no jumpers for ext Batt, not much you can do.

[dagskarlsen]

I had an American version not working too, that one had a leaking battery I have replaced it with something I had, time will show how it turns out.

dsk

[dagskarlsen]

I have changed battery on 2 of the American versions, one works like it should, but the other does not.
The other got a battery across the 5V capacitor, in series with a diode, I used a Li-ion battery (18650) and a resistor shunting the diode so it will "charge" with 0.1 milliamp to keep it full. (Do not know how that will turn out, but at least with new battery it keeps the memory for at least 12 hours, and so long power-out does "never" happen.

dsk