Trimphone does not ring

[skrammd]

I have two Trimphones.

I bought the first as a converted telephone, but the ringer did not work. I checked the conversion, but that did not help, as the ringer still did not work (did not have resistor fitted)

I bought the second phone as it required conversion and still had the original line in cord, with terminals at both ends. I have carried out the conversion including fitting the resistor, and used the line in cord from phone number one, but this one does not ring.

I have searched on here and seen others have had the same problem, and I have released the screw so both phones can have their ringer turned off, but I have moved the dial to all positions to no avail.

Please advise.

Many thanks.

[AndiiT]

Hi,
Trimphones have a notoriously high REN, the first thing to check though is to make sure that your phone has been converted correctly, if you remover the cover by undoing the plastic screw underneath the handset rest (it's very long don't be alarmed if it doesn't seem to be releasing) check that the phone is wired and strapped as follows -

Handset -

White - T10
Red - T1
Green - T2
Blue - T3

Line cord and straps, this is what you really need to check -

Strap T16 - T17 - T18 - T19

Strap T5 - T6

Resistor between T4 - T5 (see further down re value)

Line cord

Red - T8
White - T18
Blue - T5
Green - T15 (spare)

Although the recommendation is to fit a 3K3 resistor I have sometimes have to fit resistors of up to 10K for reliable ringing.

Good luck

Andrew

[Dave Moll]

Also, stating the obvious, but ensure that the ringer volume control isn't set to off - only selectable (and deselectable?) with the cover removed.

[OscarFoxtrot]

Also stating the slightly less obvious, but if you are converting to a 3rd wire ringing (pin 3 on the socket) you need to make sure that your phone socket is actually wired to pin 3 with a ringing capacitor.

try plugging into an ADSL filter as this usually has a capacitor and will recreate the ringing signal on pin 3.

[skrammd]

I have checked it's wired correctly.
I tested it with an ADSL filter.
Still not ringing.

Thanks for the advise.

[Nickthedentist]

Have you got any other, more modern phones on the line? Do they carry on ringing normally, or does plugging-in the Trimphone stop them from doing so?

N.

[ThePillenwerfer]

It's possible that the line cord with the plug on is faulty, for instance if the plug has been put on upside-down it'll be connecting the ringer to pin 4 in the socket instead of three.

Do you have an ohmmeter or continuity tester? If so check that the blue wire is going to the third gold contact in the plug, looking at it with the flex towards you.

- Joe

[skrammd]

I'm going to test the lead.
I have checked previously that there is no short circuit between the wires, but did not know which pin went to which wire.
I will now check the blue wire.
Actually I did think someone had used an original line in, and just put a plug on that, so that may be correct.
Thanks again.

[skrammd]

I checked and the blue wire is in the third pin from the right.

I can not load a picture, but looking at the plug, with the flex towards me, the first and last slot have no pin. The others do.

[Nickthedentist]

That seems correct, depending where "the right" is!

Working from the end without the latch, you should see:

Empty,
White,
Green,
Blue,
Red,
Empty.

https://www.vintage-radio.net/forum/...2&d=1206469276

[Dave Moll]

Originally Posted by skrammd

looking at the plug, with the flex towards me, the first and last slot have no pin.

That is normal. As Nick says, these two pins are not used in standard telephones, and are normally omitted from the plug.

[skrammd]

Originally Posted by Nickthedentist

That seems correct, depending where "the right" is!

Working from the end without the latch, you should see:

Empty,
White,
Green,
Blue,
Red,
Empty.

https://www.vintage-radio.net/forum/...2&d=1206469276

I have just tested mine.
I have
Empty,
Red,
Green,
Blue,
White,
Empty.
Obviously wired wrong.

Next challenge, to test can I remove the pins.
I am looking at changing the cable any how, so just bite the bullet and buy new cable?

[Station X]

You have a red/white reversal, which is not unusual. Just reverse these connections in the phone.

I wouldn't advise trying to rewire the plug.

[Nickthedentist]

Just use the colours as they are, i.e. connect the red wire to the terminal in the phone where you had the white wire, and so on.

Edit... crossed with Graham, sorry.

[skrammd]

Thanks for that.
Still no ringer.
I have checked and there is no resistance in the wires to the board with the ringer on that.
I know I have jumped a stage I am sure.
Thank you.

[Station X]

So you are saying the ringer is open circuit?

[skrammd]

Sorry I got that wrong.

The wires that connect the telephone terminals to the board that the bell is on, are not open circuit.

I did read once about testing the phone with a voltmeter whilst it is ringing, but not sure if that is correct way to do it.

[Station X]

You can check for ringing current by connecting a meter on AC Volts (100V range) across the ringer. When an incoming call arrives the meter should indicate about 80V mimicking the ringing cadence. It's better to use an analogue meter if you have one as the results are easier to see.

[mike_newcomb]

Hi Skrammd, have you 'proved' the phone socket being used, in that it definitely provides a ring signal on pin 3, as I think a Trimphone requires this.

Best to use a known old phone for this, not a modern one that just uses pins 2 and 5.

I once spent ages tracking a 'no ring on some phones' fault and eventually traced to the Broadband Filter actually missing pins 3 and 4.

Regards - Mike

[skrammd]

I have a converted Bakelite Phone that works on that same Broadband Filter.

I do not have any other old phones as all are modern in the house.