Help needed identifying this telephone.

[AE_Collector]

So in the end, what are we calling this Telephone? A Standard Electric Whatchmacallit from Belgium?

Terry

[dsk]

I cant see anything wrong at the pictures, but the 3 contact springs at the right should be separated at rest position, and in contact (all 3) when the dial is turned out of rest position.
The dial pulses are obviously right, since you made a call.

The idea of the 3 contacts are just to short the receiver when dialling, to prevent clicks, and to short the transmitter to reduce the total resistance of the circuit, as a bonus the transmitter are also protected against spikes from the pulsing.

dsk

[jonboysez]

I'll have a closer look at the contacts on the right to make sure they are touching when they should be touching. There is definitely a dial tone with the transmitter removed from the handset.

[jonboysez]

I have checked the connectivity of the wires in the handset using my multimeter - there are no breaks in the wires - is there anything else I can check for connectivity? (I'm no expert with multimeter, only recently acquired it and used only for checking breaks in wires so far). The dial contacts look to be operating correctly. Have I got the wires to the dial completely the wrong way round? As you look at the back of the dial with wires connected it looks like red/white to second tag from the left, and black to second tag from the right (how anyone can tell which is red/blue as opposed to red/slate god only knows! I'm not colour-blind but its not easy, and then theres red/green as well - they all look fairly similar!). I was wondering, could you substitute a handset from a different phone to test to see if its the transmitter thats dead, or do you already know that it would make no difference? I have a lot of other old GPO  phones and some old foreign phones.

[dsk]

  I don't want to give up this!

About conductivity testing. The wires at the dial should have near zero ohms between:
1: the right screw, and L2
2: The next, and T
The 2 next and RT and R, I'm not sure witch go to witch.

Between the 2 right contacts it should be almost 0 ohms. Between any other contacts it should be more than 20 ohms (my guess)  or: It shall not be nearly 0, and it shall not be more than 200 ohms.

Another easy test could be to remove the handset cord from terminal RT. isolate it. (tape, or wrap some paper around it.) And try the phone.
Whats happening now?

dsk

[jonboysez]

Do I check those with the phone attached to the line or not connected? I need to go somewhere right now but will give it a try later on tonight.

[dsk]

The readings is best to do without connection to the line. The test with removed handset wire from RT needs connection.  You don't have to call someone, just dial one digit and try if you can hear yourselves.

dsk

[jonboysez]

Did you mean the 4 dial wires should be unscrewed from the dial to do the test? If so, the readings are:- far right to L2 - 0.8 OHMS, 2ND FROM RIGHT TO T - 38.9 OHMS, 2ND FROM LEFT TO RT - 38.9 OHMS, FAR LEFT TO R - 0.9 OHMS

[jonboysez]

AHA - disconnected the handset wire to RT, and when I dialed a number then spoke into mouthpiece I could definitely hear myself in the earpiece - that definitely worked! are we getting closer?

[dsk]

Yes we are closer 

My intention was to measure with the dial connected, but now my conclusion is, somethings shortening the transmitter. That is probably related to the dial.
If you disconnect the phone, and clamp the meter between T and RT (without connecting the RT cord, or if you have connected it already, unscrew the transmitter) The reading (ohms) should be unlimited.
If you get a low ohm reading, somethings shortening this. My guess is contacts or connection to terminals on the dial.

dsk

[jonboysez]

Right - telephone not connected to line, the 4 dial wires connected to dial, RT wire from handset not connected to RT terminal, ohmeter on 2000 ohms setting, reading with one probe on RT and other on T is 730 ohms

[dsk]

Sounds OK.
If you put back the RT wire, and ensure its not shorting to any other wire, it should work. The meter readings should be a little lower than if you measure between RT wire (before putting it back) and T terminal. (again I have to guess. 300-400 ohms at the first measuring and  maybe 200 at the second measuring)

dsk

[jonboysez]

The latest - tried checking resistant again between RT and T with RT removed but tonight I got a much higher reading than last night (why???) - tonight it was measuring 1936 but last night I only got 730 I then tried it with RT connected and got 40 ohms. Anyway I tried to call my mum and she still couldn't hear me, so I decided to disconnect RT and try that and she could hear me loud and clear! YIPPEE, BUT..............when she tried to phone me back she got automated message telling her that the line was busy................. does that give any more information to help me? Don't think I'm ever going to sort this. Half the problem is you can't see how the wires connect to the terminals in the phone - the wires are all tied together and don't think it would be a good idea to mess with that, likewise it would be good if I could remove the plastic piece off the 4 dial wires but then I would have tto do some soldering I think and would want to avoid that!

[dsk]

It may be the capacitor, that may also been whats fooled us earlier too.  Removing the strap (metal plate) between L1 and E stops the ringer from working, but if you have another phone ringing, it will be able to determine if the capacitor fools us, or not.

If you are trying to measure the capacitor with your ohm meter, short the capacitor for a sec or so before measuring. You have to measure with the phone disconnected, and the hook switch in on hook position.
The only right reading will be unlimited resistance. (open circuit)

(The simplest way to measure will be to measure between L1 and L2 in on hook position)
This will only measure the ringer capacitor part of the double capacitor.

dsk

[jonboysez]

Mmmmm - put one probe on L1 terminal and other on L2 (with wires to plug still attached but not pluged into socket) - got 62 ohms without pressing down the metal strip that plunger pushes down on, and got ZERO when I then pressed it down