Ericsson 51 not transmitting

[Volvoguy]

I'm trying to fix up a wall mount type 1951 for someone, and it all seems to be working except the transmitter. I found the wiring diagram inside it, and it all seems to be wired right. Just not sure if there is something different from Europe to north America that I have to change around? The line cord is currently on 5 and 9,and the handset cord is on 5,6,7 (red, blue, yellow). Not sure where to start, so any help is appreciated.

Also it has a white button on the front, I think I have seen this refered to as an "earth" button? Is it fine to leave it as is? Or do I need to take it out of the circuit?

[unbeldi]

I am not sure whether the wall phone terminal numbers are exactly the same as the desk set, but I suspect so.  I have the line connected to 9 and 10, I believe. 5,6, and 7 seems correct for the handset cord. So, it seems that your line cord should not be on 5 (behind the transmitter) but before, such as terminal 3 or 10.

Can you post your diagram? Would be nice to have a record of it.

The earthing button shunts the line (a) to ground, so if you don't have the ground line connected to anything, it has no effect.

[Matilo Telephones]

The ericsson 51 (both wall and desk) has 2 different versions regarding the line cord.

The "normal" way would be

9 yellow EW (extra bell)
10 blue B
11 red A

With 9 and 10 bridged

This is the normal way, because its cousins the Heemaf 1955 and Standard 1954 use the same connections.

The other version is

9 Red A
10 Blue B
11 Yellow EW

Again B and EW should be bridged if you want the bells to ring.

Which version you have can be determined by the diagram. But if it is missing (for the benefit of other 51 owners reading this), you can look at the back of the connectors. The wires leading to them are the same colors as the wires for the dial, handset and line cord.

[Volvoguy]

Thanks! Going out to enjoy the sunshine, but will post the diagram and my findings in a few hours.

[Volvoguy]

Here's the wiring diagram. Didn't get a chance to play with it again today, but will tomorrow. There's a tiny bit of the diagram missing, seems like just the picture of the capacitor though. Let me know if i should scan it in better resolution.

[Matilo Telephones]

That would make it version no 2:

9 Red A
10 Blue B
11 Yellow EW

Again B and EW should be bridged if you want the bells to ring.

The rest would be

1 red (dial)
2 yellow
3 blue and if available green
4 blank
5 red (handset transmitter)
6 blue (transmitter and receiver)
7 yellow (receiver)
8 blank

13 is earth and does not need to be connected.

[Volvoguy]

Success!!! Switching line over to 9 and 10 worked perfectly. Now I just noticed the ringer isn't ringing so great. It rings, but very weak. Did they run off a different frequency over there? Is there a spring I can adjust on this one?

[Volvoguy]

I took the ringer apart a bit, and found the screw that holds the striker assembly to the frame. I slid it back a bit so the striker has more room to swing back and forth. That seemed to help.

[Matilo Telephones]

Very good!

Putting a tiny drop of oil on the pivots of the hammer (striker?) may help and adjusting the distance between the bells and the hammer too.

[Volvoguy]

How do you adjust the distance between the hammer and bells? I'm used to AE phones that have an offset hole in the bell.

[Matilo Telephones]

It is the same with the Ericsson 51. The holes are offset.

[Volvoguy]

You are correct! I didn't notice it at first, but after looking, i realized they are. Are the dials usually as loud when winding up as when you let go? This one is nice and smooth and works great, but is kind of noisy.

[Matilo Telephones]

These tend to go a bit noisy when they run a bit dry. I´d put a tiny drop of oil on the pivot points if I were you.

If it is dirty, you may want to brush the teeth clean, with an old toothbrush or something similar.

Here is something I wrote about restoring a type 51 wall phone. There is some info there on the dial and some tips on dial maintainance.

http://www.classicrotaryphones.com/forum/index.php?topic=10641.0