Need help restoring and wiring a WECo 151-AL / 634A Subset

[unbeldi]

The various versions of the subsets used various types of cord hooks.   Yours has a lug sticking out on the side where the mounting cord to the desk set enters, others have a circular spiral screwed into the wooden block, and I think there were others later on.

Diagrams also changed over time.   Your subset may never even have had a 634A diagram, since it is a refurbished 534 set, and they may just have covered the old diagram with lacquer.

[cloyd]

I located the size of the baseplate screws.  They are 6-32 x 3/4" round head screws.
Tina

[cloyd]

I hope someone can help me trouble shoot the problems with my phone.

The stick's symptoms:
No dial tone.
When a single number is dialed, I get about 3 seconds of dial tone and then it quits.

Subset
Nice double ring with an incoming call.

Thank you,
Tina

[poplar1]

Do you have dial tone if another phone connected to the same ext. jack (on Panasonic) or same line (if connected directly to the outside line without the Panasonic system) goes off-hook?  If so, then I believe you have an open transmitter circuit.

[poplar1]

The hole in the subset cover is for the cord (from the phone to the subset).

The transmitter screws are #2-56. If there are slits rather than holes in the transmitter bell (cup), then WE would have used screws with shoulders on them near the screw head.

[NorthernElectric]

Well, I'm not an expert on dials, and I don't know the correct name for the part that I think might be causing your trouble, so I'll just throw this out there for the real experts to comment on.  Your picture is not very high-res Tina, but it looks like the cam or actuator or whatever you call it that operates the shunt contacts s incorrectly positioned with respect to the contacts.  I have marked with a poorly drawn arrow where I think it should be.  Seems to me to explain why you get dial tone when you shouldn't and don't get it when you should.

Experts, chime in with comments and correct terminology please.

Thinking this through a bit more, I realize this would jam the dial unless the nut was loose and the cam was not turning.  Maybe I'm seeing something in Tin'a photo that's not there?

[cloyd]

Cliff,
I had this dial repaired by Steve Hiltz so I am going to go out on a limb here and say that I don't think it is the dial.  I have included a higher resolution photo for you though.  When I asked about my dial in an earlier post, people said that it was weird where the W terminal was located.

Poplar1,
The jack works fine with a WE500, so I think that you are correct.  I improvised a jumper from YY on the rack to the transmitter and that is very likely the culprit.  This is good news for me because I bought an old harness that looked to be in very rough shape to me and I was worried that I broke it when installing.  I will replace the jumper and see what it does.

Thank you,
Tina

[poplar1]

What I was asking you to do was to connect this phone and a 500 to the same jack, using a splitter. That way, you could see if the dial tone was present on the 151 AL when going off-hook on the 500.

You could do the same thing by just listening in the receiver of the 151-AL, with the receiver off-hook. From another extension, call the extension that the 151-AL is connected to.  Is the extension you called busy? If not,  see whether you hear the ringing voltage in the receiver of the 151-AL with the receiver off-hook.  If you hear that, then the receiver circuit is good, and, again, it's probably an open in the transmitter circuit (L2-Y on induction coil > Y conductor of cord to> Y-B terminal in base > blue harness wire to B on hookswitch > through hookswitch contacts to Y terminal on rack > yellow harness wire > Y on dial > through the dial pulsing contact springs (normally closed)  > BK on dial > transmitter (black harness wire) > through transmitter >  YY transmitter wire >YY/R on switch (along with red harness wire on same terminal)> red harness wire > R terminal on R/GN block > red conductor to subset > R on induction coil).

[unbeldi]

Your dial looks good from my view.  The "actuator", which the catalogs designated as the "Roller Arm", should be on the line from the dial center (rotor axle) to the axle of the pulse pawl, which appears to be the case.  The spring positions also are appropriate.

The three seconds of dial tone seem strange, the first digit timeout is much longer, so it might be the telephone that is cutting off the audio to the receiver.
If the set is not off-hook during this time, you shouldn't get any dial tone, so the loop is not open.


Does your telephone have loop battery?  Do you hear sidetone; when you blow into the transmitter, do you hear it in the receiver?

[unbeldi]

Tina, I think you would help yourself quite a bit, if you posted everything about the restoration of this telephone in ONE topic, in one place, not scattered in so many places. Someone that hasn't followed your posts, will have to ask the same questions about the history of the set that were discussed before, but few will take the time to research your posting history to find out what has been done to this set.

[poplar1]

No dial tone.
When a single number is dialed, I get about 3 seconds of dial tone and then it quits.

The three seconds of dial tone seem strange, the first digit timeout is much longer, so it might be the telephone that is cutting off the audio to the receiver.
If the set is not off-hook during this time, you shouldn't get any dial tone, so the loop is not open.

If this is happening off-hook, then this typically happens with a 302 with open transmitter. In these sets, turning the dial momentarily shorts L1 (R on dial) and L2 (Y on dial). This short on the line draws dial tone from the CO or KSU, but the dial tone goes away when the dial returns because the primary circuit is open. The secondary circuit, with receiver in series with the capacitor, is still in the circuit, so you may hear momentary dial tone after the dial returns, and you can also hear dial tone if another phone on the same jack goes off-hook (like the Monitor circuit on a hand test set).

I have not been able to duplicate this condition (3 second dial tone caused by dial shorting contacts) on a 151AL connected to a 302 base. Disconnecting either the YY or the black transmitter wire does create the "monitor" condition with receiver off-hook.

[unbeldi]

If this is happening off-hook, then this typically happens with a 302 with open transmitter. In these sets, turning the dial momentarily shorts L1 (R on dial) and L2 (Y on dial). This short on the line draws dial tone from the CO or KSU, but the dial tone goes away when the dial returns because the primary circuit is open. The secondary circuit, with receiver in series with the capacitor, is still in the circuit, so you may hear momentary dial tone after the dial returns, and you can also hear dial tone if another phone on the same jack goes off-hook (like the Monitor circuit on a hand test set).

I have not been able to duplicate this condition (3 second dial tone caused by dial shorting contacts) on a 151AL connected to a 302 base. Disconnecting either the YY or the black transmitter wire does create the "monitor" condition with receiver off-hook.

Yes, it wouldn't be three seconds, only perhaps 1-2 seconds max.

I don't how long the Panasonic PBX takes to recognize that an off-hook event is only spurious, i.e. is not actually off-hook, and withdraws dial tone.

[poplar1]

Yes, it wouldn't be three seconds, only perhaps 1-2 seconds max.

I don't how long the Panasonic PBX takes to recognize that an off-hook event is only spurious, i.e. is not actually off-hook, and withdraws dial tone.

Using a station port of a Panasonic KX-T30810 KSU, I tried removing the transmitter from a 201C-3E/634A, and the delay is in fact about 3 seconds before the dial tone goes away. Also with this model, with the transmitter removed,  turning the dial off-normal and releasing it shorted the line (or almost, with just the primary of the induction coil between L1 and R), and after the finger wheel returned to rest, there was again a 3 second burst of dial tone.

I haven't yet compared the circuit of a 151-AL with that of a 302 or 201 in order to understand why this same short of L1 and L2 (302) or R (induction coil) and L2 (201/202) does not occur. I suppose it is because there is no connection from R on the dial to L1 or R in the subset. In any case, I don't get the same 3 seconds of dial tone with the transmitter disconnected on the 151-AL. Therefore, I'm not sure why this is happening on Tina's 151-AL, unless there is a problem with the wiring.

[cloyd]

The temporary dial tone lasts less than three seconds as you are saying (more like 1-2 seconds).  Sorry, I didn't realize how important the time was.

I have tested the 151 using the splitter and a 500.  I get dial tone on the 151 although it is very faint.

When I dial the 151 extension with the 151 off hook, I don't get a busy signal but the subset rings.

I am going to begin testing for continuity along the route that you indicated for an open transmitter circuit especially along the old wiring harness.  I have several irons in the fire today so don't hold your breath.  I'll get back to it asap.

Tina

[cloyd]

...it's probably an open in the transmitter circuit (L2-Y on induction coil > Y conductor of cord to> Y-B terminal in base > blue harness wire to B on hookswitch > through hookswitch contacts to Y terminal on rack > yellow harness wire > Y on dial > through the dial pulsing contact springs (normally closed)  > BK on dial > transmitter (black harness wire) > through transmitter >  YY transmitter wire >YY/R on switch (along with red harness wire on same terminal)> red harness wire > R terminal on R/GN block > red conductor to subset > R on induction coil).

I have tested each of these segments within the transmitter circuit and narrowed it down to no conductance in the black conductor in the wiring harness.  Would a broken black conductor have the characteristics that I described?

Tina