WE 302 receiver volume low

[fairmont7]

Hi guys,

New to the forum and hoping to get some help figuring out what's up with my phone. I've got a metal case 302 that's had a pretty weak receiver volume since I bought it. I've replaced the cords and entire receiver (including elements) from Oldphoneworks, but none of this had remedied it. It's hooked up to an xlink Bluetooth box and I've found that right when it's plugged in, the dial tone is at its loudest, but fades as it sits, to the point where it's almost inaudible when listening for it. Testing on a landline is a bit better, but it's still weak. I find that if I play with the plungers a bit, pushing it down a bit and even twisting it, will sometimes get a louder dial tone. This leads me to believe it's the hookswitch, though at the advice of customer service at OPW, I've cleaned the contacts and ensured they're all touching.

I've taken it apart to paint and put it back together, noting that everything's wired up the way it was.

I'll buy another hookswitch, but I'm wondering if there isn't something else I should include in my order with them.
Thanks for any suggestions!

[unbeldi]

Welcome online!

Hookswitches rarely go backbad, if ever. You already burnished the contacts.
Buying single parts is always expensive from commercial places, usually the best place to get parts is another phone from eBay. There are many parts phones available for less that $20, and often even very nice ones that just need a little cleaning.

When you have a problem with a fairly long time constant as you describe, meaning a defect that takes some time to develop to its full state, then it is usually not something that acts abruptly, such as a switch.   The most obvious part that has a time constant involved in its operation is the condenser, nowadays called a capacitor.  That is the gray metal canister (lead metal) that is clamped to the base plate in the rear of the set.
This can has actually two capacitors in it, one for the ringer, and one for audio receiver circuit.

The audio capacitor prevents direct current from flowing through the receiver.  It has a fairly large value of 2 µF, so that it does not impose too much of an impedance to the audio signal, which it must pass.  So, perhaps your capacitor has some defect.  A capacitor takes some time to charge up.
However, a shortage of this capacitor should hardly be noticeable by ear, but it could be some combination of effects that cause your problem.
Every capacitor as old these are now, has some leakage, typically this is less than 1 mA, even less than 0.5 mA in the few cases I have measured.  If the capacitor is shorted the current should jump much higher to ca. 15 to 20 mA, depending on the condition of your telephone line.

Have you checked the wiring of your set against a reference?

Looking at some pictures of the inside might help.

[fairmont7]

Welcome online!

Hookswitches rarely go back, if ever. You already burnished the contacts.
Buying single parts is always expensive from commercial places, usually the best place to get parts is another phone from eBay. There are many parts phones available for less that $20, and often even very nice ones that just need a little cleaning.

When you have a problem with a fairly long time constant as you describe, meaning a defect that takes some time to develop to its full state, then it is usually not something that acts abruptly, such as a switch.   The most obvious part that has a time constant involved in its operation is the condenser, nowadays called a capacitor.  That is the gray metal canister (lead metal) that is clamped to the base plate in the rear of the set.
This can has actually two capacitors in it, one for the ringer, and one for audio receiver circuit.

The audio capacitor prevents direct current from flowing through the receiver.  It has a fairly large value of 2 µF, so that it does not impose too much of an impedance to the audio signal, which it must pass.  So, perhaps your capacitor has some defect.  A capacitor takes some time to charge up.
However, a shortage of this capacitor should hardly be noticeable by ear, but it could be some combination of effects that cause your problem.
Every capacitor as old these are now, has some leakage, typically this is less than 1 mA, even less than 0.5 mA in the few cases I have measured.  If the capacitor is shorted the current should jump much higher to ca. 15 to 20 mA, depending on the condition of your telephone line.

Have you checked the wiring of your set against a reference?

Looking at some pictures of the inside might help.

Thanks for the explanation of what the condenser does! I wondered if that may have something to do with it.  As far as the wiring, I plan to open it up this weekend and compare it to the wiring diagram I found online, as well as photos. I did a little digging on this forum and read that this could be part of the issue..

[unbeldi]

What I was going to suggest as a simple test of the capacitor, but in the end forgot to say after my rambling about the capacitor, is to take a wire, best a test lead with banana clips and short from the C terminal on the induction coil to the BK terminal on the dial.  The BK terminal is the one with two wires connected, one of them black.   This shorts the capacitor completely.  Does it help the problem or make it worse?

[poplar1]

The receiver is in series with the green and brown-blue hookswitch springs, and also the BB and W dial springs.

However, before burnishing contacts or replacing either of these parts, it's useful, IMO, to bypass both of these by temporarily connecting the white handset cord conductor directly to GN on the 101A induction coil. If the low volume is still present, then the dial and hookswitch can be ruled out as the source of the problem.

Hi guys,

New to the forum and hoping to get some help figuring out what's up with my phone. I've got a metal case 302 that's had a pretty weak receiver volume since I bought it. I've replaced the cords and entire receiver (including elements) from Oldphoneworks, but none of this had remedied it.  This leads me to believe it's the hookswitch, though at the advice of customer service at OPW, I've cleaned the contacts and ensured they're all touching.



I'll buy another hookswitch, but I'm wondering if there isn't something else I should include in my order with them.
Thanks for any suggestions!

[fairmont7]

it's useful, IMO, to bypass both of these by temporarily connecting the white handset cord conductor directly to GN on the 101A induction coil. If the low volume is still present, then the dial and hookswitch can be ruled out as the source of the problem.

Doing this makes the dial tone considerably louder. If I put the white wire back and move the contacts on the hookswitch around a bit, it impacts the volume, but only to make it softer, not louder. Could it be both the condenser and hookswitch that need replacing?

Thanks all for your help on this. Only just had the time to do a little troubleshooting today

[poplar1]

If the dial tone stays loud (doesn't fade) while the white handset wire is on GN, then I would move the white handset wire to BB on the dial (with the brown-blue hookswitch wire).

If the dial tone is no longer loud (with white handset wire on BB), then it must be a problem with the hookswitch (green and brown-blue). 

You can bypass these hookswitch leads by running a piece of wire from GN on induction coil to BB on dial. At least you won't hear the dial pulses (with the white handset wire on W). However, you will hear a loud pop when hanging up the phone -- maybe not as problematic as having chronic low dial tone.

[unbeldi]

Fairmont:
If you look at this diagram, the suggestions by Poplar1 may become immediately plausible and easily remembered.

The receiver is shown as a symbol (loudspeaker) at the far right, from which the white conductor goes to terminal W on the dial.


Western Electric 302 and 5302 Telephone – Circuit and Dial Schematics

You can follow the signal path left across the dial switch DS2, which is normally closed, and the hook switch HS2 which is closed when going off-hook.  Moving the white wire spade past these to terminal GN on the induction coil, bypasses any potential switch troubles.
If you move your eye further left, you arrive at terminal C which connects the condenser (2 µF) to terminal BK. The transmitter (TX) also arrives there, both with black wires.  If you bridge the condenser with another wire or test clip from terminal C to BK on dial, and have the white wire connected to GN, you are eliminating both the condenser and the switches, and if your set still has problems, you have to start looking elsewhere for trouble.

While you're at tracing wires in your set, please compare all the other wires against this diagram as well.  All wire colors are noted in the diagram, but often the colors are hard to recognize after 60+ years.