My 10/50 500 Has Gone Silent -- Help!

[rp2813]

Without any warning signs, one day it was working, the next day, dead.  Not even faint humming or static.  Just as if the phone wasn't even wired up.  Connecting another phone to the same jack gave me dial tone.

I switched out the receiver element and there was no change.  I made sure to jiggle the handset cord connections behind the spades to see if they were the problem, but still nothing.

Any suggestions on what else to check?  If it's the equalizer, I think I'm SOL.  That would be a real shame.  I love this phone, and it's my daily driver at my desk.

I don't want to go poking around under the case just yet.  Can anyone advise on a troubleshooting sequence to eliminate potential sources of the problem?

[Southernphoneman]

Without any warning signs, one day it was working, the next day, dead.  Not even faint humming or static.  Just as if the phone wasn't even wired up.  Connecting another phone to the same jack gave me dial tone.

I switched out the receiver element and there was no change.  I made sure to jiggle the handset cord connections behind the spades to see if they were the problem, but still nothing.

Any suggestions on what else to check?  If it's the equalizer, I think I'm SOL.  That would be a real shame.  I love this phone, and it's my daily driver at my desk.

I don't want to go poking around under the case just yet.  Can anyone advise on a troubleshooting sequence to eliminate potential sources of the problem?

First check your check your mounting cord, troubleshoot the basics, not sure about the equalizer part,try another mounting cord, try taking the 500 and plug it into another jack, also post some photos of the inside, a trained eye might see something.

[rdelius]

Part of the equalizer is a resistance lamp.if it is open, try shorting it to see if things work (but not perfectly)

[unbeldi]

The resistance lamp is directly in series with the transmitter.
If it burns out, the transmitter is dead.  In the 425B network it was replaced with a 22 ohm resistor to maintain the overall impedance of the circuit. 

[Southernphoneman]

Ok, here is another test to try, now your receive (dial tone) will not be as strong and I only recommend this for test purposes. Bypass the equalizer by removing the 4 leads of your handset cord and connect red and one of the white leads together to terminal R on the 425A network, take the other white lead and connect it to terminal GN on the network, now take the black lead and connect it to terminal A on the network. Then test it and if it then works like it is supposed to then you know your equalizer has gone bad.

[G-Man]

Ok, here is another test to try, now your receive (dial tone) will not be as strong and I only recommend this for test purposes. Bypass the equalizer by removing the 4 leads of your handset cord and connect red and one of the white leads together to terminal R on the 425A network, take the other white lead and connect it to terminal GN on the network, now take the black lead and connect it to terminal A on the network. Then test it and if it then works like it is supposed to then you know your equalizer has gone bad.

"terminal A on the network"
       ??

[Southernphoneman]

Ok, here is another test to try, now your receive (dial tone) will not be as strong and I only recommend this for test purposes. Bypass the equalizer by removing the 4 leads of your handset cord and connect red and one of the white leads together to terminal R on the 425A network, take the other white lead and connect it to terminal GN on the network, now take the black lead and connect it to terminal A on the network. Then test it and if it then works like it is supposed to then you know your equalizer has gone bad.

"terminal A on the network"
       ??

Yes terminal A on the network, I tried it on my 1950 500 before recommending and it worked.

[NorthernElectric]

If it were mine, I would try a known good line cord and do a bit more to check the handset cord (ie. test all the leads with a meter or swap a known good handset and cord onto the phone) before moving on to the internals.

[rp2813]

Wow -- if there was ever a doubt about the level of dedication among the membership here, the number of quick replies this subject has received should erase them all!

You'll have to excuse me, as I've been on Flexeril for some serious back pain that started yesterday.  One thing I failed to consider it that the other phone I tested is a cordless.  Not just a cordless, but a cordless extension from the "mother" cordless, and that's where its dialtone comes from.

I've checked another known good phone, a 2500, almost back to the jack in this room and it's dead too.  So, this appears to be a wiring problem.  The jack is behind a file cabinet, and with my back the way it is, I'm not going to attempt to move it.

I'll report in after I've been able to get the cabinet out of the way and have traced things back to the source of the problem.

I'm pretty sure this has become a station wire issue rather than an equipment problem.

Thanks for the good information.  If resolving the wiring trouble doesn't help (coincidences do have their way of occurring), I may have to refer back to your recommendations.

[poplar1]

If a phone had dial tone before, and also was ringing on incoming calls, then the first thing I'd do on a phone that no longer had dial tone would be to call it (from another line or cell phone). If it doesn't ring, then it's probably not a bad equalizer, handset cord, or receiver. Rather, it's probably either no dial tone at the wall jack (which turned out to be case here), or an open mounting cord (line cord).

[rp2813]

SPM, if it comes down to the phone being the problem, I'll try your test as suggested.

I'm not interested in permanently wiring this phone like a J/K model.  I was using an 8/'51 500 T on my desk for a while and the sidetone became too annoying.  I'll only bypass the equalizer on a test basis if other remedies don't help, but I wouldn't want to use the phone that way for any length of time.   Maybe if I was in an outlying area sidetone wouldn't be as bad.

G-man, as I understand it, SPM's method wouldn't be a permanent fix or bypass like the one you provided.  He advised it would produce only a faint dialtone, but at least it would peg the equalizer as the culprit.

This 10/50 appears to be so low mileage that I'm inclined to think and hope I only have a wiring problem.

[rp2813]

Well, everybody was getting upset over what turned out to be nothing major.

Bad back be damned, I fought the file cabinet away from the wall (it's on carpet) and pulled the plug out of the jack.  The jack is a flush wall-mount with a switch plate sized surround.  I unplugged the modular connection and plugged in another lead, which gave me dial tone.

I couldn't find anything noticeably wrong with the existing lead, and it seemed to be secure when I unplugged it, so I plugged it back in and connected the phone to the other end of it, and this time it produced dial tone.

I can only assume that a few days ago, some fiddling around with AC extension cords that pass by the jack may have disturbed something.  I'm leaving the file cabinet further away from the wall than it was so the jack isn't disturbed and I can easily access it if the problem presents itself again.

Thanks to all who offered advice, and I'm sorry that it resulted in some disagreement.  The wiring diagram provided further up-thread may be helpful in the future to anyone who finds they have a bad equalizer.