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What am I missing?

Started by HarrySmith, May 21, 2011, 12:31:49 PM

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HarrySmith

OK guys, I need some help. What am I missing? I have a 554, 1960 vintage I am preparing to sell to a CL customer. I tested it yesterday and it worked. I took it apart to clean it and now it does not work, no dial tone. I checked the wiring half a dozen times. I pretty well know the 500/554 connections but I wrote down each wire as I took it off. I followed that list, I also checked against the diagram from the TCI library and compared to a working 500, everything looks good. I have attached some pictures below. In the second picture which is switch pileup in off hook position if I jump where indicated I get dial tone but, of course it will not dial. I removed the ringer to simplify things, I tested it independently and it works fine. Last picture is on hook. I must be missing something simple! Please help!
Harry Smith
ATCA 4434
TCI

"There is no try,
there is only
do or do not"

Adam

You didn't picture the back of the dial, which is part of the line path of the phone.

The contact of the dial which is wired to the green and blue wires should be "normally closed" and opens momentarily as the dial is pulsing. 

Short the blue and green wires to see if you get a dial tone. If you do, the dial is not making that "normally closed" contact correctly.
Adam Forrest
Los Angeles Telephone - A proud part of the global C*Net System
C*Net 1-383-4820

HarrySmith

You are right Dave, I did not include the dial as I was focusing on the switch pileup. I have checked the contacts before and they appear to be correct. I did try shorting the two wires with no change. I have attached a couple of pics in the hopes someone will see something. 
Harry Smith
ATCA 4434
TCI

"There is no try,
there is only
do or do not"

Adam

It's hard to tell 100% from the pic, but it looks to me like the contact on the dial that the two white wires are connected to looks closed.  This contact should be open when the dial is at rest.  This contact shorts across the receiver when the dial is dialing (not at rest).

To see if this is your problem, try removing one of the white wires from the dial on the network and see if you then get dial tone.
Adam Forrest
Los Angeles Telephone - A proud part of the global C*Net System
C*Net 1-383-4820

HarrySmith

Thanks again Dave. I checked under my magnified work light and the contacts are open. I tried disconnecting one white wire anyway with no luck. I also tried installing a known good dial with no luck either. I am getting very frustrated with this phone >:(
Harry Smith
ATCA 4434
TCI

"There is no try,
there is only
do or do not"

paul-f

It sounds like you're on the right track, Harry.

As has been pointed out, it sounds like something either shorted or went open before you reassembled the set.  Chances are something mechanical happened, rather than an electrical component failure.  Unless your eyes are a lot better than mine, I'd suggest using a butt set or continuity checker to trace the circuit -- not visual inspection.  You may not see a lot of the potential problems, but making sure the current flows from point to point will usually tell the story.

For example, I've found a few cases where spade tips have lost their contact with the "attached" wire.  Occasionally an intermittant problem will make itself known if you wiggle wires (which can be a lot faster than testing each one).  A hard open will be obvious if you look for a signal and it only appears on one end fo a wire.  Just take it one step at a time.

Good luck.
Visit: paul-f.com         WE  500  Design_Line

.

Phonesrfun

Let's ask about some obvious things that sometimes get overlooked.

First, I am assuming that you connected the line wire to L1 and L2.  Did you check the line cord wire on another phone to see if the line cord wire is working?  It could be that the connection in the wall is not making contact.  Always work backwards to check the obvious things.

Second, what about the handset.  Did you remember to connect the receiver wires to the receiver element inside the handset?  Make sure they are not touching each other and shorting out.  Also, check the contacts on the transmitter, just for good measure, although on a 554 you should still get a dial tone when the transmitter is out.

Finally, if all these things check out, when you have the phone off the hook and connected with nothing happening, take another phone off the hook in the house.  Check and see if the 554 seems to be connected and transmitting, even though the 554 seems to be dead.  If it is realy live, but just cannot "hear" anything, that might be a clue for further investigation.

-Bill G

Phonesrfun

One other thing.

There are two wires coming from the hookswitch that have spade tips.  One connects to the F terminal, and one connects to L2.  What colors are those wires?  Solid slate should go to L2, and slate/white should go to F. (later versions had the slate/white as solid white).

If these are reversed, the phone won't work.
-Bill G

Adam

OK.  Just spent some time on the phone with Harry.  The upshot is it's all wired properly and it still doesn't work.  Not only that, when connected to the line, the set throws a short onto the rest of the line.

I tried every combination of bypassing the switch hook I could think of, nothing helped.  I believe now that the only possible alternative is that the network went bad, or something fell into the inside of the network and is shorting something out.  (This is unlikely, however, since the inside of those networks is potted with that weird gewy stuff which doesn't conduct.  It's possible something is touching the undersides of the screw contacts, though.)

Although rare, I have had this happen to me before.  I had a 2702B Princess that refused to work no matter how I wired it.  I just eventually chucked that base and put the nice exterior parts on another base.

Perhaps this 554 just decided it was "his time".  He's now providing service in Western Electric heaven.
Adam Forrest
Los Angeles Telephone - A proud part of the global C*Net System
C*Net 1-383-4820

Phonesrfun

#9
Hmmm.  The fact that yesterday it worked, and after cleaning it, it quits working seems to point to something about the cleaning and reassembly that tripped it up.  Those networks just should not go out like that unless hit by lightning.

Oh well

PS:  What about the shank of the wire from the hookswitch that connects to L2.  Make sure it is not touching the soldered piece labeled P Q

-Bill G

HarrySmith

UPDATE!! It works!
After being on the phone with Dave and trying several different bypasses as he mentioned we decided the network was bad or shorted. He mentioned opening it up to make sure no foreign object got in to short it. I did open it and found nothing in it. I decided to plug it in for the hell of it while I had the network out and I got dial tone! I put it back in the case and nothing. I took it out again and moved a few components and connections toward the inside away from the case. Reassembled it and it is now working!
Thanks to all, especially Dave for your help and suggestions!
Harry Smith
ATCA 4434
TCI

"There is no try,
there is only
do or do not"

Phonesrfun

Now go wash the goop off your hands   ;D
-Bill G

Adam

#12
Wow! A network component was shorting against the metal case?  This is good to know, next time I have a "dead" network, I'll open it up instead of chucking it...  Makes you wonder about the wisdom of Western Electric to enclose the things in a little metal box.  Should have been bakelite or later plastic.

Excellent that you brought it back to life, Dr. Harry!  :-)

P.S.: Bill, about something possibly shorting P/Q, that was one of the several things we tried.  We removed both of the spade tipped switch hook leads and had them connected to nothing, and still using the network by connecting T and R to C and RR shorted out the line.  A short inside the network remained the only thing that made logical sense.
Adam Forrest
Los Angeles Telephone - A proud part of the global C*Net System
C*Net 1-383-4820

Phonesrfun

I guess it must have been one of those things that was always just waiting to happen.  Perhaps just the jostling from taking the phone apart and cleaning it was just enough to cause it to short out.  I guess you see something new every day!

-Bill G

HarrySmith

Yeah, I'm guessing it must have been close and my moving it around during cleaning managed to move it enough. I am still not sure which component it was but at this point it really does not matter!
Harry Smith
ATCA 4434
TCI

"There is no try,
there is only
do or do not"