Phone Marked "L/M 500*" Won't Break DT or Ring

[rp2813]

Found a beige-cased & black bottomed 1963-based 500 at the thrift store today.  Very clean except for the patented rusty foot syndrome.  The wiring is weird, has what should be the L1 connections all on "F" (network is 11/63) but before I start with trial & error I thought I'd check here first to see if the asterisk or L/M designations mean anything that will present problems.

Dial is a 1967 9/C with 51 color code.  The case is 1978 and a more rosy beige than my 1963 beige one.  The phone has been modularized but I thought this might be a good parts phone if nothing else.

It won't break dial tone and won't ring.  Audio seems like it's not as loud as it should be.

Any advice on how to resolve these issues would be appreciated.

Thanks,

Ralph

[bingster]

Paul Fassbender's site has this to say about the L/M:

Single line w/ A-lead control for 1A2. 4-conductor mounting cord and terminal strip installed below dial.  Originally used in applications where the ringer circuit had to be brought out through the munting cord.

Now, what all that means, I haven't a clue.

I'd venture a guess, though, that if the parts are standard parts (C4 ringer, standard network, etc.), then you could probably rewire it to conform to standard C/D wiring, and have it work fine.

[Steve K]

The L/M series was designed for a KSU system.  The ringers could be wired across the line for Central Office ring current but many were connected to a common ring circuit generated in the KSU unit.  Yes, it can be easily rewired as a standard 500 phone.

[rp2813]

OK, thanks guys.  I was going to try the typical 500 wiring scheme but thought it best to check here first before I got started. 

Also, I pulled the transmitter to check its operation, so changed it out with another of my 500's that's connected, and wow, it really sounded loud and clear without any fuzziness at all.  In fact, it almost seemed like a higher than average sidetone situation due to the clarity, I guess.  Transmitter is dated 1963 with no additional test or refurb dates.  I'm tempted to install it in my 10/50 that currently has a 1955 transmitter.

So is 51 the right color code per the dial on this phone?  I know there was a post a while back with all color codes listed.  Maybe that one is a candidate for the Technical Reference section?

Ralph

[Dan]

51  is moss green

http://www.paul-f.com/color.htm

[rp2813]

Interesting with the moss green color code.  Maybe with phones used commercially they weren't as fussy about matching dials and cases, or at least maybe by 1978 they weren't, which is what all beige components on this set are dated and when I presume it was modularized.

[rp2813]

Well guys, I'm giving this a bump because I tried to configure the wiring for a regular 500 and now the phone is dead. 

I compared it to a couple of properly wired 500's and found that, unlike the other two, this set has only 6 conductors from the hookswitch instead of the 7 that I counted on the two good phones.  The missing conductor is the one that goes to terminal F, which is where the L2 line and black ringer leads were connected originally.  So right now the F terminal only has the blue dial lead on it.  It appears there should be a brown & white (ish) lead from the switch also connected to terminal F along with the dial lead, but there is no such lead coming out of the switch.  All other switch leads on this phone are connected to the proper terminals.  Strange that it's missing one altogether.  And the phone did at least provide a dial tone with the wiring scheme it had before I messed with it.  It just wouldn't break it when dialed.  Seems I've taken a step backward in this process now.

Any suggestions?  I've never worked on a hookswitch assembly.

Ralph

[Steve K]

Ralph:

The only lead missing on the L/M switch is the slate colored lead that connects to L2 with the slate-yellow lead from the switch.  The slate lead is not needed for the standard C/D configuration.   The slate-white lead that goes to F is part of the contact paired with the slate-green that goes to L1.  Recheck your connections, you should have all the wires from the hookswitch that you need.

Steve

[rp2813]

Hey Steve, thanks!  That worked--I pulled the SL/W lead from L2 and put it on F with the blue dial lead and now I get dialtone again and can make calls.    However, it won't ring.  I have the usual configuration from the ringer:  R=L2, W=K, R/W=A and BK=L1.  This is a 425E network.  Should the ringer wiring be different from the way I have it?

Thanks for any additional advice. 

Ralph

[bingster]

Black from the ringer actually goes to the "G" terminal.  Once that's done, if you don't get a ring, try connecting the yellow and green wires of the mounting cord at the wall end.  In other words, at the jack, connect red under the red screw and connect green AND yellow under the green screw.

[rp2813]

Hey Bing, moving the black lead to G didn't get it to ring.  Since I haven't decided on where I'll connect this phone, if I even connect it at all, I'll wait before trying to connect Y and GN on the wall jack itself.  I'm leaving on vacation day after tomorrow so time is short for any further trial & error, but I'll either revive this thread or start a new one after trying with the jack wiring.

Interestingly, a 7/54 500 I just obtained recently had the black ringer wire on G and I had to move it to L1 to make the phone ring.  I presume that since this phone I'm working on has the L/M designation, that is what's driving the suggestion to place the black wire on G.

Thanks for the help thus far.  At least the phone can dial out now.

Ralph

[bingster]

Moving the black wire to G is based on the C/D diagram, rather than L/M.  But no worries, we'll get it eventually.  Have a great vacation!

[rp2813]

It rings!

I decided to go back to the same configuration as my other ringing 500's and put the black ringer lead back on L1.   I noticed the lead was seriously bent at the spade and almost looked frayed, so I straightened it out and was going to try jiggling it around to see if that changed anything.  This meant leaving the case off when testing.  I had been putting the case back on when I had tested before. 

So, with case off and black lead on L1, I tried it and could hear faint clicking like it was trying to ring but the striker wasn't moving.  Went back to G with the lead just to be sure, and no clicking at all with that arrangement.  Back to L1 and jiggling the black lead; no change, just clicking.  I checked the tensioner and it was in the same position as on my "control" phone.  I figured it was worth trying to reposition the tensioner from the centered position it was in, tested again and got a clear and loud ring from it.  So it was the tensioner all along and L1 is the correct connection for the black ringer lead.

Now I need to figure out how to get the clear fingerwheel off.  I know there was a recent thread with this info.  I can't get the clear wheels off of either of my phones that have them, and this phone I just got ringing appears never to have had a number card.  It's in such perfect shape, I'm thinking it never got deployed at whatever business it belonged to.  I think I'll connect it in my den once I get a number card in it.

Thanks for all the help--this one's a keeper now!

Ralph 

[bingster]

It's nice when you get one to ring, isn't it?  Here are instructions for removing the fingerwheel:

http://www.porticus.org/bell/pdf/itt_k500_fw_removal.pdf

[rp2813]

Thanks for the fingerwheel info.  I knew there was a paper clip involved but I was inserting it in entirely the wrong place. 

Ralph