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Can a 554C Subset Be Rigged to Work With a D1?

Started by rp2813, October 12, 2015, 12:16:42 AM

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rp2813

I inquired about this in another thread started by unibeldi about wiring on the 554C sidetone subset, and we decided any further discussion needed to happen in a new thread.

If you search for discussions on the 554C, you'll find one I started a few years ago, but there seems to be more knowledge on the boards here now with regard to this particular subset.

I'm facing a need in the near future to use my 634BC subset with a 201A (with F1 handset) I've purchased for my workshop, providing I can make the D1 set function properly with the 554C, which is in beautiful shape worthy of open display (something that can't be said for my 634).

I have used the 554C with my D1 in the past, but the reception quality was poor (an "S" sounded like an "F"), squawky, and sidetone was bothersome.  When I hooked the D1 up to the 634BC, the improvement was dramatic.  I've been using it that way ever since.  What I don't know is whether my 554C retains any of its party line wiring scheme, and if that might be part of the trouble.  I was getting loud clicks in the receiver with any switch activity, including at the beginning and end of finger wheel movement.

Now that I need a subset for the 201A, I'd like to put the request out there again for guidance on whether it's possible to get the same results from a 554C as with a 634BC, and if so, how the subset and switch/dial wiring should be configured.  My D1 has a 4-conductor lead between the set and the box.

If there's no way to match the transmission and reception quality of the 634BC subset, then I'll use a 302 base until I find a deal on a 634 or 684 box.

Thanks for any instructions, suggestions, or redirection to a diagram I may have missed that provides this configuration.
Ralph

poplar1

#1
If you were hearing loud click when hanging up (or slowly pressing down on the plunger), the 554C subset was probably miswired or defective.  Check to make sure the subset is wired like the 554C with the 51AL in unbeldi's diagram. (Reply #2--)
http://www.classicrotaryphones.com/forum/index.php?topic=12355.msg143472#msg143472

Your 202's mounting cord would connect to the subset the same as the 51C 51-AL: green to GN, red to R and yellow to L2-Y.  The black wire from the 202 would not be connected in the subset; thus, you would be using the 202 as if it were a 102 -- that is, as a sidetone set.

Ironically, both the 554C and 634BC were used on 2-party message rate lines.
"C'est pas une restauration, c'est une rénovation."--François Martin.

rp2813

#2
Well, I really tried to interpret both diagrams, but now my head just hurts.  They both seem to be schemes for party line service, so unless I'm missing something, I don't see how that applies to single line service.  This could simply be attributable to my lack of expertise on circuitry.

One instruction advises to "reverse" the red and yellow conductors to reduce sidetone.  Maybe I'm being too literal, but I don't see how "reversing" a conductor will change anything.  That appears to be Bell System terminology, but I'm wondering if they meant "transpose" instead.

It's late and I'm not at my best, so I'll try again tomorrow with the 554C opened up to compare with the diagrams, and then maybe it will (begin to) make sense.



Ralph

poplar1

#3
554C used for single line (bridged) service:

Ringer:
Red-----> L1
Black----> RR

Ringer capacitor:
Yellow----> L2Y
Double Red---> RR

Talk capacitor:
Connect to L2Y and C

Line:
Tip(green)--> L2Y
Ring(red)---> L1

Mounting cord from phone:
Red------> R
Green----> GN
Yellow----> L2Y
Black-----> tape and store

Nothing connected to B terminal or GND terminal
"C'est pas une restauration, c'est une rénovation."--François Martin.

unbeldi

#4
.

unbeldi

#5
.

unbeldi

#6
.

rp2813

#7
Thanks to both of you for the thorough explanations.

It's easiest for me to work with poplar's typed out scheme, as I don't have the electronics knowledge to decode a schematic.  Some time ago I printed a copy of a color diagram for a 634/684, I think created by bingster, which is easy to follow, and that's what I used to get the 634BC working with my D1.  I'll check that against the information that's been provided elsewhere in this thread. 

Two terms I'm not familiar with for the 554 are "ring capacitor" and "talk capacitor."  The only two things on the 554 that have conductors are the ringer coil (R & BK) and a large silver box -- shaped like an oversize stick of butter -- which has four conductors, two yellow and two black.  I can see that one set of wires is configured as poplar suggested for the talk capacitor, so it appears the ring capacitor uses a black instead of double red, along with yellow.  The yellow is currently connected to B, so that's incorrect per poplar's advice.

The ringer coil's black goes to RR, but the red is on a lone unlabeled (dead?) screw below the R terminal.  I think this could be because I didn't want this box to ring.  If there's a better terminal to place the red lead to keep the ringer silent, please advise.  Perhaps the ring capacitor's yellow conductor on B is another way to silence the ringer?  Or create worse sidetone?  ;-)

Otherwise, per poplar's directions, it appears only the ring capacitor's yellow conductor needs to be moved from B to L2Y, and ringer coil's red to L1 (if necessary) to accomplish this scheme.

I'll check the schematics again and try to make sense of them by interpreting them against poplar's typed out scheme.  Once I'm sure of the best possible configuration to attempt to reduce sidetone and perhaps reception quality, I'll hook the box up to the 554 and report in on results.
Ralph

unbeldi

#8
.

rp2813

Thanks for the additional explanation.  I'm slowly figuring out how to decipher the schematics, and will pose this question to see if I'm understanding them correctly:

In the upper schematic in reply #5, is it suggesting that I take the black lead from the ringer coil and terminate it on C instead of RR?
Ralph

unbeldi

#10
.

rp2813

OK, I was referring to the post at (EDT) 8:54:32 AM today, which provided a possible sidetone reduction strategy.  That's the schematic that I wondered if I was interpreting correctly as taking the black ringer coil lead off of RR and placing it on C.  I looked at the 102 vs 202 schematics and couldn't begin to decipher them, so went back to the seemingly simpler one in this thread.

I guess I'm not getting it as far as how to read a schematic as opposed to a layman's diagram.  Per the most recent post, it seems the subject schematic deals with the red ringer wire and not the black, and wants it placed on RR instead of L1?  If that's the case, my logic is all wrong about what the schematics are attempting to convey, as well as in thinking the ringer wiring has no effect on sidetone.  I apologize for my deficiencies in the arena of electronic theory.

What I want to accomplish is single line subset wiring that 1) has the best chance of reducing sidetone, and 2) disables the ringer.  Perhaps this is best explained in text form, now that I have the subset configured to match poplar's written instructions for single line service, which I presume will also serve to eliminate the loud clicks from the switch.
Ralph

unbeldi

#12
.

poplar1

Quote from: rp2813 on October 12, 2015, 03:10:52 PM
Thanks for the additional explanation.  I'm slowly figuring out how to decipher the schematics, and will pose this question to see if I'm understanding them correctly:

In the upper schematic in reply #5, is it suggesting that I take the black lead from the ringer coil and terminate it on C instead of RR?

Reply #5 shows a 534A,  which does not have an "RR" terminal, since there is no "double red" conductor going to a 203 or 51-C phone. The 534A has only one capacitor (condenser), which is used for both the ringing circuit and the talking circuit.
"C'est pas une restauration, c'est une rénovation."--François Martin.

rp2813

Thanks for putting up with me this far . . .

I'll take some pictures and post them here later on.  One of the 554C subset after following poplar's instructions, and one of the switch and dial as currently configured with the 634BC.
Ralph