Blow Dryer Success on E1 Receiver Cap But . . .

[rp2813]

I finally picked up a blow dryer at the thrift store yesterday and first thing today I took the receiver assembly off my E1 to take a shot at removing the cap.  After heating up the cap for a couple of minutes I took a strap wrench to it and with gentle but firm pressure, it broke free and spun off easily.

But, I was expecting to find problems with the diaphragm since the reception quality is very hollow and squawky.  Instead, I found the diaphragm to be in great shape, smooth and shiny black on the exposed side, and clean brass on the other.  The only thing I notice different from pix of a 557B element I've seen on OPW's site is that the center portion of the element on mine has a purple coating on it.

Now I'm not sure what to do.  Does the receiver need to be replaced, or is it perhaps my subset that's at fault?  It's vintage 1931 with wood terminal blocks, and may not be anti-sidetone.  Could that be my problem?

I've attached a picture of the element.  Comments and advice are welcome.

[rdelius]

Try turning the diaphram over to see it it makes things louder.Make sure magnet pole pieces are clean.
Robby

[LarryInMichigan]

The receiver looks to be in very good condition.  Make sure that all surfaces are clean and flat.  Any dirt or oxidation on or against the diaphragm will affect the sound.  Also, make sure that the receiver cap tightens properly over the edges of the diaphragm.  Anything which reduces the ability of the diaphragm to vibrate will reduce the volume from the receiver.  Be very careful not to bend the diaphragm.

Larry

[rp2813]

Thanks guys. 

I cleaned everything up but it needed very little of that.  I reversed the diaphragm and made sure the cap was tight against it.

No change.  It sounds the same with diaphragm flipped over.

My test call was to a number that would provide a known telco "We're sorry" recording.  Probably a tough job for a 557B to handle, but I made a subsequent call to the same number on my 1950 500 with 10/50 dated U1 element. 

With the 557, the "S" annunciations were muffled (she could have easily been saying "We're forry"),  but on the 500 with U1, the "S" sounds were distinguishable.

Am I being too particular?  My big complaint about the 557 is that when I'm speaking with someone who is on a cell phone, the 557 isn't clear enough to overcome the host of inferior characteristics associated with cell phone transmissions.  The same can be said of conversations where the distant party is on a cordless or speaker phone.  Am I wrong in thinking a 557 is capable of doing better?  Is this as good as it gets?

[Adam]

Don't forget, the sound has to go all the way back to 1931 and then come back again.

[LarryInMichigan]

The old metal diaphragm receiver will never sound as good as a newer type, but it should not sound that bad.  I have several handsets with receiver elements of that type which I use frequently, and I do not think that the sound quality is so bad on them.  Have you tried connecting a newer handset to this phone to determine if the problem is in the phone?  Are all of the parts in your receiver tight, or do any of them rattle?

Larry

[rp2813]

No rattles in the receiver or anywhere in the handset. 

I've got some spare F1's I can install so will do that and see how it sounds.

Replacement 557's aren't that expensive through OPW and I presume they would have been tested for proper performance, so I'm may take a chance and order one if the F1's reception is good.

This 557 of mine seems to have some roughness in the threads for the spacer ring, and the ring's threads have gotten chewed up in some spots.  It might be just as well if I order a replacement receiver and another good ring while I'm at it.

I'm going to try an F1 now and will report on results.

[rp2813]

The F1 was slightly better, but not dramatically.

The subset is a 554-C that appears to be all original from 1931.  

I am remembering now that up until I ordered the F1 transmitter adapter for the E1 handset perhaps 3 or 4 years ago, this phone was outfitted with an F1 handset and while volume was low, it was fairly clear.

I noticed the hollow squawky characteristics after attaching the E1 once I had received the F1 transmitter adapter.

I don't know if that rules out the subset or not.  The F1 handset I just tried out is not the same one as was on the phone in the past, so perhaps it has its own issues, having been in a box in the garage for many years.

[LarryInMichigan]

Have you cleaned all of the contacts and spades?  Dirt or oxidation could make a difference.  Also, crimping the spade connectors over the wires might help.  I have found that doing this improved the sound on some of my phones.  An air gap or layer of dirt or oxidation in a connection will act like a capacitor (and possibly also a resistor), and affect the sound.  It is also possible that bad conductors inside the cords and/or broken insulation could be causing problems.

Larry

[dencins]

Make sure wiring is not reversed.  I had this on a F1 and the reception was faint.  Make sure red, white and black are to the correct terminals.

Dennis

[rp2813]

I made sure all handset cord connections were color matched when I re-attached the E1 after testing with the F1.

Everything is super clean and there is no oxidation anywhere. 

I've been thinking about buying a crimper so once I have one of those I'll use it on both ends of the handset cord.

I have this feeling that if I got a replacement receiver element from OPW it might not provide any improvement.   Maybe it's just me, and this is indeed as good as it gets.

I noticed that with the F1, the loud clicks at the beginning and end of fingerwheel travel and with switch hook action were not as loud and hollow sounding as they are with the E1.  Might that provide additional clues?

[Phonesrfun]

The thread has been split but I will reply here.

As to the bad accoustics of the 557 receiver, I would try another receiver to be safe.  I cannot really tell much of a difference between a 557 and the F handset's HA1.  Particularly, the 557 will sound a bit tinny compared to a more modern receiver, but the level of distortion you describe is not what a normal 557 will do.  Swapping out the transmitter won't do anything to help, nor the inductor in the subset.

When you hear the popping, which subset are you using?  You mention a 554C.  I am not familiar with a 554, but I am familiar with a 534 and a 584.  Photos of the inside would help greatly at this juncture.  If it is the 534, that subset uses a single capacitor that serves a dual purpose for both the receiving cap and the ringing cap.  Those will pop (harmlessly), and the only solution is to put in another cap for the sound cap.  As to a 554C for message units, I have not seen a schematic of that.  If anyone has that, I can tell if the message unit feature is interfering, but I doubt it, and message unit equipment came along much later in life anyway, as far as I know.

Cheers,

[rp2813]

I'm not sure yet, but I may have conductor configuration issues between the stand and the subset.  I'll have to look into that before giving up on the current receiver element.

[rp2813]

OK guys, I started a thread over on the general discussion board re: the 554 subset and as a result it appears the wiring of my rig is nothing like it should be, and the actual receiver element is looking less like the source of the problem.

I'm going to focus on that, and will probably switch out the 554 with a 634, so for the time being the ongoing discussion will be taking place over in the other forum.

Thanks for all of the input here.  It has helped me through a process of uncovering problems I hadn't realized existed with my D1.

[rp2813]

It's fixed!

I swapped out the 554 subset for the 634, and followed Bingster's diagrams for wiring up a 202 for dial service.

The reception quality is much more clear, and the loud clicking at the beginning and end of fingerwheel travel has been greatly diminished to a more normal and acceptable level.

Test calls have been completed to make sure transmission quality is adequate.  I think this phone is ready to use for relaxing calls either placed or accepted from the comfort of the guest room bed!

Thanks to all who responded here.  It appears the 557 element is working properly and that wiring and subset issues were the real problem.