AE50 Restoration Progress

[dumb_old_guy]

I have had this AE50 a couple weeks, and have posted a few pictures in another thread asking about the (missing) dial cover.
Wanting to keep a record in order, I will redirect those posts to here so that I can keep a running pictorial thread of its restoration progress. There was a lot of pitting in the bakelite on the handset. I wonder if a user sprayed it with disinfectant on a regular basis and that is what attacked it(?)

cheers
Rob

Before pictures:

[dumb_old_guy]

The handset and ringer are done. The handset was tedious to clean up--especially the heavily rusted transmitter cartridge.
Also, the ringer is for 50Hz, so I had to cut slots in the centering spring to "soften it up" and move the clapper weight outboard a little to ring at our standard 20Hz. It rings loud and clear on 20Hz now. I redrew the schematic label inside the phone to make a new sticker, too.

The ringer is shown before and after.

More pictures as I make progress...

cheers
Rob

[Dan/Panther]

They look like NEW parts. I just love the way old phones clean up. I think it's the first Hobby I've ever been involved in where even a New Member can get good results and not have to spend a fortune or months of hard work.Examples like this encourages them. Makes it more enjoyable, and easier to get knee keep in.

D/P

[dumb_old_guy]

Thanks D/P!
It helps that the old Telco owned equipment is built so well. They clean up without falling apart (usually).
I have a lot to do yet. This will take a while, but it is enjoyable fixing up something worth fixing.

cheers
Rob

[HarrySmith]

Looks great, nice work. How did you get the ringer coil covers & label so nice? The ringer wires color is very bright, did you dye them? Also I would be interested in the modifications you made to the ringer to get it to ring.

[Mr. Bones]

Beautiful, meticulous restoration work!

I drooled after an AE50 for long many years, until I finally found a good deal: 2 nice ones for what I was willing to pay for just one.:

http://www.classicrotaryphones.com/forum/index.php?topic=8582.msg99792#msg99792

Keep up the great work, and best regards!

[dumb_old_guy]

Looks great, nice work. How did you get the ringer coil covers & label so nice? The ringer wires color is very bright, did you dye them? Also I would be interested in the modifications you made to the ringer to get it to ring.

Thanks, Harry, I used hobby type enamel paint (Testors, etc.) because I can have a lot of different colors to mix and match.
I thin it fairly watery with lacquer thinner. The cloth covered wires get a wipe with alcohol to clean them of wax. When they are dry, I run the thinned color paint down them with a cotton swab, then wipe off the excess with a paper towel. I hang them to dry for a few hours, then wipe them with  coat of Armor All, or similar. (Been doing it for years on vintage tube radios.)

The label is a inkjet reprint on Avery white sticker paper with a couple of light overcoats of satin lacquer spray. 
The coils are first cleaned, (painted in this case) then clear-coated with gloss lacquer. When dry, the sticker is applied and the whole thing is gloss coated again. Paper works instead of sticker paper, but them you have to mess with glue. If you use plain paper for the labels, it must be clear lacquered both sides (several light coats so the ink doesn't run) to fix the ink in place and keep the glue from soaking into, and wrinkling, the paper. Rubber cement has less tendency to do that than water based white glue. But it is always best to apply a few coats of clear lacquer to any inkjet printing before using it as a label. Clear enamels will work, too, but lacquer dries quicker and generally is not sensitive to recoat times.

Party line ringers are tuned to resonate sharply at their factory frequency. Many are tuned both mechanically and electrically, (Electrically with a capacitor size chosen for the coil inductance and desired frequency.) but I think this one was just mechanically tuned. In any case, there is a bit of scientific trial and error involved.
Fortunately I have a digital function generator I use to drive one channel of an old stereo amplifier, then to a step up transformer, so I can generate any test frequency at up to 125 volts or so. I can't say how to modify any given ringer, but in this case, I "softened" the clapper spring by cutting slots into the sides of it with a Dremel tool cutoff wheel. That made the clapper's natural frequency lower, and in general made it easier to move back and forth.
The clapper spring on this particular ringer is a flat piece of spring steel opposite the bells.

cheers
Rob

Beautiful, meticulous restoration work!

I drooled after an AE50 for long many years, until I finally found a good deal: 2 nice ones for what I was willing to pay for just one.:

http://www.classicrotaryphones.com/forum/index.php?topic=8582.msg99792#msg99792

Keep up the great work, and best regards!

Thank you, Terrence! Nice find there on the link.

cheers
Rob

[dumb_old_guy]

I ended up finding some leakage in the condenser (capacitor) pack, and so I had to open the can and "restuff" it with new capacitors--a 2uF and 4uF. The original was .08uF and 4uF for the 50 Hz ringer. Of course the can was repainted after soldering the top back on.
Also, the dial face was worn and the number 1 was almost completely gone so I made a new decal for all the numbers and letters to go onto the freshly painted dial. 6 coats of clear lacquer were then applied. The dial mechanism, hook switch assembly, and all of the terminal board were completely cleaned, shined up, and lubricated as needed. The wiring was also re-laced with new waxed cotton (black) cord.

cheers
Rob

Some new pictures:

[unbeldi]

An 80 nF capacitor was used by AE for all ringers with frequencies from 42 Hz and higher.

How did you decide on the value of 2 µF to replace the 80 nF capacitor?

2 µF is extremely large for a ringing capacitor, and represents a rather large load on the telephone line.  Fortunately, the AE 40 and 50 are designed to disconnect the ringer when the handset is taken off-hook and this prevents loss at audio frequencies during the call.

When off-hook, the capacitor however is switched for use as a radio frequency filter and spark quencher across the dial pulse contacts. 2 µF is also much too large for this purpose and jeopardizes the proper operation of the dial.  I bet that your dial pulses are highly distorted.

[dumb_old_guy]

My bad. I mistyped. I used a 0.2uF for the ringer cap., not a 2.0 Sorry.

cheers
Rob

[unbeldi]

Thanks for clarifying that.

For comparison, here is a table of the capacitor values that AE used for ringing at the various frequencies (from the indicated GSP).