Author Topic: Snagged my first Mercedes Dial on an AE 21 Candlestick off of eBay  (Read 9515 times)

Offline HarrySmith

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Re: Snagged my first Mercedes Dial on an AE 21 Candlestick off of eBay
« Reply #90 on: October 06, 2016, 11:46:03 AM »
Very creative, nice work!
Harry Smith
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Offline TelePlay

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Re: Snagged my first Mercedes Dial on an AE 21 Candlestick off of eBay
« Reply #91 on: October 07, 2016, 12:21:17 AM »
Very creative, nice work!

Thanks, Harry.

Just finished wiring up the stick (transmitter and hook switch to the terminal strip) and all went well. Plan was to clamp two hemostats on the repaired leafs half way between the tip and the butt soldered joint to act as heat sinks when attaching the wires to the ends and that worked well.

To get the wire I was using correct on the terminals, I put a 1/4" of colored shrink tubing on each end. Worked well. Certainly not original factory but it works and no one will see it once it's buttoned up.

Next steps are wiring the dial, the subset and hooking everything together.
« Last Edit: October 07, 2016, 12:38:15 AM by TelePlay »
            John . . .

              

Offline TelePlay

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Re: Snagged my first Mercedes Dial on an AE 21 Candlestick off of eBay
« Reply #92 on: October 07, 2016, 04:09:52 AM »
Hard to put something down when it's going together.

Wired up the dial and installed it. Worked out well. Never done this before so I did it to look good, not match factory spec. After looking at the image, had to check the wiring and each lead off of the dial has at least 1/16" clearance from anything else metal.

Only problem was stripping cloth covered wire - anyone have a good way to do it?
« Last Edit: October 07, 2016, 04:13:04 AM by TelePlay »
            John . . .

              

Offline Pourme

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Re: Snagged my first Mercedes Dial on an AE 21 Candlestick off of eBay
« Reply #93 on: October 07, 2016, 06:40:30 AM »
Workin on phones at 4am....It is looking good, John.
Benny

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Offline TelePlay

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Re: Snagged my first Mercedes Dial on an AE 21 Candlestick off of eBay
« Reply #94 on: October 07, 2016, 04:51:53 PM »
Workin on phones at 4am....It is looking good, John.

Yeah, when I get going on something, sleep takes a back seat.

Wired up the subset to include a 101A coil making the set up AST. I sure am glad they made those wood boxes with a removable back.

Only thing left to do is add the three external cords, and plug it in. One thing missing in the subset is the talk capacitor. I decided to take the 5 uF tin out to make room for the 101A and will add a capacitor between posts #5 and #6 (the two right posts) in the box. #5 is the "C" output from the coil to the phone through the cap. Since the coil, transmitter and receiver are "new" to the set up, I can adjust the capacitance to get the best results and then solder that value in place.

These are not the best photos. They are intended to show the wiring progress from as received to finished and the two components next to each other. Will take time taking the final photos once the external cords are attached.
            John . . .

              

Offline TelePlay

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Re: Snagged my first Mercedes Dial on an AE 21 Candlestick off of eBay
« Reply #95 on: October 10, 2016, 05:15:35 PM »
IT WORKS!

Went with the wiring diagram below using new cloth cords, a 2 conductor receiver and 4 conductor subset. On first fire up, rang and both transmit and receive worked. But going off hook to call out was intermittent and it would not dial out, but did produce loud pops.

Wiring was per diagram. But, found two problems. First was a bad spade lug on one of the shunt springs (open circuit bad) and the fiber spacer used to open and close the pulse springs was out of position - stopped with the pulse springs open.

Fixed both issues and it works great. Still have to play with the talk capacitor to get the best results and button it back up after partial disassembly.

Only question is I get a pop in the receiver when I lift if off hook. Any suggestions?

This was quite a project. Learned a lot (this was my first major restoration - and it was turning a gutted lamp into a phone) that will come in handy next time.

"After" pictures to follow in a few days.
            John . . .

              

Offline TelePlay

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Re: Snagged my first Mercedes Dial on an AE 21 Candlestick off of eBay
« Reply #96 on: October 10, 2016, 07:45:38 PM »
Quick question.

When dialing out on the stick with the receiver to my ear, I get a lot of mechanical feedback from the dial working on the metal base attached to the metal stick attached to the metal cut attached to the metal transmitter.

Was there a rubber gasket between the dial and the base or is that just the way it's supposed to sound, or sounder 95 years ago?
            John . . .

              

Offline LarryInMichigan

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Re: Snagged my first Mercedes Dial on an AE 21 Candlestick off of eBay
« Reply #97 on: October 11, 2016, 04:31:00 PM »
To remove the finger wheel, first remove the finger stop, then gently twist the spring at the end of the red arrow (in the picture below) a bit so that it will slide out of the groove in the post.  You should then be able to remove the finger wheel by pulling it up from the dial.  To remove the number plate, you need to carefully bend the three copper wires at the green arrows upward so that they will not hold the plate to the dial housing.

Larry
« Last Edit: October 11, 2016, 04:35:49 PM by LarryInMichigan »

unbeldi

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Re: Snagged my first Mercedes Dial on an AE 21 Candlestick off of eBay
« Reply #98 on: October 11, 2016, 04:44:04 PM »
Quick question.

When dialing out on the stick with the receiver to my ear, I get a lot of mechanical feedback from the dial working on the metal base attached to the metal stick attached to the metal cut attached to the metal transmitter.

Was there a rubber gasket between the dial and the base or is that just the way it's supposed to sound, or sounder 95 years ago?

I have the same feedback on WECo stands as well. I would think it is typical for all dial desk stands.  I doubt that AE used any damping between dial and chassis either.
More effective than damping the dial/chassis contact would be to implement something at the perch/transmitter interface to dampen sound conduction into the transmitter assembly, because the switch hook causes similar problems, in fact all tapping and playing with the housing does.

Offline TelePlay

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Re: Snagged my first Mercedes Dial on an AE 21 Candlestick off of eBay
« Reply #99 on: October 15, 2016, 02:28:00 PM »
Okay, here's a technical problem that's beyond my current knowledge.

Was using the old 1.5 uF cap for the ringer in the subset. Ringer worked with my ring generator but not real well, kind of weak. The ringer has two 250 ohm coils and my meter does show 500 ohms across both coils.

I changed out the 1.5 uF cap for the old 5 uF cap (only room for one in the subset with the 101A coil added) and hooked the 5 uF into the talk circuit, a better use.

Put a 0.47 uF cap on the ringer and it did not work with either my Dsine 20 Hz ring generator or my 616 fed into L1 and L2 subset connections - normal use.

The ringer seems to be a SL AE ringer because it works just fine if I connect the ringer generator directly to the ringer terminals (no capacitor). But if I put the .47 cap in series, the ringer does not work with either the Dsine or the 616.

I put the 1.5 uF cap in series with the Dsine ringer circuit and the ringer rang weakly as it did before.

So, I got out my bread board and started to increase the capacitance. Ringer started to work fine with my Dsine when I got above 2 uF and continued to get a bit stronger with every 0.47 cap I added. Stopped at 3.9  uF.

But, while it rang with my Dsine attached to L1 and L2, the 616 still did not even vibrate the clapper at any capacitance. I checked the 616 with a 50's 500 and it rang just fine.

Question, what's going on and how do I fix it so the ringer works with my 616?


            John . . .

              

unbeldi

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Re: Snagged my first Mercedes Dial on an AE 21 Candlestick off of eBay
« Reply #100 on: October 15, 2016, 09:38:14 PM »
Hmm, 500 ohm total resistance for a bridging ringer is rather low.  But it is rather high for a series-ringing circuit, most of those ringers are only 100 ohms or lower.

I wonder what the A.C. current is without ringing capacitor, i.e. directly connected to your DSine generator.  If you can measure that, measure also the voltage across the ringer.  That gives us an idea of the impedance of the ringer, which will be higher than the D.C. resistance, which is 500 ohms.

With a 3-4 F capacity, I would guess that ringer to have at least REN 5.

A 0.47 F capacitor is indeed probably too small for a low impedance ringer like this.  My guess would have been between 1 and 2 F for a good value.

Hmm, is this ringer in any of the AE catalogs ?

Offline TelePlay

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Re: Snagged my first Mercedes Dial on an AE 21 Candlestick off of eBay
« Reply #101 on: October 16, 2016, 03:22:55 AM »
Hmm, 500 ohm total resistance for a bridging ringer is rather low.  But it is rather high for a series-ringing circuit, most of those ringers are only 100 ohms or lower.

I wonder what the A.C. current is without ringing capacitor, i.e. directly connected to your DSine generator.  If you can measure that, measure also the voltage across the ringer.  That gives us an idea of the impedance of the ringer, which will be higher than the D.C. resistance, which is 500 ohms.

With a 3-4 F capacity, I would guess that ringer to have at least REN 5.

A 0.47 F capacitor is indeed probably too small for a low impedance ringer like this.  My guess would have been between 1 and 2 F for a good value.

Hmm, is this ringer in any of the AE catalogs ?

Learned something about the 616 tonight. It will not send ring voltage down a line unless it sees more than 0.47 uF capacitance on the line, however it does that.

Once I raised the ringer capacitance over 1 uF, both my ring generator and 616 activated the ringer.

----------------------

As for measurements, the Dsine ring generator produced about 20 VAC measured at L1 and L2 and about 22 VAC across the ringer terminals.

With a 2.063 uF capacitor in place both the ring generator and the 616 rang the bell nicely. The ring generator produced about 22 VAC at L1 and L1 and the 616 produced 32 VAC at those terminals.

The old AE cap I have measures 1.568 uF and when used alone produced a weak ring. Adding a 047 uF cap in parallel gave a nice ring with both ringing devices. So, 2.038 uF was a good ringing capacitance. Increasing the capacitance did not make the ringer work noticeably better.

Now, checking the AE catalog from 1905, the first catalog in which I found a ringer that looks like mine and then based on the resistance of my ringer, it appears I have a frequency ringer. I did not see any part numbers on the ringer (the label was well worn) so I went with a picture comparison.

My coil resistance is 502.5 ohms which is half way between the 33.3/42 Hz ringers at 528 ohms and the 50/54 Hz ringers at 476 ohms. This ringer was found in the AECO 1934 catalog. First image below is the part numbers and the second is the image from the part number page next to my ringer, taken with and without flash. Since my ringer worked with my Dsine 20 Hz ring generator from the start, I always assumed it was a SL ringer. That reed and no bias would prove me wrong on that assumption.

The above stated info was take from page 38 of the TCI document: AECO Catalog 4055 - June 1934 ocr Tl  on their site. The page states this ringer was for their compact ringer box and the box I have is indeed compact.

So, it rings best at 20 Hz with a 2 uF capacitor in series. The calculation of VAC, Hz, uF and ohms is beyond me. So, just put in a 2.2 uF cap and call it a project?

Any other way of doing this without modifying the ringer itself?
            John . . .

              

unbeldi

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Re: Snagged my first Mercedes Dial on an AE 21 Candlestick off of eBay
« Reply #102 on: October 16, 2016, 08:41:56 AM »
Learned something about the 616 tonight. It will not send ring voltage down a line unless it sees more than 0.47 uF capacitance on the line, however it does that.

Once I raised the ringer capacitance over 1 uF, both my ring generator and 616 activated the ringer.

----------------------

As for measurements, the Dsine ring generator produced about 20 VAC measured at L1 and L2 and about 22 VAC across the ringer terminals.

With a 2.063 uF capacitor in place both the ring generator and the 616 rang the bell nicely. The ring generator produced about 22 VAC at L1 and L1 and the 616 produced 32 VAC at those terminals.

The old AE cap I have measures 1.568 uF and when used alone produced a weak ring. Adding a 047 uF cap in parallel gave a nice ring with both ringing devices. So, 2.038 uF was a good ringing capacitance. Increasing the capacitance did not make the ringer work noticeably better.

Now, checking the AE catalog from 1905, the first catalog in which I found a ringer that looks like mine and then based on the resistance of my ringer, it appears I have a frequency ringer. I did not see any part numbers on the ringer (the label was well worn) so I went with a picture comparison.

My coil resistance is 502.5 ohms which is half way between the 33.3/42 Hz ringers at 528 ohms and the 50/54 Hz ringers at 476 ohms. This ringer was found in the AECO 1934 catalog. First image below is the part numbers and the second is the image from the part number page next to my ringer, taken with and without flash. Since my ringer worked with my Dsine 20 Hz ring generator from the start, I always assumed it was a SL ringer. That reed and no bias would prove me wrong on that assumption.

The above stated info was take from page 38 of the TCI document: AECO Catalog 4055 - June 1934 ocr Tl  on their site. The page states this ringer was for their compact ringer box and the box I have is indeed compact.

So, it rings best at 20 Hz with a 2 uF capacitor in series. The calculation of VAC, Hz, uF and ohms is beyond me. So, just put in a 2.2 uF cap and call it a project?

Any other way of doing this without modifying the ringer itself?

I think, 2.2 F is quite reasonable for a low impedance ringer like this. I would leave it this way. I think until ca. WW-I a 2 F value was pretty standard for bridged ringers.
The REN value of the ringing bridge is probably between 2 and 3, closer to 3 than 2, not great by today's standards, but this is not a modern instrument.

I think you have found the reason for the somewhat weak response, in that it is a frequency-selective ringer.  The resonance point of these is off quite a bit from 20 Hz, so operating a 30-some or 40-some hertz ringer at 20 Hz is very inefficient and you can't adjust the resonance point sufficiently with capacitors anymore. At the resonance point the energy transfer from the electrical energy of the alternating current to the mechanical ringing action is at a maximum, so off-resonance the mechanical action rapidly decreases.  You can see this in the measurements I published here on the forum; included was a 1400 Ω WECo #8A ringer with a 1 F capacitor in a 534A subset.

unbeldi

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Re: Snagged my first Mercedes Dial on an AE 21 Candlestick off of eBay
« Reply #103 on: October 16, 2016, 08:48:52 AM »
The catalog table of ringer resistance values that you showed also explains the fact that frequency ringers were operated with much higher ringing voltages than straight-line ringers.  As the ringing frequency increases, the D.C. resistance is progressively lower, and therefor the ringer had to be operated at increasingly higher voltages to transfer sufficient energy. I think AE used up to 150 or 160 V for the highest frequency ringers (50 to 66 Hz).

Offline AE_Collector

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Re: Snagged my first Mercedes Dial on an AE 21 Candlestick off of eBay
« Reply #104 on: October 16, 2016, 12:57:37 PM »
Hi tried looking at the ringer in your earlier pictures of your subset and from what I could see it looked normal (SL) to me but these pictures are certainly a frequency ringer. Of course we can see the clapper now which was hidden before.

Sounds as though you've got it working though which is always good as you can keep the original frequency ringer AND it rings!

Terry
« Last Edit: October 16, 2016, 01:00:32 PM by AE_Collector »