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My odd antique store find today

Started by markosjal, January 23, 2021, 05:38:08 AM

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markosjal

Interesting, I think I can add the LED easily enough.

Is that a Zener diode?
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tubaman

#16
It is a zener but is integrated as part of the LED.
I'd guess a 2.1V zener for a red led to prevent the forward voltage going too high?
:)

dsk

 Markosjal's diagram does not have the Zener that tubaman's has.
My guess is that it will probably work with a LED and a reverse diode in parallell, it does not have to be a Zener.




markosjal

True, mine does not have the Zener, however it is ready to illuminate just like the WEs were with a Light bilb. I dso not believe there were ever LED illuminated rotary WEs though. Were rotaries always a light bulb?


I guess I may have to pull out an American ITT Rotary Trimline and see about lighting one up too.

I thionk i need to use the lowest power LED available though  and the voltage may vary. Note that my Red ITT Gondola is NOT regulated whereas the Chocolate Gondola IS regulated. This too may make a difference. Might be nice to develop a  one size fits all formula for this LED addition.
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dsk

Some time ago I was playing a little and just dug out a red and a yellow led from the drawer, put them in opposite direction and in a  short "extension wire".   I could plug in any phone and on led lighted up when I went off hook, the other on polarity reversal,  When ringing the led's was flickering. Thought I should kill the led's but no.  No warranty :-)

tubaman

I've just measured the voltages across my non-functional LED/Zener. One line polarity I get about 0.7V and the other about 3.9V. I assume this is the forward and reverse voltages of the Zener (the led part being dead).
I suspect just using a standard diode would not work as the LED would be trying to drop full line voltage in its forward direction, and that would not be good for it.
:)

dsk

Then you just keep that one and add a new LED across that.

markosjal

I put in a Bridge Rectifier (W02M) in that line then a 2.1V 20ma high output Red LED across the bridge rectifier.  (This LED that I had from a previous purchase in Mexico) https://www.steren.com.mx/led-ultrabrillante-de-3-mm-color-rojo.html

I then Plugged it into my ATA and checked voltage at LED to find 2.0V to LED.

Not sure how much the LED will tolerate before it cooks but I must say the red phone with red LED dial light is stunning.

I gotta go get some shrink tube to do it up right but plan to post pics!
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countryman

#23
You'd need to measure the current through the LED to determine if it's within it's specs.
But most ATAs put out 20mA at most and the LED is rated for that, so it won't get cooked.

markosjal

OMG! It is TRULY SATANIC!

Pictures do it no justice. It is RED RED RED!

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poplar1

Quote from: markosjal on January 25, 2021, 11:40:23 AM
True, mine does not have the Zener, however it is ready to illuminate just like the WEs were with a Light bilb. I dso not believe there were ever LED illuminated rotary WEs though. Were rotaries always a light bulb?


WE did make rotary Trimlines (223A) with LED dials.
"C'est pas une restauration, c'est une rénovation."--François Martin.

markosjal

Quote from: poplar1 on January 27, 2021, 08:24:02 PM
WE did make rotary Trimlines (223A) with LED dials.

Turns out I actually have one! You can see it mildly illuminated here in daylight. This is a NOS WE Trimline.
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Stormcrash

The other WE models with LEDs are the 220C and 220AL handsets. The AL has the LED in the same position as the old incandescent lamp behind the screw plate. I have manufactured sets with converted maxi to modular plugs that have the AL dial, but don't know if the AL dial was also used in new manufacture sets or if that went right to the 220C with the LED in one of the top corners. I don't know when the 223/2223 model number was introduced but it does seem that all customer sales CS sets are of the (2)223 variety

On the original topic of this thread it seems super strange that ITT imported a Trimline clone for their consumer sales program even though they already made a Trimline clone domestically. I wonder if the unit costs of the Spanish models were lower or if they wanted a way to clearly distinguish consumer vs telco sets on the gray market

Key2871

If one has a western trimline set, rotary and want to see if it's LED, just turn the dial slightly just behind the finger stop it so say LED to tell you it doesn't use the 51Al lamp to illuminate the dial.

But that gondola phone is very cool, I've not seen one before, not even in pictures.
KEN

markosjal

UPDATE

In Place of the Zener and LED in the diagram for the Brown Gondola, Where my Red Gondola had no LED nor Zener there (series with handset hookswitch), I added

AC Input of Bridge rectifier in Parallel with 220 Ohms of resistance. At the 2V that I initially tested across LED (with bridge rectifier and no resistor), this should now pass ~9mA of current through the resistor (does not calculate for loss in rectifier)

DC Output of Bridge Rectifier connects to 2.1V 20ma LED (previously tested with bridge rectifier and LED only at 2V)

Although it dimmed the LED some this helps to ensure that if connected to an ATA or POTS line that can do more than 20ma , some of that current will pass through the resistor. This should allow a line current of up to about 30mA, maybe??

Added shrink tube shroud on LED to prevent light spillage

I might open it again and do some current tests later.
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