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Princess phone dial lamp power supply

Started by TelePlay, August 25, 2022, 06:39:40 PM

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TelePlay

The WE Princess used a 2012A 6-8 VDC wall power supply rated at 1.75 VA.

Can a 6 VDC supply rated at 1.0 VA be used to light the Princess lamp?

RDPipes

Quote from: TelePlay on August 25, 2022, 06:39:40 PMThe WE Princess used a 2012A 6-8 VDC wall power supply rated at 1.75 VA.

Can a 6 VDC supply rated at 1.0 VA be used to light the Princess lamp?


I have the original Pwr supply if you need it sir and I think a bulb and socket ta boot.

TelePlay

My question was is it okay to light a GE-259 incandescence lamp rated at 1.57 watts with a 6 VDC 1.0 VA adapter?

Seems like the 2012A at 6-8
VDC and 1.75 VA is power overkill for a lamp drawing about 1/4 amp at 6 VDC.

Anyone see a downside to using a 1 VA adapter with a GE-259?

The 2012A has the power to generate 10 watts at 6 VDC.

countryman

#3
Talking about DC, VA is Watt (Volt times Ampere).
So a 1.5 Watt bulb will draw 0.25 A at 6 Volt (6x0.25=1.5)

A 1 VA (or W) power supply is undersized to power a 1.5 W bulb, especially in permanent use. There are plenty modern wall wart type power supplies being capable of much more power.

VA and W in fact may have a different meaning in AC due to the power factor (V and A not happening at the same time).


Edit to add: A 6 Volt 1 Ampere (not VA) power supply should work fine.

TelePlay

Quote from: countryman on August 26, 2022, 02:03:02 AMTalking about DC, VA is Watt (Volt times Ampere).
So a 1.5 Watt bulb will draw 0.25 A at 6 Volt (6x0.25=1.5)

A 1 VA (or W) power supply is undersized to power a 1.5 W bulb, especially in permanent use. There are plenty modern wall wart type power supplies being capable of much more power.

That helped. WE did things great but rarely clear.

The 2012A Class 2 transformer rating is Primary: 105-125 60 CPS; Secondary 6-8 V and 1.75 VA.


I errored in saying ". . . is it okay to light a GE-259 incandescence lamp rated at 1.57 watts with a 6 VDC 1.0 VA adapter?" The adapter specs should have been 6 VDC 1.0 A. Big difference.

Raises another question. Does the 2012A provide 6-8 V as AC or DC? I don't have one at hand to test on my digital multi-meter. Does AC vs DC matter to light a Princess dial lamp?


Wall warts usually provide DC as the secondary voltage. So, if I got this right, a 6 VDC 1.0 A wall wart provides up to 6 watts of power (P=IV) and since the 6 volt GE-259 dial lamp only requires 1.57 watts, this size wall wart should be more than sufficient to power one Princess dial lamp.

And, the 2012A with 1.75 VA or 1.75 watts at 6-8 V would have been just a bit more power than needed to light one Princess dial lamp.


Been too many years since my last class in college physics so thank for any help and verification of my thinking above.

countryman

#5
For an incandescent light bulb AC or DC would not matter. I assume the adapter ONLY powers the bulb and is connected to nothing else inside the phone? Then you could use the new adapter without problem.
Rectifying and smoothing would have been an additional complication in the old days and I assume it was avoided when possible. Chances are, the WE part is AC/AC as nothing else is stated.
It would be fatal to use AC where DC is required, e.g. for electronics of most kind. Vice versa, and when only a bulb is involved, no issues.

eagle

Post pics after you get yours working.  I have a yellow rotary princess phone (with ~25' cord and 4-prong connector still attached), and a friend sent me the power supply.  Last time I had it plugged in, it all worked.

TelePlay

Quote from: eagle on August 26, 2022, 08:05:24 AMPost pics after you get yours working.  I have a yellow rotary princess phone (with ~25' cord and 4-prong connector still attached), and a friend sent me the power supply.  Last time I had it plugged in, it all worked.

Don't know what pictures you wanted so here is the Princess with a GE-259 incandescent lamp powered by the 6 VDC 1.0 A adapter posted above.

This is with the handset on hook so the lamp becomes a faint nightlight

Princess Nightlight.jpg

And this is the handset off hook so the lamp goes to full brightness for dialing

Princess Dial Light.jpg

There is a slide toggle switch on the back base right next to where the line cord enters the phone to turn off, or turn on, the nightlight function. With the switch in the shown position, the nightlight would be on. Move to the left and the night light function stops, the night light goes out.

Princess nightlight shut off-turn on toggle switch.jpg

The toggle switch is a simple SPST switch which takes a low voltage out of the lamp when on hook to turn off the nightlight. I've used a rotary Princess on my night stand for years and that nightlight feature is very nice so I don't know why anyone would turn it off.


MMikeJBenN27

I have a 1960 Princess that doesn't need a power supply.  The light works from just the phone system.  Were any Princess's made this way, or did somebody modify it?

Mike

TelePlay

Quote from: MMikeJBenN27 on August 30, 2022, 11:30:10 PMI have a 1960 Princess that doesn't need a power supply.  The light works from just the phone system.  Were any Princess's made this way, or did somebody modify it?

Here are 3 topics when read should answer your question.

http://www.classicrotaryphones.com/forum/index.php?topic=19581.0

http://www.classicrotaryphones.com/forum/index.php?topic=19568.0

http://www.classicrotaryphones.com/forum/index.php?topic=17984.0

Other than the newest Princess

QuoteThe last AT&T Princess --  the 2703BMG Signature -- had an LED dial which was line powered when the phone was off-hook. However, if a subscriber also wanted the nightlight feature, it was necessary to connect an external transformer!

which only had an off hook dial light, rotary Princess phones used the incandescent lamp lit by the external power transformer.

I moved into a place some 20 years ago that had a 2012A stuck into a basement outlet with two wires running to the phone lines. It was connected to black and yellow internal conductors. As such, every phone jack in the house had 6-8 VAC on the yellow and black conductors, so which ever phone jack was used to connect a Princess, the Princess nightlight and dial light would work. That made it look like the Princess lamp worked off of the line, quite the slick trick by the telephone company.

Problem was, I needed the extra pair for second line (remember those pre-cell phone days when you needed one line (pair) for your computer modem and another line (pair) to talk to people while being on the computer?) so the universal transformer was removed to make yellow and black available for a second line.

Any installers out there ever put a transformed in that way, to light up the whole house?

poplar1

#10
"Any installers out there ever put a transformer in that way, to light up the whole house?"

One 2012 transformer located in the basement of a residence would power 1 Princess or multiple Trimlines. (This  is because of the night light on the PRN.)

One 684A or other anti-sidetone subset could be extended to multiple 404 4- conductor jacks for a single portable 202. (Two 202s could not be connected to one anti-sidetone subset, because both transmitters would be live whenever only one 202 was off-hook.) The 4-prong plug and jack were invented for the 202.

Any number of 102s, 20-ALs, 51-ALs, etc. could be connected to a single sidetone subset such as a 534A. In 1930s apartments here in Atlanta, triple (3-conductor) wire went from the basement to each apt. near the entry, where the 534A subset was mounted on a backboard. The desk stand telephone might be connected directly to the subset. In one apt. I rented, triple wire from the subset output went to a 42A connecting block in the living room, so that a 51-AL or 102 could be installed in the living room.
"C'est pas une restauration, c'est une rénovation."--François Martin.

MMikeJBenN27

You are misunderstanding me.  I am not asking if it can be done.  About 10 or 12 years ago, I bought a 1960 Princess 701B through E-Bay.  The light feature works without plugging a power cord into an outlet.  I have not modified it, nor does it have an LED in it.  I was asking if Ma Bell made any Princess phones this way, or did a previous owner/subscriber modify it?

Mike

Stormcrash

Quote from: MMikeJBenN27 on August 31, 2022, 05:35:25 PMYou are misunderstanding me.  I am not asking if it can be done.  About 10 or 12 years ago, I bought a 1960 Princess 701B through E-Bay.  The light feature works without plugging a power cord into an outlet.  I have not modified it, nor does it have an LED in it.  I was asking if Ma Bell made any Princess phones this way, or did a previous owner/subscriber modify it?

Mike

As far as I'm aware they didn't and I'm actually confused/curious how that even works. Every indication I've read is that the line current wouldn't be enough to light the lamp or that the resistance would appear as on hook depending on if the incandescent lamp was in series or parallel to the phone electronics.

The only princess I know of that didn't require a transformer for the dial light was the Signature Princess in the 90s that used an LED backlight, and on that set the LED would only work when off hook unless a transformer was used (at least I think it supports a transformer for night light mode)

poplar1

Did another PRN connected ro the same block also light up?

Is it possible that there was a 2012 transformer in another room, (or in the basement like Teleplay's house), and the installer connected all 4 conductors to all the outlets?
"C'est pas une restauration, c'est une rénovation."--François Martin.

TelePlay

Quote from: MMikeJBenN27 on August 31, 2022, 05:35:25 PMThe light feature works without plugging a power cord into an outlet.

No, fully understood what you remember having. The topic I linked discussed the lamp from every perspective including that 90s LED version which only lit when off hook.

Did you have a 2012A plugged into a basement outlet near the incoming phone line that was connected to the outer pair, yellow and black? Do remembering checking or testing the outer pair at the wall to see if they were carrying 6-8 volts?

Also my question is when did the light you are referring to come on, when on hook, off hook or both?

If on hook, how does a 6V lamp survive 90V ring voltage?

If off hook, did the lamp flicker when pulse dialing?

Early Princess line cords were 5 conductor, red and green for L1 and L2, yellow for grounded ringing and black and white for the separate 6-8 Volt lamp power supply.

Today, with bridged ringing, only 4 conductors are needed in the line cord with the outer pair (yellow and black) being used to power the lamp circuit which is totally separate from the talk/ring circuit.

I also can't see how the lamp in your early Princess was powered.