Old home intercom.

[recyclebinned]

I have a home intercom in a two story condo from 1963. The intercom has three built in wall units that were=20 installed at the time of construction. One unit is outside next to the front door and there is a unit=20 on each floor. There are eight apartments and they all have the same type of intercom. Below the first floor is a parking area and above the second floor is a=20 flat roof. The power source for the intercom is not=20 behind any of the units and don=92t seem to be in the=20 parking area or on the roof. I checked some of the=20 closets but I didn=92t go through them inch by inch.=20 The units seem to have some power coming in so I=20 assume that the power source is still somewhere and=20 operational. I would like to locate the power source=20 without having to buy a three thousand dollar cable tracker and would appreciate any input as far as=20 what the usual location might be when installing=20 a power source for intercoms of this type for similar layouts?=20 Thank you.=20

[John Grabowski]

I have a home intercom in a two story condo from 1963. The intercom has three built in wall units that were installed at the time of construction. One unit is outside next to the front door and there is a unit on each floor. There are eight apartments and they all have the same type of intercom. Below the first floor is a parking area and above the second floor is a flat roof. The power source for the intercom is not behind any of the units and don?t seem to be in the parking area or on the roof. I checked some of the closets but I didn?t go through them inch by inch. The units seem to have some power coming in so I assume that the power source is still somewhere and operational. I would like to locate the power source without having to buy a three thousand dollar cable tracker and would appreciate any input as far as what the usual location might be when installing a power source for intercoms of this type for similar layouts?

*If it is a remote transformer it is supposed to be accessible. Usually the easiest place for installation is on or near the electrical panel, but in a condo it could be almost anywhere. I suggest flipping each circuit breaker off one at a time to see which one shuts down the intercom power. If it is connected to an outlet or lighting circuit, that may help narrowing the location down. Did you open up the electrical panel to see if anything was inside or seem to be attached to the exterior of the panel, but in the wall? Is there an attic space that you get up into and look around?

[bob haller]

first try the obvious ask each unit owner if they have located the power source...

my home had a missing doorbell, transformer in basement, wirest to front door, and wires going somewhere but i didnt have a clue where the bell originally was.

asked a friendly neighbor, tract home, all similiar. found the wires within 5 minutes and have had a doorbell ever since with near zero work.....

if you can detect power at the units try tripping breakers till you find which breaker the units are on...

is your purpose to discnnect them permanetely? replace them? or try to repair them?

[Percival P. Cassidy]

Does that mean that the doorbell transformer that I discovered next to a now-unused ceramic light socket above a suspended ceiling is in violation of the Code?

Perce

[trader4]

If the suspended ceiling panels are removable, then anything there is accessible. It doesn't have to be out in the open, just accessible.

[recyclebinned]

I didn=92t try turning off the breakers to narrow down the location because= it is a very small condo but it=92s better than nothing, I will try that. = I didn=92t think of opening the service electrical panel because I didn=92t= think they would put low voltage in with high voltage but now that I think= about it who know what they would have done in 1963. I will also try that.= There is no attic at all. Thank you for the suggestions.

[recyclebinned]

The owners of the apartments are some of the most clueless people I know so= I didn=92t try that but I will ask them anyway. I like to repair them and = I know a place that should have all the parts that I need.

[recyclebinned]

No suspended ceiling, just sheetrock.

[Oren]

didn?t try that but I will ask them anyway. I like to repair them and I know a place that should have all the parts that I need.

Does this building have a common mechanical room for all the units? Might be something there, if so. Just guessin'.

[NotMe]

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The intercom should have a make/model number somewhere (typically on the outside) with more info on a name plate inside.

That would be a big help.

That said most of those of the 60's vintage ran on a 24 VAC transformer not unlike the door bell transformers (and may well be shared by the bell)

I would mention that the electolited filter capacitors are very likely bad and you may have a heck of a hum in the audio as a result.

[trader4]

Interesting angle. And even if the transformer is not shared, I would think there is a good chance it could be located by the doorbell one. When wiring these things doing the intercom and doorbell at the same time since they end in the same place seems logical and they could be in the same place.

[fred.flintstone]

If you removed one of them, there MUST be some sort of power wire entering the back of it.

Since you did not say what you intend to do, I can not assist more....

However it you just want them disconnected, simply cut the wires off each intercom and wirenut them. You dont have to wirenut speaker wires, just those that have power. If you want to fix them, take each one to a tv-radio repair shop. I dont doubt that most of them still work, so try them first. From 1963, these may still be tube type?????

[clare]

Stupid, yes, but not counter to code as a suspended ceiling (T-bar" type) qualifies as "accessible". Unless the area above the ceiling is used as an air return "plenum", in which case it violates a different code section.

[clare]

Up here in Ontario, many Nutone systems were installed that DID share the doorbell transformer - and many of the intercoms WERE the doorbell if I remember correctly. My late father installed quite a few in his job as a residential electrician.

[recyclebinned]

Maybe it did share the same transformer at one time but it doesn=92t anymor= e because even if I turn-off the power supplying the doorbell I=92m still g= etting a 10.5 VDC from the intercom circuit while the doorbell transformer = is reading a little over 12 VAC. This leads me to believe that whether 10.5= VDC is the correct voltage or not it sure isn=92t AC and not on the same c= ircuit as the doorbell, but thank you for your input.