# What's wrong with my intercom?



## Easy Gibson (Dec 3, 2010)

4 Unit apartment building.

I came home the other night and the intercom in the lobby was screaming static.

I tried pushing the individual buzzer buttons in the lobby but they had no effect on the noise.

Back inside my place I started poking buttons on my intercom and to my horror found that I was the problem. When I would jiggle my Talk button the noise would lessen. When I held it down, it would stop.
I took the intercom off and removed the wires and the noise stopped completely. That sounds to me like bad solder on the board, right?

I need to pick up a replacement but I want to make sure I get the right kind/actually solve the initial problem.

Here's some pictures. Any thoughts on what I should get or if the unit itself was actually the problem and not the wiring?

Wires









Old ass intercom









Guts


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## Tinstaafl (Jan 6, 2008)

Unlikely the wiring's bad. Likely just ratty switch contacts. Sometimes a good dousing with a can of electronic spray cleaner while working it vigorously will straighten it out for a good while, but replacement is best.


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## Easy Gibson (Dec 3, 2010)

Are the wiring of these things relatively standardized?

Basically, what are the odds of me walking into a big box store and walking out with a viable replacement?


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## Tinstaafl (Jan 6, 2008)

_Relatively_ standardized, yes. But without some basic electronics knowledge, it's very much a crapshoot whether you'd buy the right one--let alone wiring it up properly.

See if a local TV repair place would be willing to service it.


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## rrk (Apr 22, 2012)

Easy Gibson said:


> Are the wiring of these things relatively standardized?
> 
> Basically, what are the odds of me walking into a big box store and walking out with a viable replacement?


less than zero


Has the noise stopped with your unit off with the wires still fed through as in the picture? If so one of the 3 buttons on your unit is stuck, look under the circuit board for a stuck spring or the copper foil loose from the button plate. 

It is also possible one of the wires was grounded , hook the wires up to the unit but don't attach it to the wall. Check for noise; attach it to the wall check again.

To get a replacement you need to find maker then find distributor then open wallet, sometimes very wide. They normally are not interchangeable. Very simple construction, 3 buttons and a speaker nothing else. 9 times out of 10 button is stuck, 10th time grounded wire

I used ti install and service intercoms in multifamily buildings for about 6 years.


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## rrk (Apr 22, 2012)

this one should work
http://www.leedan.com/IR-205E.htm

that is a Lee Dan system correct? I can't read the white tag



boy you are lucky
http://www.amazon.com/LEE-DAN-Apartment-Intercom-Stations/dp/B00L3CZQYO


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## Speedy Petey (Sep 30, 2003)

rrk said:


> boy you are lucky
> http://www.amazon.com/LEE-DAN-Apartment-Intercom-Stations/dp/B00L3CZQYO


VERY Lucky!

If this were any kind of old Nutone system they would tell you you are SOL and have no remorse in the fact that there is no direct replacement known. I've been there.


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## rrk (Apr 22, 2012)

Speedy Petey said:


> VERY Lucky!
> 
> If this were any kind of old Nutone system they would tell you you are SOL and have no remorse in the fact that there is no direct replacement known. I've been there.


I think those Nutones were obsolete the day after they were made. There were always a problem even years ago.


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## C'est Moi (Jun 6, 2015)

rrk said:


> I think those Nutones were obsolete the day after they were made. There were always a problem even years ago.


I don't believe this is a Nutone unit

Here is a replacement for it

http://www.commercialintercoms.com/...uct_Code=IR205E-Tektone&Category_Code=Tektone


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## GettingBy (Aug 19, 2010)

Your replacement has to work with all existing units which are still in place, plus wiring. 
With no schematics to work from, this project has a poor chance of working out and a better chance of making things worse.

With contact cleaner you gamble a few bucks. Do it.

You could also reheat/reflow the solder joints. Do it carefully.

With a helper and an extension cord and knowing the wire gauge and length you could check wiring integrity.

Your pic seems to show only switching, no amplifiers or circuitry. 
With an ohmmeter you can figure out what each switch does and use an external switch to substitute and zero in on the problem.
Which means there is an amplifier somewhere which is much more likely to be the cause.


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## C'est Moi (Jun 6, 2015)

GettingBy said:


> Your replacement has to work with all existing units which are still in place, plus wiring.
> With no schematics to work from, this project has a poor chance of working out and a better chance of making things worse..



The unit I linked to is a replacement unit for that model--IR 205


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## rrk (Apr 22, 2012)

C'est Moi said:


> I don't believe this is a Nutone unit
> 
> Here is a replacement for it
> 
> http://www.commercialintercoms.com/...uct_Code=IR205E-Tektone&Category_Code=Tektone


Its a Lee Dan they have been around forever

Speedy was mentioning that Nutone units are hard to find because they are deemed obsolete

The one I found on Amazon is the replacement


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## rrk (Apr 22, 2012)

GettingBy said:


> Your replacement has to work with all existing units which are still in place, plus wiring.
> With no schematics to work from, this project has a poor chance of working out and a better chance of making things worse.
> 
> With contact cleaner you gamble a few bucks. Do it.
> ...


Nope
With those systems you could have a stuck button for days and it would not damage the amp. Sometimes you could listen through the lobby speaker to hear if someone was talking and try to recognize their voice. It saved time, if not you had to trace it out through the commons.


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## GettingBy (Aug 19, 2010)

rrk said:


> Nope
> With those systems you could have a stuck button for days and it would not damage the amp. Sometimes you could listen through the lobby speaker to hear if someone was talking and try to recognize their voice. It saved time, if not you had to trace it out through the commons.


Agreed. 
Maybe the amp is whacked for other reasons, like:
Age? 
A solder joint with a trapped bubble that has finally caused the connection to fail?

I'm possibly assuming the OP's station is not at fault because 
-if a switch fails you can sometimes feel it so it's a quick & easy test.
-switches are less complex than amps and so can be more reliable.
-it's easy to check them for proper operation with a meter.

Your instincts acquired over years of experience may lead you to different conclusions and you are a better judge of the economics of the repair/replace decision.

My practical experience with intercoms is limited to a summer job at the Fanon-Masco plant in Newark, NJ, testing these suckers. For simple ones you just need a DPDT switch, a step-up audio transformer and an old radio.

I also made one at a NASA facility. On the breadboard it worked fine but when I put it in a box it squealed. Single Point Ground needed!


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## rrk (Apr 22, 2012)

When those amps used to go bad they would do absolutely nothing, no noise no door buzzer (strike)

When he took his unit off the noise stopped , either wire was grounded or button was stuck. When using contact cleaner we had to make sure it was safe for plastic, my boss got a good deal on some that was'nt. Melted all of the plastic buttons so they would not move.


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## GettingBy (Aug 19, 2010)

rrk said:


> contact cleaner


I used to use carbon tetrachloride. This strong-smelling stuff is probably outlawed now. 

Wait a minute! :blink: 

That probably accounts for many of my symptoms! :laughing:


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## limax (Mar 31, 2018)

*tektone pk 205 help needed*

Hi everyone!
I know how works 4 wirw intercom like Lee Dan, Apple Core, etc 4 wire system (1,2,3 (common wires) + x (panel button)) and can answer to any question about it. 
But I have no expirience with 5 wire system (tektone pk 205 - A,B,C,D + panel button wire).
I know that Lee Dan, Apple Core... are compatible with Tektone

Lee Dan wire # Apple Core wire # Tektone wire #
C 1 ???
PT 2 ???
T 3 ???
B X ??? 

Question:
What numbers (1 ,2, 3, X) correspond to Tektone amp letters (A, B, C, D )


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## Inner10 (Mar 12, 2009)

limax said:


> Hi everyone!
> I know how works 4 wirw intercom like Lee Dan, Apple Core, etc 4 wire system (1,2,3 (common wires) + x (panel button)) and can answer to any question about it.
> But I have no expirience with 5 wire system (tektone pk 205 - A,B,C,D + panel button wire).
> I know that Lee Dan, Apple Core... are compatible with Tektone
> ...


This was years ago.

I still service and install them too, ones I stock are Mircom.


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## tjbnwi (Feb 24, 2009)

Can you hear me now?

Tom


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## Leo G (May 12, 2005)

Well, Easy never updated us on this.


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## limax (Mar 31, 2018)

Do you know which letter in Tektone corresponds to which number in Lee Dan?


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## Inner10 (Mar 12, 2009)

limax said:


> Do you know which letter in Tektone corresponds to which number in Lee Dan?


Both used 3/4/5/6 wire stations. But only the 5 and 6 wire used numbers.

If you look at the intercom controller you will see different terminals like PT and T that have (3W) and (4W) lables. They are used for 3 wire and 4 wire versions. The terminals don't directly translate, you can't swap a 3 for a 6 without moving the wires at the head end.

On a 3 wire you have:

C
T (3W)
B

4 Wires are

C
PT (4W)
T
B

5 Wires are

SIG - (To Ent Panel)
1 - Goes to D Terminal
2 - Goes to T Terminal (Like the 3/4 Wire Versions)
3 - Goes to PT
C

6 Wires

D - (Same as 1 on a 5 wire)
- - Goes to AC
PT - (Same as 3 on 5 wire)
C
T - (Same as 2)
SIG

Hope that helps.


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## ComRemodel (Jul 5, 2016)

Unbelievable. Two pages to figure out that it's made by Lee Dan even though it says so in BIG letters on the front. The label inside identifies it as an IR-205. http://www.leedan.com/IR-205E.htm

Get it from Amazon https://www.amazon.com/LEE-DAN-Apartment-Intercom-Stations/dp/B00L3CZQYO

Or better yet why don't you get your building super or owner to fix it???

-Hal


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## Inner10 (Mar 12, 2009)

ComRemodel said:


> Unbelievable. Two pages to figure out that it's made by Lee Dan even though it says so in BIG letters on the front. The label inside identifies it as an IR-205. http://www.leedan.com/IR-205E.htm
> 
> Get it from Amazon https://www.amazon.com/LEE-DAN-Apartment-Intercom-Stations/dp/B00L3CZQYO
> 
> ...


It was 3 years ago...


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## ComRemodel (Jul 5, 2016)

And he's probably still scratching his [STRIKE]a**[/STRIKE] head. 

-Hal


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## Inner10 (Mar 12, 2009)

ComRemodel said:


> And he's probably still scratching his [STRIKE]a**[/STRIKE] head.
> 
> -Hal


No he's out painting houses.


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