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A Brief History of NuTone Intercom Systems

Part 1

In order to understand NuTone intercom system designs you need to understand how the systems fit onto a time line. NuTone system designs were evolutionary, meaning that new models were based on the previous models, but with new features and better technology.

NuTone would design a “platform”, which was the fundamental building block that every model would use. By adding features to the platform, new and different models would be created.

NuTone intercom systems can be divided into different groups based on the type of wire each platform uses. There are two main wire types: 3-wire systems and 6-wire systems. These two wire types comprise about 80% of all NuTone intercom systems.

There are a few exceptions with regard to wire types. NuTone has also made 5-wire, 8-wire and 4-wire systems.

Another design consideration with NuTone intercoms systems is how the wiring is laid out and installed. There are two types of wiring schemes that are used with NuTone intercom systems. They are Home-Run systems and Loop-Wired systems.

Home-Run Systems: In a home-run wiring layout each remote station (entry door, inside and patio) has its own individual cable with the appropriate numbers of wires in the cable (3,4, 5, 6 or 8 wires) and these cables all run directly back to the master station. As an example, if there are 9 remote stations, there will be 9 cables behind the master station. Home-run systems comprise 80% of all NuTone systems.

Loop-Wire Systems: In a looped-wired system, there will be multiple stations on a single cable of wires. As an example, if there are 9 remote stations, these may be grouped onto 3 cables. Cable #1 may have 3 stations, cable #2 may have 4 stations and Cable #3 may have just 2 stations. Behind the master station you will only find the 3 cables. NuTone loop-wired systems use either 6 or 8 wire cable.

One thing to keep in mind is the following rule: NuTone intercom models that were designed to be Looped-Wired systems can be looped-wired or home-run, either layout or a combination of both will work. NuTone intercom models that were designed to be Home-Run systems can only be installed with Home-run wiring, no exceptions.

All of the original NuTone intercom systems were vacuum tube designs, and all vacuum tube models are 3-wire systems with one exception (model 2400, which is a 5-wire, home-run Stereo Music Intercom System).

The first model to use solid-state electronics (transistors and diodes) also used a different wire type. It was the model N2561-2562. This revolutionary model was a huge design step forward for NuTone and was an 8-wire, loop-wired system. The N2561-2562 was in production from 1957 through 1974, that's 17 years!

A quick note about early NuTone model numbers: In the early days, NuTone used model numbers like 2011-2012. The 2011 and 2012 are basically the model except the finish (color) of the model was different. For example, the 2011 had a silver faceplate and the 2012 had a copper-tone faceplate. This is the way NuTone labeled their Intercom models until the mid 1970's. After 1974, NuTone added letters to the model number to denote the finish of the intercom. For example a IMA303T (traditional) was a dark walnut finish, and an IMA303L (light) had a light maple finish.

The last year of production for vacuum tube models was 1966. Since then all models have solid-state electronics.

Vacuum Tube 3-Wire Models:

1954 – 1966: 2011/2012 2013/2014 2015/2016 2053/2054 2055/2056 2057/2058


Vacuum Tube 5-Wire Model:

1957 - 1962: 2400 Stereo Music Intercom


Solid-State 3-Wire Models:

1966 – 1971: 2067/2068

1968 – 1975: 2090/2091 2063/2064

1975 – 1983: IM203/IMA203 IM303/IMA303 IM323/IMA323 IM313/IMA313 + B,C,D

1984 – 1994: IM2003 IM3003/IMA3303 IM3103/IMA3103

1994 – 2006: IM3303/IMA3303


Solid-State 5-Wire Model:

1966 – 1972: 2071 Stereo Music Intercom


Solid-State 8-Wire Model:

1957 – 1974: N2561/N2562 2500

1975 – 1983: I600 SM428


Solid-State 6-Wire Models:

1965 – 1975: 470

1968 – 1975: 2540/2541 2542 462

1975 – 1985: IM406/IMA406 IM806/IMA806

1986 – 1995: IM4006/IMA4006 IM5006

1996 – 2006: IM4404/IMA4406 IM5000


Solid-State 4-Wire Models:

1997 – 2004: IM3204/IMA3204 SR9000 Stereo Music System


Finally we have to include the rarest NuTone Intercom model ever made, the IM6106. Originally the IM6106 was scheduled to be released in 1988 but due to design and manufacturing problems, the release was delayed many times. There were about 400 pre-production units released to dealers and installed in homes. For the next 3 years, everyone struggled to keep these units working until finally the model was dropped and all of the 400 units were replaced at NuTone's expense. If you have an IM6106 you have a rare and unrepairable unit.


Reader Comments (105)

I could not find the e-mail link on your website. I have an IM-860M intercom system which was purchased new during the 1980's but never installed. I know someone who has a model 3003 which no longer works. There are burnt areas on one of the circuit boards. I would like to replace their system with my 806. Is that feasible?

September 13, 2012 | Unregistered CommenterTom

Unfortunately an IMA806 will not be the correct replacement for an IM3003, because the IMA806 is a 6-wire system and the IM3003 is a 3-wire system. The IM3003 is probably repairable and you can contact u s by email for information about having it repaired.

October 29, 2012 | Unregistered CommenterChristopher

Hello there. We have lived in our house for over 12 years now, and when we moved in there was a radio/intercom system, which is a NuTone IMA-203 FM-AM. We are in the process of remodeling our kitchen, and we would like to replace the radio chassis so it will not look so outdated. The system works okay.. I was reading your article and we are having some of those problems, but we only use the radio, not the intercom. We can take the steps to clean off the controls inside it, and it will most likely work perfectly. Anyway, is there any way to just replace the radio in our kitchen and not have to replace the whole system? All the newer systems seem to be so much smaller than ours, and the hole in our wall is pretty big (about 16 x 9), so not sure if this will work. What do you suggest?

Thank you,

Joni L.

March 13, 2013 | Unregistered CommenterJoni

Hi Joni,

Unfortunately you will not be able to replace just your IMA203 Master Station and reuse the remote stations. This is because of the age of your system and that it uses a different design platform than the new NM100 series. It will be necessary to replace not only the IMA203 but all of the remote station as well. All of the new NM series equipment is smaller than your equipment tha is installed in your home, however NuTone does offer a wide variety of update frames that will cover the existing opening behind each station.

If you would like to contact me directly, I will be happy to help you put together a proper list of the new equipment you will need to update your IMA203 system.


March 14, 2013 | Registered CommenterCindy & Christopher

I got a call from a colleague who has a 3303 system, already upgraded once from a 3003 (?). He's complaining his door chime (unknown model) doesn't work, and "the repair guy" said a) he needs a new one, but b) they're not available, but c) he can get something for $180 which "might" fix the problem. I ran the computer department before retiring, so that makes me the expert on all things electronic. I'm going over there tomorrow to have a look, and your site has been of great help in getting me going. That's all I know now. Any tips would be appreciated; for now I'm just going to do some basic debugging, wire tracing, checking for obvious damage, proper power, etc. I may be in touch to see if I should just put all the pieces in a box and send them off to you.

June 21, 2013 | Unregistered CommenterMike Armstrong

Hi Mike

There's not enough specific information for me to give you any solid ideas or answers as to what or where the problem is, however if the original Chime Module was reused from the original IM3003 in the new IM3303, it would not be uncommon for it to fail after having been transfered. I have seen this happen many times.

June 22, 2013 | Registered CommenterCindy & Christopher

Problem solved without even going inside. I don't know what "the repair guy" had for qualifications, but I'm a believer in KISS. Took the cover plate off the unit by the front door, and shorted out the terminals on the pushbutton. Bing, bong, etc. Replaced the pushbutton with a generic lighted button switch from Home Depot (gen-u-ine Nutone buttons are available for $7 online) and he was good to go. Old switch was apparently corroded after 20 years in the Florida outdoors, which isn't a bad record. Owner was so happy to have saved $178 that he let me hook up his new DVD/VHS recorder to his giant LED TV.

June 23, 2013 | Unregistered CommenterMike Armstrong

Hello we have a 3303 system installed in our house and it worked like a champ until an electrician did some work for which he had to turn a bunch of breakers on and off at the main switch. Since then the Nutone master station is stuck on the one FM station it was on previosly and it ignores all buttons, swiches etc. Cannot change stations, cannot turn it off nothing. Luckily, I was able to turn the volume down all the way so it is at least quiet. Any ideas where to start? Any help would be appreciated. The wife is on my case to fix it ASAP. Help!

June 26, 2013 | Unregistered CommenterIB

Hi, Your IM3303 needs to be reset. Open the right hand door on the bottom edge of the master station, the last button on the right is the "memory set" button. Just past the button is a hole in the panel, inside the hole is the main reset button. Use a smaller screwdriver or toothpick and push the reset button, hold it for 5 seconds. This should correct the problem. If not please call me to discuss further troubleshooting.


June 26, 2013 | Registered CommenterCindy & Christopher

Thanks for the prompt response. I tried the reset procedure and the results are below:
1) Before reset: LCD Display blinking & FM Red LED solid ON
2) During reset (button in depessed state): LCD display blank & FM Red LED OFF
3) After reset (button released): LCD display back to blink & Red LED solid ON

In other words, the reset procedure didn't seem to make any difference (unfortunately). What should I do next?

June 28, 2013 | Unregistered CommenterIB

Hi IB,

Please fill out an Intercom repair Request Form (last link in the Navigation section) and once I have received it, I will contact you regarding the problems with your IM3303


July 1, 2013 | Registered CommenterCindy & Christopher


I have a Nutone Model 2055/2056. The tubes are good. When I turn it on there is a loud hum. The hum is equal no matter if you turn it to AM, FM or the turn table. Eventually it gets low enough you can hear the FM/AM; however, it never entirely disappears. I went to an electonics store and he suggested replacing the "can" of three capacitors might fix it. I don't mind taking a shot at replacing some of the capacitors, but wondered based on your experience which is the most likely failing part? Thanks. My email is Dave

July 29, 2013 | Unregistered CommenterDavid S.

Hi David,

The hum you are hearing is likely caused by failing 50 year old capacitors. It would be best to replace all of the capacitors in the 2055/56 while you have it apart. The 3-section can capacitor will be a challenge because it is no longer available and finding a match for it (size and values) is unlikely.

When I have these early models in for repair, I "restuff" the can capacitors with modern capacitors to preserve the original look of the unit.

I will also caution you that tube based models have HIGH VOLTAGE and HIGHER VOLTAGE in them to drive the tubes. Extreme caution needs to be taken when working on tube equipment, other wise you can be hurt or if the repair is done incorrectly, it can become a fire hazard.


July 29, 2013 | Registered CommenterCindy & Christopher

Thanks Chris,

I would be willing to try it. However, if you still do these repairs, could send me a price to do that work? If not, how do you take the can apart without destroying it? Why did they put them in a can anyway? Was it because of the higher voltage?


David S.

July 30, 2013 | Unregistered CommenterDavid S

Hi David

Multi-section capacitors were used mostly because they were faster to install during manufacturing. These type of components date back to the early days of radio in the 1930's. I do rebuilt the older tube based models that NuTone made, in fact I have a model 2057 / 2058 Master Station in the shop right now for a rebuild. Please fill out an Intercom Repair Request Form (under the Navigation Heading) and once I have received it, I will contact you about the information you provided.

July 30, 2013 | Registered CommenterCindy & Christopher

I have a 3003 system in a home built in 1986. It has power (I can see the clock and radio station on the digital readout) and when I push the talk buttons I can here static/popping on the local unit
(same goes for pushing buttons on the remote units, just static momentarily when the the button is pushed). The doorbell doesn't work and you can't hear anyone talking between units. None of them.
I opened the main unit and sprayed with compressed air and vacuumed debris (it was full of drywall dust and spiderwebs). I momentarily heard a radio station on the remote units but then it stopped and I couldn't get it back.
What would be the first thing you would try in this situation? Cleaning volume nobs? Thanks for a great site btw!

October 3, 2013 | Unregistered Commentermbeacom

Hi M,

Yes, I would clean all of the volume controls and push button switches first to see if you can get the radio to play throughout the home. You can buy some Deoxit Cleaner from Radio Shack.


October 3, 2013 | Registered CommenterCindy & Christopher


My son just bought a 1972 home yesterday with a model 203 Music Sound, serial # k838155a, in the wall and seven wall intercoms. Is this a New Tone unit? Nothing works as the main unit was no longer wired up to anything, including to the 120v source. The home run wiring is in tact with 4 pair wires. The main intercom/radio also appears in tact. I would like to get it working again. Your suggestions. I am willing to send the main unit to you and have it gone through. It is very dusty and if you can get it working I would like a new cover. Ron

November 17, 2013 | Unregistered CommenterRon

Hi Ron,

From your description I think you have a Music & Sound brand Model 203. If you contact me diorectly I can refer you to someone I know that rebuilds M&S equipment.


November 17, 2013 | Registered CommenterCindy & Christopher

Thank you for your clarity. It helps a lot.
I get freq calls on intercom repairs in los angeles
Do you also repair tektone amps

November 18, 2013 | Unregistered Commenterjack podolski

Hi Jack,

Thanks for the comment. I don't work on Tektone equipment equipment.

November 18, 2013 | Registered CommenterCindy & Christopher

Hello, I have the model 2057-2058 and it seems to work just fine. I turn it on and theres power, lights come on but the intercom doesn't work and neither does the radio. I was maybe thinking the tubes are whats wrong with it?

December 23, 2013 | Unregistered CommenterRobert M

Hi Robert,

While there may be some tubes that need to be replaced, it's likely that there are other things wrong as well. Your 2057 is around 50 years old and time takes its toll on all sorts of parts and assemblies. The last 2057 I rebuilt (just a few weeks ago) needed 8 replacement tubes, new capacitors (including restuffing the multi-section can) and lots of solder re-flowing to bring it back to life. After a little tuner adjustment it played very nicely and work correctly. Please note that tube based models have HIGH-VOLTAGE in their chassis's, which CAN HURT YOU A LOT if you don't know what your doing!!!!!!!!!!

If your interested in have your 2057 / 2058 rebuilt, please fill out an Intercom Repair Request Form and I'll contact you about your Master Station


December 24, 2013 | Registered CommenterCindy & Christopher

Hi Cindy & Christopher,
My house has a Nutone 3103 installed. The system has 4 indoor units, 1 outdoor unit, 2 door units, and the master unit. The intercom feature can be used between the bedrooms and main unit, with lots of terrible cracking noise when switches are pushed, but then the voice is loud and clear. I will have to clean those switches as I read. I can answer the front door (I replaced this unit with an original ISB-64 I bought online, I have not been able to find a second unit to replace the one in the back door that doesn't work. I replaced the unit, however the push bottom does not make the doorbell to go off at the master unit or speakers. I have a regular doorbell, so I know when someone is at the door. Sometimes at any time but I think when it gets cold, or in the middle of the night something triggers the chime to go off continuously, and I can hear the chime in all the units. There is no way to stop it, I usually go to the master unit and turn the volume down and turn all the speakers off. Sometimes the chime stops by itself.
Another issue is that the radio does not have enough volume, I can barely hear the radio if I put my ear next to the speaker, even in a loud volume setting. The patio unit does not work, even the knob or switches won't move, too much humidity in Texas (or I think they installed an indoor unit in an outdoor location. The answering machine does not work. I'm not interested in having it working since I recently cancelled my landline.
What are my options? Is this repairable or should I replace the system?

Thanks in advance for your time.


January 8, 2014 | Unregistered CommenterPerry

Hi Perry,

Your IM3103 is a variation of the basic Model IM3003. The difference is the addition of the Cassette Tape Answering Machine which also doubles as a cassette player throughout the system.

Your IM3103 has the same basic problems that a IM3003 will have, dirty volume controls and push buttons in the remote stations, which all can be cleaned as outlined on this site.

The ISB64 Surfaced Mounted Entry Door Speaker on your back entry probably has a failed speaker cone which is still available and is easy to replace. You can contact us for a replacement cone if needed.

I am unclear about the problem with the door chime, I am not sure if you have a built-in Chime Module installed in the IM3103 or if you have a separate wall mounted NuTone Electronic Musical Chime that rings in it's location and is connected to ring through the IM3103.

If you have the separate wall mounted electronic chime (which I think you do, perhaps a LB55) the problem with the chime not ringing when someone pushes the button and then at other times it rings continuously and won't stop could be a damaged wire or an aged related problem with the chime itself.

If you have a Chime Module installed in the IM3103, all of the problems are likely to be Chime module related.

Non working Patio Stations have usually just weather away and they can be rebuilt (new speaker cone and switch board) or just replaced with a good used station.

The Answering Machine in a IM3103 was a very tricky design and for the most part is very outdated and not compatible with many modern phone systems. For some homeowners have the ability to play cassette tapes makes the unit useful, although adding a MP3 player input jack makes more sense than trying to repair the answering machine section of a IM3103 just to play tapes.

Finally, the lack of overall system volume is caused by a failed Power Supply - Amplifier in the IM3103, this is the same type of problem that all IM3003 will have. This is a common and easily repaired problem.

The choice to repair or replace is always the customers choice and I get asked this a lot. Based on the number of Intercoms we repair every year, and all of the owners I speak with, repairing the Master Seems to be most peoples choice.

If you are interested in have your IM3103 repaired, please fill out an Intercom Repair Request Form (under the Navigation Heading) and once I receive it, I'll contact you directly about the repair of your master


January 9, 2014 | Registered CommenterCindy & Christopher

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