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NuTone Music Intercom Chime Modules

Chime modules were designed to replace NuTone mechanical door chimes and had the added feature of being able to connect to a NuTone Music Intercom system. Connecting a door chime to an intercom system was not a new idea, it was an option that existed since the late 1950's.

In the early days, NuTone made special door chimes that had different types of electronic pickups “like those on an electric guitar” that would sense the vibrations of the mechanical tone bars inside the chime and send those signals to the intercom master station.

The master station would amplify the signals and it could be heard throughout the intercom system.

This was a more advanced type of installation and typically it is seen on more expensive installations. The fundamental problem with this early design was, if the intercom system was turned off, you wouldn't hear the chime throughout the intercom system, only at the chime location. In a bigger home this could be a problem.

NuTone introduced the very first chime module in 1982. It was the model IA22 and it was specifically designed to be used with the infamous IM806. The IA22 was a complex and temperamental design which proved to be a source of many problems. It was replaced with the IAA22 in October of 1984. The IAA22 was a simplified design that worked well.

Later in 1984 the second generation of chime modules were introduced. These new chime modules were models IA27, IA28 and IA29. These three modules were designed to be used in the all new IM3003 music intercom. They can also be used with all NuTone music intercom systems manufactured through the end of 2007.

The IA27 was a short -ived model, having the ability of only a single entry door pushbutton connection and a 2-note chime tone, so its appeal was limited. The IA28, with its 3 entry door option, and a choice of 1-2 or 8 note chime tones, made it the most popular module. The IA29 was NuTone's Musical chime module, having an additional 12 musical chime choices over the standard 1-2-8 notes of the IA28.

NuTone continually improved the chime module designs during the 23 years that they were in production. While these improvements solved the common problems with each earlier design, it also has created a difficult situation when trying to identify which version a customer has. NuTone did not publish service information for every version and schematics are not available for many of the revisions.

The most common problems with chime modules are their complete failure, low volume and self-triggering, which causes the module to ring over and over without stopping.




In the earliest days of NuTone chime modules, failures were somewhat common. In parts of the country that experience electrical storms or lightning, these failures were quite common. It seems that the electrical energy from the storm would travel down the pushbutton wire and hit the chime module, causing it to fail. There were several different attempts by NuTone to solve this problem and by adding MOV's in the chime module's circuitry to “soak up” the energy, this problem became less common.



To understand the problem of a chime module that rings over and over you must understand how the chime module works. You also have to do a little investigating to eliminate other problems that may cause the module to trigger.

The entry door chime feature of a NuTone Music Intercom system consists of three different parts. There is the Chime Module, the Pushbutton at the entry door, and the wiring that connects the pushbutton to the chime module. Any of these three parts can be the cause of the module to ring over and over without stopping.

Before jumping to the conclusion that the module has failed, you must eliminate the other possibility.

First, remove the pushbutton at the entry door and disconnect the wires from the terminals on the button (don't let the bare ends of the wire touch). Did the chime module stop ringing? If so the pushbutton is bad and should be replaced.

If removing the pushbutton did not solve the problem, the second step involves opening up your master station and locating the chime module. Since there are many different models of Master Stations, you will need to download a copy of your models Installation Instructions. These instructions will aid you in finding where the chime module is mounted inside you master station.


Once you have located the chime module in your master station, you will need to identify the screw terminals on the chime module where the wiring from the entry door pushbutton is attached. Typically there are four screw terminals in a row down the center of the chime module.

The four terminals should be marked as “Common” ,“Front”, “Rear”, and “Side”. The Common terminal is usually larger in size than the other three. Most installations will only have 2two wires attached to the chime module at the “Common” and “Front” terminal screws.

Now that you have located the chime module and the screw terminals on the module, disconnect the wires from the “Common” terminal. Did the chime stop ringing? If it did, we now know that the problem is likely the wire that connects the pushbutton to the chime module.

If the chime module keeps ringing after the wire is disconnected, you likely have a failed chime module.




If you have eliminated all of the other possibilities, and you are fairly certain that your chime module has failed, you will need to disconnect the chime module from your Master Station.


On one edge of the chime module board there is a small (1/2” wide), flat (like a ribbon), gray colored cable which is about 6” long. Sometimes the end of the cable that is attached to the chime module board will have a plug end on it, but not always. The other end of the 6” cable always has a plug end on it.

This cable is what connects the chime module to your master station. It supplies the chime module with power to operate and allows the signal from the module to be sent into the master station. To disable the chime module, unplug the gray cable from wherever it is plugged into the master station (refer to your models instructions).

Now that the chime module is disconnected and the ringing has finally stopped, we can look at why the chime module has failed in a self-triggering mode.



Everyone is familiar with how a wall mounted light switch works; you flip the lever and inside the switch a mechanical part moves and it makes a connection and the table lamp turns on. This NOT how a chime module works.

Even though there is a pushbutton at your entry door, it is not exactly like the switch that turns on your table lamp. Part of the chime modules circuitry provides electricity to the wires that connect to the pushbutton. This allows the button to have a little light bulb inside so it can be seen at night.

Part of the chime module's circuit monitors the voltage to the pushbutton. When someone presses the button, the voltage falls and the chime module senses the change in voltage. This change triggers the chime module to ring. If the circuit which monitors the voltage, or the circuit that triggers the module, become too sensitive or too far out of alignment, the chime module will false trigger, over and over.

There is a NuTone Factory Modification for some versions of chime modules to correct false triggering due to the age of the components in the module. If your module is newer (1997-2006) it probably already has this modification incorporated into it and the problem is a failed component. Fortunately, chime modules are straightforward to repair.



I have covered the general reason why the chime module volume may be low in another part of this site. It is usually caused by the system being out of adjustment.

There are also reasons why chime modules can produce low volume that are caused by a defective module. Chime modules are a “High Gain” (lots of signal) device that include a “volume” adjustment on the chime board itself. This adjustment allows the original installer to set the chime level so it's correct for that specific installation.

If this adjustment is not made during the original installation, the chime volume may always have been either too loud or too soft. It is also possible that the chime module has experienced a failure and it is unable to produce the correct amount of signal.

Another problem which we see relates to the chime module's signal, but it is a problem with the Master Station that the module is plugged into. All NuTone music intercom which have the option of a chime module have as part of their circuitry a “Chime Input” circuit. This is where the signal from the chime module enters the master station.

This “chime input” circuit can become damage,d and even though the signal from the module is correct, the input does not process it correctly and the result is very low chime volume.

Neither of these problems is something the average homeowner can repair. In these cases the module or the master (or both) will need to be repaired by a qualified NuTone Service Center.



When it's time to reconnect the chime module to your master station, it is very important to do it correctly, otherwise you will damage and ruin your new or newly repaired chime module. I covered how to unplug the gray cable that comes from the module and is plugged into the master station.

If you look at the gray cable carefully, you will notice that along one side of the ribbon cable there is a red stripe. This red stripe is the index marking for pin #1 on the plug end. The plug end is also made so it can only be plugged into the socket one way (even though if you push hard enough you can get it wrong)

If you plug the cable in backwards, you will destroy the module. If you are unsure on how to plug the module in correctly, download a copy of the IA28-IA29 chime module instructions and follow them....



If your chime module is ringing over and over, don't just ignore the problem and turn down all of the volume controls so you won't hear the chime tones. The constant signal input from a chime module will damage your Master Station if the problem is not corrected. Turning down the volume controls does not reduce the signal from the chime module into the master station. If it is left this way for a long period of time (months) it will cause the amplifier in the Master Station to become damaged, which will cost more to repair.

See all of the NuTone Chime Module Pictures



Why is my Chime Module Volume So Very LOUD?

Whenever we return a customer's repaired NuTone Intercom Master Station, we include simple to follow instructions on how to set up the adjustments for their particular model of Intercom System.

The basic purpose of these Set-Up Instructions is to make sure that the newly repaired Master Station will work as it was originally intended.  The most common error with NuTone Intercom System adjustments is that the volume settings are set much too low, which effects how well the intercom portion of the system operates. Over time this adds extra stress to the amplifier.

One of the by-products of setting up any system correctly is that, suddenly, the volume of the built-in Chime Module is very loud...much louder than it was before the repair.

Volume Settings on NuTone Chime Modules

The two most common models of NuTone Chime Modules are the IA28 and IA29.  These were in production from 1984 through 2008.

These Chime Modules are used in every model of NuTone Radio Intercom System made during that time. 

Chime Module were always an "Optional Extra", which meant that you had to pay extra to have a Chime Module added to your Intercom System when it was being installed.

When the installer put the Chime Module into your Master Station, the volume adjustment was not "Pre-set" from the factory. The installer was responsible for making the volume adjustment during the installation. Often, or at least most of the time, this did not happen.  In many, many installations, the Chime Module Volume is set way too loud for most home owner's needs.

Once the homeowner hears how loud the chime is, they do what would seem natural, and they turn down the volume on every Intercom Station.  While this does lower the chime volume, it also effects the overall operation of the Radio and Intercom features of the system.

Basic Steps for Correcting the Volume of a Loud Chime Module

1.  Turn all of the Volume Controls on all of the Remote Stations to Maximum (fully clockwise)

2.  Turn the Volume on the Master Station to Maximum

3.  Locate the "System Volume" or "Program Volume" on your Master Station

4.  Turn on the Radio (AM or FM) and tune it to a strong station

5.  Adjust the "System Volume" or "Program Volume" to achieve a comfortable Radio Volume throughout the home

Now, ring the door bell by pushing the door bell button on your front porch.  If the Chime is now very loud (louder than you would like it to be) Watch the Video and see how to adjust the Chime Module's Volume Setting.


I used a NuTone IM3303 Master Station in the Video as an example.  The basic steps of making the Volume Adjustment are the same for most NuTone Radio Intercom Systems.

What is different from system to system is where the Chime Module is mounted inside the Master Station.

On our You Tube Channel, you will find Play Lists for many different NuTone Intercom Systems.  Most of these Play Lists include a Video which shows how to completely remove the Master Station.  Part of each of these "Removal Videos"  will show where the Chime Module is mounted inside that particular Model.

Use This Button for our You Tube Channel Play Lists