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Wednesday
Aug082012

Common problems with NuTone Intercom systems

NuTone started making music intercom systems back in the 1950's, and for the past 55 years homeowners have had a hard time finding someone to service and repair their systems.  As one of my favorite electrical contractors would say "those NuTone systems are finicky"!

Having spent the past 30 years servicing and repairing NuTone Intercom systems, there is very little that I haven't seen (although I do get surprised now and then).  

The way I approach intercom problems is fairly simple. Every model that NuTone has ever made has a list, and on that list are the 10 most common problems with each model.  What the 10 problems are will be different for each model and be different as models age.

For instance, 10 common problems with an IMA4006 when it was new will be different than the 10 common problems when it is 25 years old.

One thing I tell my customers is that when a system has a problem that isn't on the 10 most common list, the problem is usually something simple or something expensive.  This may sound odd, but it is most often true. 

In this section I will be outlining the ten common problems with each model of NuTone Intercom systems.

There will be some history about NuTone intercoms, which helps put things into a context and this makes understanding the problems and solutions easier.

You can also ask questions regarding problems with your system by using the email link on this site.

I have begun adding downloadable NuTone Service manuals on the Service and Repair Manual page.  These are the actual factory manuals which I learned from and each model can be repaired with.

There's no reason to live with a broken intercom system, lets find out what's wrong and fix it.

Chris

 

Thursday
Aug092012

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.