Updated NuTone IM5006 Master Station Rebuild

It's been two years since my original post about rebuilding a NuTone IM5006 Master Station, and it's time for some updated information.

Something I keep in mind all of the time is that all models of NuTone Intercoms are always getting older, and with age comes new or expanded problems. Many of the IM5006's we receive in are on their 2^nd or 3^rd repair since they were originally installed.

Why is this? It's due to several factors. When the IM5006 was new, it was covered by NuTone's MPP Lifetime Warranty. During the MPP period, it was very common to send a customer's complete Master Station back to the NuTone Factory Repair Shop in Cincinnati for repair. The problem with this turns out to be the way the in-warranty repairs were done. It seems that the work done on these MPP Warranty Masters would be the absolute bare minimum required to get the IM5006 working again. I have seen sets with a few as 2 components replaced by NuTone.

The problem with this style of repair is that it leaves dozens of similar components in the same circuits that will soon fail. Each time some of these components fail, the IM5006 will need to be repaired again.

After NuTone closed its Factory Repair Center, an independent Repair Center was opened by a former employee of NuTone. Unfortunately, this shop continued the same level of work that was done at the NuTone Factory (they have since gone out of business).

From what I have observed, the independent shop did not follow good practices with the repairs they performed. Along with the lack of thoroughness with the repairs, they often installed improper component values, which I believe was a misguided attempt to “better” the design (this rarely works). They also used low-quality parts.

Yesterday I had one of these units on the bench for repair (the 3^rd repair). Without going into all of the details of what I found, let's just say it wasn't done well at all (and the work had been done just 5 years ago).

Here is what the IM5006 was like when I bench tested it before I started the repair.

Over the past 2 years, the number of components for a basic IM5006 rebuild has expanded from around 24 to 32, not a huge increase (although it's an almost 40% increase). After this level of repair, the IM5006 should last more than 10 years before requiring any additional work.

 All of the red arrows point to components that have been replaced.

Here is the final testing of the IM5006 after the repair has been completed.  The IM5006 is connected to 2 inside remote IS515 Stations and 1 Door Speaker (off screen).  What seems like a radio problem (static while tuning) is just poor reception at the shop that day).

Update on Tuesday, November 18, 2014 at 3:28PM by Cindy & Christopher

NuTone IM5006 Master Station: Failure Mode #2

Things fail, but not every model fails in exactly the same way.  This short video shows another NuTone IM5006 Master Station that has failed, but with different symptons than the IM5006 in the first video.

The last half of the video shows the same IM5006 Master Station after the repair has been completed.