NuTone Model IM5000 Selective Call Intercom System
Monday, October 29, 2012 at 7:26AM The NuTone IM5000 is the stripped-down version of NuTone's IM5006. The IM5000 was really designed to be used as an Intercom only system, however it does have a single audio input on the IM5000 control unit.
The IM5000 uses the same remote speakers and the installation layout is the same as the IM5006.
Since the IM5000 is a newer model than the IM5006, we have had fewer service requests and repairs until recently.
We have been seeing more and more IM5000 systems that are in the 8-9 year old range that are experiencing failures.
These failures present themselves in the following ways:
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The system becomes non-operational and there is often a “popping” or “clicking” noise that can be heard coming form the remote stations.
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There will be many of the LED's on the remote stations that will be dimly lit, all at the same time.
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The door chime will not operate.
The tricky part of these calls is that if some of the remote stations are disconnected from the IM5000 control unit, the remaining stations may start working again. This makes it seem to be a problem caused by a remote station, however we have found that the source of the problem is usually the IM5000 control unit.
The source of the problem seems to be a breakdown in the power supply of the IM5000 and it becomes unable to power more than 2-3 remote stations. This is a very similar problem to what happens to the IM5006.
The repair is straight forward, there are about 12 capacitors that must be replaced in the IM5000 to correct the problem, although it is prudent to replace the remaining capacitors in the circuit to insure the problem will not re-occur again in the short term.
The failure of these parts is most likely only an age related issue. An 8 year old IM5000 has accumulated 70,000 hours of in use time, which is about the expected life of the failed components.
The bench repair time for the IM5000 is about 2.0 hours, which includes the initial testing, repair and final testing. It is necessary to have at least 5-6 remote stations for proper testing.
The pictures show the components that should be replaced.
For other common problems with the IM5000, See the problems with the IM5006
Cindy & Christopher
Repairing a Lightning Damaged IM5000
A customer sent in a NuTone IM5000 Control Unit for repair and initially is seemed like it would be an ordinary repair - This turned out not to be the case at all. . .
The story that came with the IM5000 was that everything was working fine, until one day a delivery person rang the door chime then the system went crazy and everything stopped working.
This is not a particularly big IM5000 System, just 5 inside station, a door speaker and a chime module.
Initial testing showed that the IM5000 Control Module did not work correctly at all. At power up (with just 2 remote stations and a door speaker) there was a large POP from the remote speakers and that was all it did (except the red LED power indicator was on).
I started with the normal power supply rebuild (which has grown to around 30 capacitors in every unit)and tried the system again. The second attempt didn't provide the solution I wanted. Simply, nothing worked.
As I worked through the circuit board, it became fairly clear that this was a lightning damaged unit.
As I tested and replaced failed components (mostly IC's) in their circuit groups, I would retest the system and there were small incremental improvements.
It seems very likely that the lightning came in through the Door Speaker wires (this is often the case) and then the damages cascaded through the control unit. For reliability even after the IM5000 was working correctly, I replaced the remaining IC's. Units that have lightning damage can have additional failures after the unit has been repaired and put back into service, best practice is to replace the complete set of IC's.
In the end, the IM5000 worked correctly, with it's 46 newly replaced components.
When I reported to the customer about what I had found, he remember that about 3 weeks prior to the failure of the system there was a huge electrical storm and his neighbor suffered major lightning damage.
IM5000, components 
