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What happens when you take your Intercom to the wrong shop for repair

I had a customer bring his IM5006 Master Station to the shop today to see if I could repair it for him.

He had recently taken it to another "repair shop" that told him they were qualified to fix it.  The original problem was the typical Power Supply Failure that I have written about before.  The other "repair shop" had the IM5006 for 4 weeks and told the owner that after several attempts they could not fix it any more than they had, and if it needed more repair it would have to be sent to another shop.

What I found when I dismantled the IM5006 was appaling.  The other "repair shop" only replaced six of the capaciotrs in the power supply circuit (the 6 easy ones) and in their attempt to "fix" the IM5006 they managed to mangle the circuit board.

The IM5006 has 2-sided circuit boards which have "through-plate" vias that connect circuit traces from one side of the board to the other.

Inside these vias there are metal sleeves which the component lead passes through and are filled with solder.  If the original component is not desoldered correctly, with tools specifically designed for this type of work, the via will remain solder to the component lead and it will be ripped from the circuit board when the component is removed.  This essentially ruins the circuit board.

By looking at the "workmanship" for the other shop, it easy to see that they have no business working on this type of board.  

When you see scratches all over the conformal coating and on the solder mask, caused by their attempt to desolder the pad, you know that something is very wrong.

With any luck the damage to this board is not as bad as I fear.  If the vias have been pulled through the board, it will be necessary to re-sleeve the vias (not a fun job).

When you see big blobs of solder on a solder pad, you can tell that person doing the work has no business using a soldering iron.


More to come. . . 




Waiting to have your Intercom repaired will cost you more money - sometimes -

Last week I had a customer send in her IM3003 for repair.  It had failed about 4 years ago and because she couldn't find anyone to repair it all of the volume controls were turned down to mask the loud hum on the speakers.

When I received the IM3003 I verified that it had a failed power supply and set off to rebuild it.  My method of repairing any intercom Master Station is to verify all of its problems, once the master works well enough to properly evaluate it.

Once I had the power supply rebuilt, I reconnected this IM3003 to my bench "system" which consists of 3 remote inside station and a entry door speaker.  What I found were the following problems:

1.  There were no intercom functions, at all.

2.  The IA29 chime module did not work.

3.  The clock display was not as brightly lit as it should have been and it flickered somewhat.

4.  The radio would play for about 10 minutes then slowly fade away.

There was obviously a lot more wrong than a failed power supply.  

What typically happens is when the power supply fails and the master is left in that condition for a long time (years) it progressively gets worse and worse.  The damage (from incorrect voltages) spreads throughout the master and more and more things will need to be repaired.  I have seen some masters where the amplifier IC needs to be replaced because it has completely failed from being run so very hot.

So, waiting will cost you more money in the end when you decided to finally get your intercom repaired.  This IM3003 repair cost and additional $30.00 in parts and labor to sort all of the problems.

In the end everything worked well and the customer was happy to have her intercom back.




Discontinued NuTone Intercom Models: IMA3303 

Every week I have five or six homeowners contact me looking for a NuTone IMA3303 Master Station to replace their broken IM3003.  The conversation is almost always the same, they searched around online and found many sites that recommend the IMA3303 as a direct replacement for their older IM3003.

While the IMA3303 was a direct replacement for the IM3003, the IMA3303 has been discontinued and out of production since 2008.  When NuTone announced that the IMA3303 was being discontinued, they held back some units which were to be used as in-warranty replacements for recently sold masters.

NuTone sold the remaining IMA3303 master stations on their own web site and through eBay until the supply was exhausted.  If a Distributor or Dealer wanted a unit, there were no special deals, they would have to buy it from NuTone just like a consumer.  The supply of IMA3303's was exhausted by the beginning of 2011.

There is always a lot of outdated information on the internet and sites that show IMA3303 as a "in-Stock" item usually don't really have any at all.  Everyone should make a phone to to any dealer to verify that they actually have the item they show on line.

I have seen some sellers on eBay selling IMA3303's for as much as $850.00 which is more than the final retail price in 2008.  Remember that to use a IMA3303 as a replacement for a IM3003 either the wall housing needs to be replaced or at a minimum the original transformer will need to be replaced and a second transformer will need to be added.  IMA3303 require 2 NuTone 301T transformers, which are now also discontinued.

I'm not sure if spending $800.00 to $900.00 for a discontinued IMA3303 is a good value considering that the average IM3003 can be repaired and rebuilt for around $275.00




Lightening Damaged Intercoms

Here in California we don't have a real problem with lightening and lightening storms.  I think that people from other parts of the country would laugh at the kind of lightening we have.

I've talked with so many people from the Mid-West, Southern States and the East Coast where lightening storms are a real problem.  I spoke with a homeowner last week who had a actual lightening strike on the roof of his home, causing thousand of dollars of damage.

Lightening damage to electronics is real and it does effect intercom master stations all the time.  The real problem with lightening damage is that it does not follow any particular pattern in regards to where the damage occurs.

Lightening can damage components that normally would never fail on their own, it is particularly hard on Integrated Circuits (IC's) which almost never fail on there own in intercoms.  Sometimes the damage is subtle, just a random amount of static in the background noise of the system, or it can be strange operational problems that don't follow any normal patterns for that model.

Newer models like the IM(A)3303 and IM(A)4406 use micro-controllers and logic IC's to manage the operations of the system.  If these micro-controllers become damaged due to lightening, the set is unrepairable unless a replacement board can be found.




Can you repair your own Intercom Master Station?

The short answer to this question is usually No.

While many times a Master Station will only need a typical repair, but there are just as many times that it will need a more extensive repair.  Why is this?

I think it is because many owners are unaware of how their model of intercom system was designed to function.  However it worked when they moved into their home is how they expect it to work.  When the system has a more dramatic problem and it becomes obvious that it needs to be repaired, they are unaware that the master station actually has more problems that need to be solved.

I see many master stations that have operational problems that aren't included in the list of problems that the owner has provided.  Of course all of the problems need to be repaired before the unit is returned to its owner.

While a hobbyist might be able to replace the capacitors in a failed power supply, they usually are not equipped to solve more technically involved problems with their unit.  It's very disappointing to have spent the time to order components and install them, just to find out that the master station still does not work correctly.  

We receive many sets each month that have had uncompleted repairs started by other shops or homeowners.  These units always need more time and attention to repair.  Figuring out what was done by someone else and often redoing the work is time consuming.

Also, since replacement boards are rare (and expensive) extreme care must be taken to not damage the boards when they are reworked.

Unless you have experience in repairing electronics, it is often best to leave it to the established NuTone Service Center.