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.