Uber expensive repair at United Radio

A lot of very good points made by many here.  Very good posts.

As some mentioned, exactly how long does it take to diagnose where exactly the problem is?  That actually takes more time than pretty much anything else.  The OP mentioned two chipsets.  Well, how long did it take to find that the problem was the two chipsets? 

Typically, unless the amp displays error codes like modern cars, the tech has to start in certain sequence and move forward.

For example, disconnect everything from the power supplies and see if the power supplies are actually working.

If so, connect one side of the amp to the power supply, see if it works, then disconnect that side and connect the other.  Slowly bring up the voltage.

These are just small examples. 

Diagnose the protection circuitry, etc.  yep, I hate to tell you but, these take some time.  Unless I knew exactly what the problem originally was, I would take my time and go in sequence.
So, the time spent, actually does make sense to me.

I work on electronics all the time and I also restore classic cars and I work on cars also.

I own and restored a 1983 Volvo 244 Turbo.  It had a low oil pressure reading on the gauge and the idiot light.  Know what the problem was?  wasn't the gauge or wiring, wasn't the oil pump, bearings, etc.  it was a stupid five cents o ring on the oil pickup tube.  yep.  had to drop the oil pan (stupidly difficult on this car), had to move the steering rack and lots of other things to get that oil pan off, remove the oil pump tube.

This took an entire weekend.

So, having worked on (and still to) and repair and upgrade audio equipment, I can tell you that although it took them some time, I can see why it might have.

enjoy

@dasign I get you.

However, knowing/diagnosing what area in an amp is the problem is not the same as knowing what circuit(s) is the culprit.

I can determine that the protection board is the problem, but, unless (like most repair shops), I replace the entire circuit board with a new one, I decide to take the time (and yes this really does take time) to find out which components are the culprit (in this case, two chips), then, this will take substantial time.

14 hours is not unreasonable.  People are commenting as if it is obvious that the two chips were the problem on that circuit.  It could just as well have been capacitors, transistors, or worse diodes.  you (as a technician) have to take the time and use standard testing techniques to find out.

Again, this is why many replace the entire circuit board instead of taking the time to find the actual component and remove and replace it.  In many cases, that circuit board (stuffed by-the-way) is unobtainable.  So, you are left with finding the actual failed circuit component and fixing it.

I have several units where I know which circuit board is at fault.  But, this circuit board has all kinds of components on it that could be the problem, including on-board mounted integrated circuits.  And very small ones at that.  Try, just try to un-solder those and put new ones on.  They are a bear.

Ever try to repair a Mark Levinson 23.5 amp?  Great amp even today, but that amp is a serious PITA to work on.

My point?  unless you actually worked on that particular unit yourself and had the same problem, you have no clue how difficult is would be to diagnose (not just the culprit circuit board, but the actual failed component on that particular circuit board), remove the failed items (on-board mounted circuits are a royal pain) and install the new ones, test it and make sure that it works.

enjoy