Hifonics Brutus BRZ1700.1D blows power capacitor

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Evening guys, I'm working on an Hifonics it's periodically blows the power cap 100v 2200uf. The owner says it's the second time it's giving the same problem, after my teardown and test I had one bad fet (short) that pulled itself from the circuit board, I change the two bad caps (one was faulty other in tolerance but I put two same from an Orion amp and replaced the fet.
Working voltages are 64 -/+ when up, you'll switched off and on again and youre getting 128v increased between the cap again.
Another noticed is when disconnect speaker and drive the gain up it will cycle power and protect until minimum gain is reach.
 

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The ones in the yellow rectangle WILL fail. I replace them before I do any other troubleshooting.

You generally don't have to remove the driver board. Stand the amp on end so that the driver board is flat and replace those transistors.
 

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I've pull the board because I couldn't get a proper angle to remove the usual suspects from the board however I've check the transistors in fact all the 1D's the 2D's and even the larger P2D's and didn't see any short open or leakage on the transistors.
Is it possible that the DMM test will differ from when the transistors or energized or under load? Should I just go ahead and make a replacement even tho I assume they are good?
What about the Q28xx bank of transistors should I checked them also?
As I said before the amp will power up and play great but at random times it will produce an over volt on the power caps (outer ends). And I've notice if the amp is preset gain above half it only cycles the power/protect LEDs repeatedly.
 
I've seen transistors that checked OK with a multimeter but would not work properly in a class D circuit.

I replace the 2 1D transistors whether they're causing problems or not. unless that amp has very few hours on it, you likely saw discoloration of the board under them.

The only components that I've seen fail on those amps (more than a random failure) is the two 1D transistors and the op-amp closest to the top of the board. I had an SMD capacitor crack but that was a 1-off failure.

I don't have an easy way to check the drive circuit since I've never run into any problems with these amps other than what was mentioned above. You'll have to look at the signals on the gates to see if you're getting a clean signal that's about 10v in amplitude (referenced to the source leg).
 
Ok this is my final question for this thread....
I sometimes have audio driver boards that I want to test in an amp to set them aside knowing what is working or not, sometimes I may also have to solder and resolder cards multiple times, is there any negative effects on extending wires from board to card legs (not exceeding 3-4inches wire length), will that affect waveforms, drive signals or stability?
Or is there any inline single socket that you know of that can make repairing daughter cards with less hassle?
 
Extending the connections hasn't caused any significant problems for me. It may make a signal a bit noisier but for basic testing, it's generally OK.

You can use sockets but be aware that an intermittent connection in a socket can cause FETs to fail. If you use sockets, use sockets with gold plated contacts. You should also realize that plugging and unplugging socketed driver boards can cause FETs to fail if it's done while the rail caps are charged.
 
Good afternoon guys, the amps has done the same thing and it wasn't been played extensively according to the customer.
I don't know if I should start a new thread. I've repaired the audio riser but I didn't find any significant problems but was instructed to change the smd's.
Is there a problem otherwise that I'm just not seeing?
 
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