PowerAcoustic BAMF5500, becomes hot
I have repaired BAMF5500. It was a problem with power supply mosfet.
But, when I tested the amp, 3 mosfets IRFP264 (q331-q333) in main amplifier become hot. Output coils becomes hot too.
I switch on the amp series a 12v lamp. The lamp lights up a half of power. I measured the ambient current. It was 2A / 12V.
When I unplug digital driver board, the lamp turns off.
I have no schematic of digital driver (it includes ir2110).
The amp plays the music normaly.
But is it normal? It seems too high ambient current.
Which component is faulty?
Help me please.
PS:Sorry for my English.
Were the outputs clamped to the heatsink?
How hot did they get and how long did it take them to get that hot?
Were you driving a load with the amp when they got hot?
Do you have a scope?
Does twisting the inductors make a difference in the current draw at idle?
The outputs were not clamped to the heatsink.
Nearly 3 minutes. I think 60 C.
The load is disconnected.
I have a scope.There is a squre 66kHz on outputs G-S.
Inductors are soldered. I can not twist them.
It seems to be OK, but I don't like that outputs Q311-313 are cold. And Q331-333 come warm.
It looks like it's OK. I'm assuming that the current draw isn't significantly more without the current limiter.
Clamps all semiconductors to the heatsink and drive the amp hard. Monitor the temperature behind/under the output FETs. If the ones that are getting warm now don't heat up faster than the others, It's likely OK.
Thanks for fast answer!
Mate, give me your e-mail and I will provide you with the schematics.
Bear in your mind that this amps is overrated. The best it can deliver is about 700W @ 4 Ohm, 1400 @ 2 Ohm and 1700 @ 1 Ohm load. Do not consider installing higher rated fuses since the powe supply cannot deliver more power.
Moreover, the MOSFETS in the power supply IRFP064N are very weak even for the output power of 1700W. I would suggest replacement with 60V / 140A equivalents. I can tell you a little bit later which MOSFETS are appropriate.
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