Hifonics Brutus BXi1600D excessive current draw

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I have got another one of those BXi1600Ds.

Most of the power supply FETs were shorted, some of the outputs as well.
Removed all of the outputs and PS FETs, installed 2 new FETs in each bank in power supply.

Without output transistors amplifier draws more than 15 A of current and trips my power supply. Without rectifiers amp draws 1,3A, green Power LED lights up and relay clicks as if everything was fine.

I do not see any defective components in audio section, one Brutus which I fixed had a failed diode near HIP4080, on this amp they are fine.

Could it be shorted output filter inductor or transformer?
 
There are 10 ( or 100 ohms, do not remember which) and 1 ohm resistors near HIP4080, none of those were shorted. Also I checked rectifiers for shorts while they were still on board, but will check them again out of the board.

I suspected PS FETs drivers and removed them to check. Interesting thing is that amp continued to pull current, produced rail voltage and blew one of the PS FETs. Is that normal? I thought that without drivers PS will not work.
 
In some amps, the PNP driver transistors are required to prevent the power supply FETs from switching on. Without the PNP driver transistor and without pull-down resistors, the gates of the FETs can charge which will make the FETs conduct. This can cause them to fail.

If the power supply driver IC is operating and the PNP driver transistors are out of the circuit, the voltage isn't pulled down enough to prevent cross-conduction and the FETs will fail.

In the future, if you need to remove the drivers with power applied (but no remote voltage), install a jumper from the collector to the emitter of the PNP driver transistor. If you need to check the operation of the driver IC (remote voltage applied) with the PNP drivers out of the circuit, remove NPN driver transistors as well and install the jumper as suggested above. If you only want to prevent the FETs from being driven, you can simply remove the NPN drivers (leaving the PNP drivers). This is for drive circuits that use both NPN and PNP drivers.
 
Double checked the rectifiers, all 4 are OK. Pulled rail caps, none are shorted and my LC meter shows same number for all 4, although its max range is 200uF and these are 2200uF, but I get very similar numbers for each so I am assuming they are good.

Current draw is the same with or without HIP4080.
 
I have not looked at the gate signals on PS FETs because I figured that if they were bad then amp would draw current even without rectifiers installed, or am I mistaken?

The transistors etc. have not been replaced but there was a fixed trace, it seems to me that it is just ground trace leading nowhere, see attached picture.

Resistance between rail cap pads with caps out is 2k3 ohms.

I measured resistance between pads of output transistors, there are no shorts.
 

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The fixed trace is connected to RCA shield.

There are 15V Zeners, maybe they got hot. One opamp appears to be defective, it has 0,3V on output, 0,18V on one input and 0,10V on other input. I will replace it and see if it will have any effect on the current draw.
 
It produces clean audio now. I set the DC offset to 0,00V, nothing got even warm after playing about half an hour. But there is a strange thing which I have not had with another Brutus amps.

I use computer power supply, recently I connected two 15A rails together to get 30A out of it and installed proper power wires to it. I used to use the original wires with 2mm diameter. When switching the amp on, it trips my supply two times and powers up on the third try. Is it that while powering up it charges rail caps and the current draw exceeds 30A? It did not trip my supply before because thin wires had big enough resistance to not allow the amp to draw too much current?
 
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