Hifonics Brutus amp does not power up

[tobi320i]

i work on a hifonics brutus bxi 4000D class D amp.all of the power supply fets were shorted.

i replaced them all but the amp wont power up because there are no 12V on pin 12 of the 494 ic.when i solder a bridge from the remote terminal to pin 12,the amp powers up and has an idle current of 2,5A.the high-and lowside signals at the gates of the amp-fets are present.
but the speaker relays dont engage.

all of the 5 transistors which are visible in front of the power supply board,are ok

where can the error be?

 

[yoppi]

Check the remote line, to see where the fault may be. it can be an adjacent transistor near the vertical card.
Please, post a photo of the vertical card.

 

[tobi320i]

the traces are ok.the remote signal (12V) ends on the right side of the resistor R81.from that point,i soldere the bridge to pin 12 of the 494

 

[yoppi]

Check that you do not have an open or leaky transistor.

 

[tobi320i]

all of the 5 transistors which are visible in front of the power supply board,are ok

 

[yoppi]

When you connect the amplifier by that bridge you make, are the output relays activated?

 

[tobi320i]

No

 

[Perry Babin]

In the attached photo, the remote comes from the remote terminal, to the anode of D8. The cathode of D8 feeds the remote terminal of the PS driver board.

 

[tobi320i]

should the remote terminal of the PS driver board have 12V or 0V?

 

[Perry Babin]

12v

 

[tobi320i]

fault found.
the previous owner has severed two small traces,one of them was the remote to the PS driver board.dont know why he did that.

now amp works...thanks for the good tip