Defect Transistors in Hifonics Brutus BX1500D

[Perry Babin]

Is there any DC on any of the speaker terminals?

Place the black meter probe on the amplifier's ground terminal. Place the red meter probe on the point where you need to measure the voltage.

 

[seedyrom2003]

With 4080 removed, all 4 outputs including ground are reading ~6.14v with meter set in DC. Source voltage is set at 12.5v.

 

[Perry Babin]

It doesn't appear that you have any shorted outputs. Replacing the 4080 may be all that you need to do.

 

[seedyrom2003]

4080's arrived today, same problem as before.. power comes on to a green light, relay clicks and coil squeals then goes into protect, process repeats.

 

[Perry Babin]

Do you have a load on the amp?

Does the protect LED light or does the power LED go red?

 

[seedyrom2003]

No load on the amp, powers on.. the power light (red) stays on. The protect light switches back and forth from green to red

 

[Perry Babin]

Are you sure you don't have the power/protect lights reversed. I don't think the protect light can go green.

 

[seedyrom2003]

YouTube - VID00152

That should help, sorry for the confusion

 

[Perry Babin]

Twist/push/pull on the inductors and the transformers when it's going into protect mode to see if it changes the way the amp behaves.

 

[seedyrom2003]

If I push on the coil thats squealing it will stay on.. albeit the squeal doesnt go away could this be the coil?

 

[Perry Babin]

Which one is it?

 

[seedyrom2003]

YouTube - VID00155

It is intermittent though.. sometimes itll stay on other times pushing the coil seems to have no effect.

 

[Perry Babin]

It may not be the transformer. Pushing on it makes the entire board flex. It could be almost anything on the board if twisting the transformer makes no difference.

Remove the clamps from the output transistors (disconnect amp from power supply). Lift the transistors and move the body of the output transistors side to side. Are any legs on them broken. Look VERY closely where the legs of the transistors go into the bodies of the transistors. Sometimes they break just inside the body.

 

[seedyrom2003]

Those were the ones I replaced already with the non-z ones. I havent purchased the 3710Zs yet. The legs are fine.. should I purchase those new and report back?

 

[Perry Babin]

There's no point in doing anything else until you get the outputs replaced.

 

[seedyrom2003]

Brutal honesty haha. I totally forgot you said to put those Z's in.

Digi-Key - IRF3710ZPBF-ND (Manufacturer - IRF3710ZPBF)

That the correct part?

 

[Perry Babin]

Yes.

 

[seedyrom2003]

Z's installed, problem still exists. This time the amp seems to do its cycle faster.

 

[Perry Babin]

Is pin 3 on the 4080 going from low to high when it's cycling?

 

[seedyrom2003]

The relay doesnt click in as fast before it goes into protect now.. If im correct pin 3 gets to .4v before it cycles again. I have double checked all the mosfets on the board and none are showing a short other than the ones connected to the coil. With the 4080 out the relay clicks over and light stays green as if its functioning like it did before.