Boston GT-42, info needed

[FireII]

Customer brought in a Boston GT-42, he said that when he powered his amp OFF sparks and smoke came about, I'm kinda puzzled as to what could have caused this to happen when powering an amp off except for pure coincedence. Anyways, every psfet is burned beyond recognition and there is some damage to the board but I believe it can be repaired, I've yet to determind the cause of the ps failure, to both power supplies but I need to know what I can replace the psfets with to get the amp to run. Any help would be appriciated.

Thanks,
Greg

[FireII]

I also need to know the part numbers for the ps drivers coming off of the sg3525 so that I can pull a datasheet on them, they are not legible.

Thanks,
Greg

[Perry Babin]

I don't have any information on this amp. Have you tried cleaning the faces of the transistors (acetone) and trying to piece together the part numbers from several to determine the part number?

Applying heatsink compound and then removing the excess can often help bring out the markings.

If you can post a photo of the power supply section of the amp, it may be helpful.

[FireII]

Originally Posted by Perry Babin

I don't have any information on this amp. Have you tried cleaning the faces of the transistors (acetone) and trying to piece together the part numbers from several to determine the part number?

Applying heatsink compound and then removing the excess can often help bring out the markings.

If you can post a photo of the power supply section of the amp, it may be helpful.

I was able to make out a PS FET, they are P60NF06, which are available, the gate resistors are 56ohm. I still cannot make out the drivers, all four of which are toast as well. I've included a picture as requested.

[Perry Babin]

Are the 4 surface mount transistors on the corner of the board the driver transistors?

Can you read any of the numbers on the face of them?

[FireII]

Originally Posted by Perry Babin

Are the 4 surface mount transistors on the corner of the board the driver transistors?

Can you read any of the numbers on the face of them?

Yes, those are the drivers. On only one of them can I see, what looks like, BL 534, but I'm not 100%.

[Perry Babin]

Does the center leg on 2 of them go to ground and the center leg on the other two go to B+?

[FireII]

Originally Posted by Perry Babin

Does the center leg on 2 of them go to ground and the center leg on the other two go to B+?

I'll have to pull them to find out.

[Perry Babin]

You don't have to pull them. Use your multimeter.

[FireII]

Originally Posted by Perry Babin

Does the center leg on 2 of them go to ground and the center leg on the other two go to B+?

Perry,
Yes, this is correct.