Blown amp. What to look for?

[CJL 10+ year member]

I got a PA BB1250.1 amp from a buddy who says it keep blowing the fuse under the hood.

I hooked it up to a battery and it got hot real fast and I heard a slight buzzing/humming noise(not the fan,it works) coming from the amp, any ideas what parts to start checking?

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[zach90z 10+ year member]

Open it up and see if you notice anything burned. If the fuses are opening it means that something in the power supply section is shorted out or in the amplifier section.

 

[CJL 10+ year member]

Had it opened,no obvious burnt components.

 

[zach90z 10+ year member]

Then you will have to test out what is bad with a volt meter.

 

[CJL 10+ year member]

zach,clear your pms.

 

[LosIsATool 5,000+ posts]

There are little transitors right in front of the fets. Look real close at those. If it is one then it needs all the fets replaced

 

[zach90z 10+ year member]

My pms are cleared i had less than 100 messages so I don't know why it wouldn't let you send a message.//content.invisioncic.com/y282845/emoticons/wow.gif.23d729408e9177caa2a0ed6a2ba6588e.gif

 

[akheathen Premium Member]

check all legs of the "q" numbered transistors clamped to the heatsink. none should read near, or at 0 ohms. the ones labeled "d" are diodes, so you will get a reading from them.

 

[BnGRacing 10+ year member]

Heard a buzzing noise? That's probably the toroid singing a bit when some current is passed thru it. That and the blowing fuses bit leads me to think there's a short on the power supply side of the amp.

 

[CJL 10+ year member]

After finally looking deeper i found the problem...

gut shot..

 

[CJL 10+ year member]

easy fix?

 

[Timmothy Web 10+ year member]

all depends on what else i took out. i working on a rubi 1000d and i just rebuilt that whole card.