help repairing a RF T5001bd

[Flashpoint GSX]

I'm an experienced installer but know very little about amplifier repair, so I was hoping you guys could help me!

This amp was poorly mounted in a vehicle and probably slid around a lot. One day it quit working. It kept blowing the fuse on the power wire.

I took the amp out, took off the cover and blew the dust/debris out with compressed air. I connected the power (unfused) and ground and everything seemed okay, but shortly after connecting the remote, all three fuses on the amp popped. Only the power LED turned on between the time the remote was connected and when the fuses blew, never the thermal or protect LEDs. I can't find any visible damage on the board or components.

Any suggestions as to where to start testing things?

[mike49504]

Id start checking the power supply fets and the outputs first off.

your multi meter set to ohms you should not read anything near 0 ohms between any of the legs on the power supply fets or the outputs,

The power supply fets and outputs are on the mesha boards ( 3 legged)

[Perry Babin]

Can you post a photo of the inside of the amp?

[Flashpoint GSX]

Originally Posted by mike49504

Id start checking the power supply fets and the outputs first off.

your multi meter set to ohms you should not read anything near 0 ohms between any of the legs on the power supply fets or the outputs,

The power supply fets and outputs are on the mesha boards ( 3 legged)

Cool, I'll start there and post results tonight.

My camera doesn't take the greatest quality pics, but I'll try to get the best pic I can.

Thank you very much

[mike49504]

Perry i think this is the amp he has

[Flashpoint GSX]

Bingo, that's it. I'm reading the article in Perry's signature to get a better understanding of all this...it helps a lot!

[Perry Babin]

That's probably it. I looked there but overlooked it.

If the fuses only blow after remote voltage is applied, the output transistors (circled in photo) have likely failed.

If you apply power again before checking the output transistors, install only a single 10 amp fuse in one of the fuse holders. Leave the other 2 empty.

[Flashpoint GSX]

The two fets shown on the lower left of the picture show very low resistance, with the middle and right legs showing a dead short between them. The two fets on the top right of the picture (labeled CR5 and CR6 on the board) are reading a short between their left and right legs, but high resistance through the middle leg. These are power supply transistors, right?

So I take it all 4 of these should be replaced. Are there other components that could have failed after these did? Or could another component have failed first, and caused the fets to fail?

[Perry Babin]

CR5 and CR6 are the rectifiers. It's normal to read 0 ohms across the outer legs. You're reading across the transformer's windings.

Read post #29 before you attempt to replace the transistors.
t30001bd schematics

It's possible that other components have failed. After replacing the outputs, power it up with the single 10 amp fuse and have all transistors clamped tightly to the heatsink. If the fuse blows, we'll have to do further troubleshooting.

You should order several PZTA56s, PZTA06s and MMBT5087s (not sure which ones are used in this amp). These are used in larger amps as drivers and, in those amps, fail when the outputs fail.

[Flashpoint GSX]

Awesome, thanks a lot! I'll post my results.