ppi a1200 need help

[integrite07]

I have an amp to fix its a ppi a1200 it had some blown fets i replaced them and power up sound is excellant and loud but i have a squealing coming from the toroid i believe any suggestions? ive resolder all the output fets, snap caps, and transformer.
Thanks for your help

 

[Perry Babin]

Does twisting the transformer make a difference?

Is the noise so bad that it will be audible when the amp is installed in the vehicle?

 

[integrite07]

well i cant tell if twisting does anything i have to have the bottom plate on to hold down the fets. The noise if its installed you cannot here it if the bass is turned up. but test benching it with power supply and battery while the amp is in front of me i can here the whine.

 

[Perry Babin]

This is common for a lot of switching power supplies and doesn't generally indicate that there is a problem.

If you're going to work on PPI amps, you need to build clamps so that you can work on them with the cover removed.

 

[integrite07]

Yes that is on my list to do. Ive just been infatuated with these amps i like the way they sound. i know for sure that it is coming from the toroid. Should i list some pics?

 

[Perry Babin]

Photos showing what?

 

[integrite07]

of anything guess not. any suggestions after i make the clamps if moving the transformer doesnt do anything?

 

[integrite07]

Got it all taken care of thanks Perry for your help