Rocford punch 500-2 2007 model.

[rhempz01]

It has to be on the left channel board I know that so I changed a few of the 3906-04's no change. And all of the components look ok to me. I'm still searching. Thanks Perry

 

[rhempz01]

No I did not reset the bias Perry. I left it glued. I'll do that and post back. Do I slowly turn it up until problem and back it off?

 

[rhempz01]

I turned them all the way counter clockwise still the same output issue. I started comparing the DC on the board vrs the other.

 

[Perry Babin]

The suggestion for biasing was before you posted the DC offset problem. Bias won't cause DC offset in these amps if the bias setting is the only problem.

You generally cannot use the original bias setting after replacing output FETs. After replacing outputs, set the bias fully off (CCW in these amps) before powering the amp on.

 

[rhempz01]

Ok so I fiqured it out perry. The fqa36p15 I used a eBay seller China and they suck. I went back to the old ones both channels work on those chips. Any suggestions on where can I buy these chips or chips that are compatible. Mouser and digikey say back ordered.?

 

[Perry Babin]

https://octopart.com/search?q=fqa36p15+

 

[rhempz01]

Thanks Perry i ended up buying 20 from arrow? Idk they come by the 6th. Thanks..

 

[rhempz01]

So the transistors I received from arrow were authentic and nice. Worked great, one question, should I set the bias settings as high as possible or as low as possible? I just need a better understanding of setting them

 

[Perry Babin]

Low unless you have a reason to set them high. Higher bias will make the amp run higher, often with no benefits.

Set them like this:
http://www.bcae1.com/temp/ausettingbias.swf