Rockford t600-2 distortion

[punch45x2]

Hi guys. Working on a rockford t600-2 both channels play but are slightly distorted. The amp will play bridged but very low volume. Where should I begin?

 

[Perry Babin]

Post a photo of both channels displayed at the same time.

 

[punch45x2]

Of drive signal or of a sign wave through the outputs

 

[Perry Babin]

I want to see the distortion on the output of the amp, both channels displayed at the same time.

Images with no load, stereo loading and bridged loading would be useful.

 

[punch45x2]

Right=ch1 on scope.
Left= ch2 on scope
No load

 

[punch45x2]

Right=ch1 on scope.
Left= ch2 on scope
4 ohm stereo

 

[punch45x2]

Bridged no load

 

[punch45x2]

Bridged 4ohm [2 ohm per channel)

 

[Perry Babin]

Set your scope:

2ms
5v/div
DC coupling
each trace aligned to the center of the display (vertically)
100Hz test tone
drive the amp with enough signal so that the output swings to about ±3/4 of the display.

 

[punch45x2]

With or without load

 

[Perry Babin]

With

 

[punch45x2]

100hz sine. 4 ohm load ch1 left ch2 is right.

 

[punch45x2]

Looks like right channel has a drive issue

 

[Perry Babin]

Are you sure that the 0.1 ohm source resistors are within tolerance?

I'm not sure about this board but a board from a similar amp uses D204 and D205 on the driver boards in the over-current protection circuit. Lifting them will tell you whether the problem is in the protection circuit or in the drive circuit.

 

[punch45x2]

I have a d205 and d204 on each ab output card.

 

[Perry Babin]

Can you lift them for the bad channel to see if that makes a difference?

 

[punch45x2]

Lifted pin 3 and no change on either card.

 

[Perry Babin]

Is there a pin on the audio driver board header that is initially (on remote application) at 13v then after a few seconds, goes to about -7v?