Control board voltage problem

[roccus]

Then I wouldn't have a clue...

ahh but I would and I have parts coming out my butt for them

 

[laatsch55]

I see....

 

[Gepetto]

Checked out pad 12 on right and left channel right channel is good -83V but right channel is +3 volt looked at pico fuses on right channel backplane and the B- fuse is open... I know I don't have any of these around here so looks like my amp will be out of commission for at least another week or so to get replacement fuse

Tack a 10 ohm 1/4W resistor on top of the existing fuse until you get your replacement parts Ray. If you blow the resistor, then you have other issues to troubleshoot. If not, the fuse replacement will bring you back to life.

 

[roccus]

Tack a 10 ohm 1/4W resistor on top of the existing fuse until you get your replacement parts Ray. If you blow the resistor, then you have other issues to troubleshoot. If not, the fuse replacement will bring you back to life.

Very cool thanks Joe will do been bumming for a few weeks now with it being down waiting for this part than that part now a fuse.... the stock 400 has been getting me through... maybe once wopl 400 is sorted may but some wopl parts in the stock one she deserves it want to upgrade wifes stereo in house but a 400 is way over kill for the EPI 100's I set up for her...

 

[laatsch55]

Nah......good clean power is never overkill....

 

[roccus]

Tack a 10 ohm 1/4W resistor on top of the existing fuse until you get your replacement parts Ray. If you blow the resistor, then you have other issues to troubleshoot. If not, the fuse replacement will bring you back to life.

With resistor jumper got my voltage back on pad 12 resistor did not burn up but still something not right on the -15V test pin I'm getting -0.98V there... voltage to D82 looks good but voltage on R55 and R53 is low, so back to VR2?

 

[laatsch55]

Are you getting minus rail voltage out of Q2?

 

[roccus]

Are you getting minus rail voltage out of Q2?

Q2 pin 1 -15V, pin 2 -81V, pin 3 -0.98V... very low voltage going to VR2

Edit.. sorry looking at Q2 upside down here... pin 1 is -0.98V pin 3 is -15V

 

[laatsch55]

What are you getting on the 3 pins of VR2?

 

[roccus]

What are you getting on the 3 pins of VR2?

-

Pin A -1.5V, Pin B -0.86V, Pin C 0V

 

[laatsch55]

Got an open diode between the 2??

 

[roccus]

Got an open diode between the 2??

Well I notice D81 has -1.5V going in but 0V going out.. D82 looks ok

 

[roccus]

Well I notice D81 has -1.5V going in but 0V going out.. D82 looks ok

R55 has -81V going in and -1.5V going out

 

[Gepetto]

R55 has -81V going in and -1.5V going out

Yes you are back to VR2 Ray

 

[Gepetto]

-

Pin A -1.5V, Pin B -0.86V, Pin C 0V

Pin B as you call it should be -13.1V, not -0.86V. Lift one end of D81 to confirm it is VR2 and not D81. D81 is very unlikely as it does nothing in the circuit unless a fault causing VR2 to fail open occurs.

 

[roccus]

Yes you are back to VR2 Ray

Got to order those then too... getting ready to dig a hole in the back yard and bury this thing