Alpine PDX1.1000 powers on, no audio (IR2010s HELP)

[mild2wild]

When first powered on, the - speaker terminal reads as high as -0.62 and the + terminal reads as high as 0.22.

With a 4 ohm speaker connected, they both read -0.04.

 

[Perry Babin]

Is the input to the op-amp swinging well over the 0.04v?

Measure on the input pins of the op-amp (on a component directly connected to those pins if it's easier, D9701, D9702).

Do you get a square wave on the output of the op-amp?

 

[mild2wild]

Pic1 is R9701 with no signal
Pic2 is R9701 with 100hz at volume 35(out of 62)

 

[Perry Babin]

When posting images (take the scope off of auto) and set it to display 3-4 cycles with the amplitude covering about 3/4 of the vertical height of the display (from the center reference).

Measure on the diodes.

 

[mild2wild]

Which diodes? What board designation?

 

[Perry Babin]

From post 142:
D9701, D9702

 

[mild2wild]

Pic1 is signal on R9701/2, D9701/2, and both inputs of IC9701

Pic2 is the square wave output of IC9701 up to the 1k resistor R9713

Pic3 is the side of R9713 that connects to Q9701

 

[Perry Babin]

Does lifting D4501/4502 make a difference after R9713?

Are the transistors Q9701/9702 in or out of the circuit?

 

[mild2wild]

Lifting D4501/4502 allows the signal at R9713 to pass through unhindered.

Q9701/9702 are currently out of the circuit. The voltages at the pads are:
Leg1 5.01
Leg2 -45.89
Leg3 2.53

Pic1 is with 100hz signal at R9701 at volume 23( that is the threshold where the spikes occur as it is only a flat line at 0v at any volume lower)

Pic2 is at volume 55.

I reinstalled Q9701/9702 and am getting a square wave on Pin1 of IC9702/9704 with D4501/4502 lifted.

 

[Perry Babin]

Reinstall the transistors to see if the drive signal makes it to the collector.

Do both outputs of the op-amp look approximately the same?

 

[mild2wild]

Correction. Not getting square wave on Pin1 of IC9702/9704. Square wave is on legs 1 and 3.

Signal on R9713/9714 both look identical.

 

[Perry Babin]

Do you have equal input signals on both D9701 and D9702?

 

[mild2wild]

Waveforms and voltages on D9701/9702 are identical.

 

[Perry Babin]

If you have the same input to both channels of the op-amp and output on only one, the op-amp could be (is likely) defective.

In my amp, one channel is weak and produces a waveform similar to yours. The other channel is symmetrical and relatively square.

 

[mild2wild]

In my amp both outputs of the NJM2137 are identical, all the way up to Q9701/9702. My problem was getting the square wave past R9713/9714, which lifting D9501/9502 allows. I now have the square wave on both the base and emitter of Q9701/9702.

 

[Perry Babin]

Did you reinstall the transistors since you lifted the diodes?

 

[mild2wild]

Yes. Q9701/9702 are installed

 

[Perry Babin]

And still no drive signal on the collectors?

 

[mild2wild]

Getting a straight line on the collectors of Q9701/9702. I have square wave on the base and emitter.

Currently, the M1000 and the PDX1000 are behaving exactly the same. Square wave on base and emitter, but straight line on the collectors.

 

[Perry Babin]

I missed post 149. You posted while I was typing. Sorry I asked about things posted there.

Why did you lose the signal on the input of the inverters between post 149 and when you no longer had it?