Orion XTR PRO 2400

[Perry Babin]

Either the LM361 is defective or something is loading it too heavily.

 

[caraudioguy2100]

Which one is the LM361 the one marked F16 or B52?

 

[Perry Babin]

The one nearest the 3-pin connector. The output pins go straight to the connector.

 

[caraudioguy2100]

I will order a new one and post results once it comes in

 

[caraudioguy2100]

After removing the audio driverboards .

Here is what I get on the 3 pin connector now

So I’m guessing it’s a driver issue

 

[Perry Babin]

Connect a 1k resistor between the center terminal of 3-pin connector and the outer terminals. Does the signal look the same on each output?

 

[caraudioguy2100]

With a 1k resistor in place I get the same waveforms on both outputs of the 3 pin connector

 

[Perry Babin]

Reinstall the driver boards one at a time, only soldering the 3-pin connector. Does one board load the drive differently than the other?

 

[caraudioguy2100]

I replaced all of the drivers .

Here is what I get on the 3 pin connector now .

Do these drive waves look correct or do I still have a problem possibly a bad LM361?
Scope settings are 2us 2volts /div

 

[Perry Babin]

What's the DC voltage on the power supply pis of the 361 on the output side of the IC?

 

[caraudioguy2100]

Is the voltage you need the output pins or the strobe pins of that ic ?

 

[caraudioguy2100]

Not sure what voltages you need but here is the voltages on the LM361

Pin 1:11.87
Pin 2:0.00
Pin 3:0.00
Pin 4:-0.07
Pin 5:0.00
Pin 6:-11.78
Pin 7:0.00
Pin 8:2.76
Pin 9:0.23
Pin 10:-1.89
Pin 11:0.26
Pin 12:0.00
Pin 13:2.79
Pin 14:2.79

 

[Perry Babin]

The supply voltage look OK.

Going back to post 47. You stated that you got the same signal on both outputs. But did you get the same waveform as you had on post 45?

 

[caraudioguy2100]

First pic is with the audio driverboards removed and the 2nd pic is with the audio driverboards installed.

Scope settings are 2us 2volts/div in both pics .

Post 45 the top edge of the waveform looked better with no audio boards installed post 47 appears to have a curve not sure if this is normal or not .

 

[Perry Babin]

Was the signal identical to the one above on the left with the 1 k resistors?

 

[caraudioguy2100]

I don’t get this amp .

The power supply was fine now all of a sudden it’s blowing the power supply fets and I don’t get drive signal even on pins 9 and 10 of the 494

Any ideas on where to go from here

 

[Perry Babin]

You need to look at the voltage on the various terminals of the 494 to see why it's not producing pulses.

 

[caraudioguy2100]

Here is what I get on the 494

Pin 1:4.99
Pin 2:0.05
Pin 3:0.00
Pin 4:1.47
Pin 5:3.73
Pin 6:0.00
Pin 7:13.47
Pin 8:4.96
Pin 9:5.30
Pin 10.5:30
Pin 11:13.47
Pin 12:13.47
Pin 13:4.99
Pin 14:4.99
Pin 15:4.99
Pin 16:0.00

 

[Perry Babin]

There's nothing wrong with the drive on that IC.

 

[caraudioguy2100]

Why would it blow every single power supply fet on the board 1 by 1 ?

The drive on pins 9/10 is the same drive I get on the gate pads for the fets and it blows fets instantly