Audio Gods AG 7000.1D

[chrisg4]

Ok, so there's an issue on the driver board?

 

[Perry Babin]

You may not be getting the drive signal to the driver board.

 

[chrisg4]

Hi Perry,

I found the audio signal on the driver board at R32(blue) but it doesnt appear on the other side of the resistor

An externally hosted image should be here but it was not working when we last tested it.

 

[Perry Babin]

Does the side of the resistor read 0 ohms to any terminal of the TL072?

 

[chrisg4]

Yes,

Getting a 0 ohm reading on Pin 2

 

[Perry Babin]

You should see signal there.

Are the outputs out of the amp right now?

 

[chrisg4]

Yes, there signal is there.

haven't installed the outputs yet.

 

[Perry Babin]

OK, if driven hard enough, you should see signal on the output of the TL072 and the output of the LM311.

 

[chrisg4]

I'm using a signal generator app on my phone

 

[Perry Babin]

If the gain is max'd, the phone may provide enough signal. Use a low frequency of 50-100Hz.

 

[chrisg4]

did some searching on the driver board, found no -5v present, traced it back to an inductor that may be bad.

 

[chrisg4]

Replacing the inductor seems to have sorted the drive issue, have drive present on both high and low side. the low side drive seems drive wave is smaller than the high side.

 

[Perry Babin]

What is the amplitude of the high and low side drive signals?

 

[chrisg4]

Hi,

Probe - x10
2v/div
2ms/div


high side - 10v

low side - 4v

 

[Perry Babin]

Do you have 12v across the collectors for both the high and low side driver transistor pairs on the driver board?

 

[chrisg4]

do i measure the across npn pair and pnp pair?

 

[Perry Babin]

Vertically. One NPN to one PNP.

 

[chrisg4]

12v across 1st pair

10v across 2nd pair

 

[Perry Babin]

Assuming that the 10v is for the low-side...

The 10v probably won't explain the entire difference but you need to check the output of the 7812 regulator. Place the black probe on its ground terminal and measure the input and output voltage for that regulator.

 

[chrisg4]

7812
In - 17.1v
out - 12.2v