Rockford Fosgate power 800.2 no drive signal

[chipper]

Working on rebuilding an 800.2 completely. I’m stuck on the drive circuit. I have no output to the gate pins. I’ve replaced TL494C with a new one also replaced all four smt 2A / 1A. There’s no voltage present at the gates.

 

[Perry Babin]

DCV on each end of D2?

 

[chipper]

D2 is 13.9v. Gray end is 13.25v

 

[Perry Babin]

Do you have 13v on pins 8, 11 and 12 of both driver ICs?

Sawtooth waveform on pin 5 of both 494s?

5v on both pin 14?

Near 0v on pins 3 and 4 of both ICs?

 

[seankane]

Perry this amp uses only one 494.

 

[chipper]

Pins 8, 11, 12 have 13.25v present

Pin 14 has 4.9v

Pin 4 on 494 has 4.904v
Pin 3 - 057.1mv


Now I have a o scope I just got it not sure how to really use it it’s an 20mhz oscilloscope 9022

 

[Perry Babin]

I should have asked the board number. It appears to be a 4092. I was looking at the 3093.

Pin 4 is shutting the IC down.

Copy and paste the following list and fill in the blanks.

DCV all pins of the LM339:

Pin 1:
Pin 2:
Pin 3:
Pin 4:
Pin 5:
Pin 6:
Pin 7:
Pin 8:
Pin 9:
Pin 10:
Pin 11:
Pin 12:
Pin 13:
Pin 14:

 

[chipper]

Pin 1: 001.4mv
Pin 2: 00.9.0mv
Pin 3: 13.25v
Pin 4: 2.979v
Pin 5: 1.849v
Pin 6: 4.945v
Pin 7: 463.7mv
Pin 8: 4.392v
Pin 9: 4.945v
Pin 10: 4.945v
Pin 11: 08.24v
Pin 12: 000.3mv
Pin 13: 009.0mv
Pin 14: 009.0mv

 

[Perry Babin]

If you lift D11 and D12, does the amp power up?

See if the following page helps with the scope:
https://www.bcae1.com/oscope.htm