820-00430 - sound with optical output

[Palhano]

Imac with intermittent sound. Sometimes the sound comes out of the speakers normally and then switches to the optical output. The volume icon shows a prohibition sign.

I tried changing the P2 connector 3 times, but the problem persists. I searched the forum for alternatives to "kill" the P2 output by removing a resistor. But I couldn't identify which resistor in this model.

 

[2informaticos]

Check J6600's pins 16/18/20 behavior.
Also monitor DFET_OPENCH/US lines.
Did you replace entire audio connector board?

 

[Palhano]

I waited for the sound problem to appear and compared pins 16/18/20 with another board!

In diode mode, pin 20 was giving 0.120, while on the good board it was 1.700. I replaced C6602 and L6607, now it's the same and the sound is working. I'll keep testing to see if the sound fails again. I'll get back to you with news.

 

[Palhano]

It seems the problem has been solved. Sound has been working for a few days now.