optic drive 700x2

megael9

Member
2009-10-13 9:36 pm
here is the picture.
also, i purchased the repair tutorial a long time ago, can I download the latest version?
thank you
 

Attachments

  • opti drive.jpg
    opti drive.jpg
    1,011 KB · Views: 53

megael9

Member
2009-10-13 9:36 pm
i took out every semiconductor, and i went back as far as taking out of the board q202, q203, q204 and q 205.
all semiconductor checked ok, and no voltage at the output up to this point, but it is kind of difficult to trace back from here.
are q601, and q602 part of what i need to check?
 
I can't really read the numbers on the board. I'm assuming that the 600 series are something like the regulators.

I'm assuming that Q202-205 are the small transistors that make up the two differential amplifiers. Is that correct?


Are you saying that with all semis but the 4 above in the circuit that there is 0v DC on the output of that channel?

Is there excessive DC driving into the differential amp stage?

Did you check those 4 transistors (as well as any you pulled) for leakage and open junctions?

Is there a Q201 that's used for muting?
 

megael9

Member
2009-10-13 9:36 pm
I pulled out all semis from the board and tested them. And while I pulled them out of the circuit ( by sets ) I tested for voltage at the output and there was no voltage at the speakers terminals.
I also pulled out Q601 and Q602 and there was voltage at the speakers terminals.
Both transistors checkered Ok.
About Q201, I don’t see it on this board.
 

megael9

Member
2009-10-13 9:36 pm
i found this schematic on the web, the components location numbers match on a 95%, i was able to confirm that the pre amp for both channels are working fine, and it looks like the driver circuit is the problem, however, except for the output transistors, i exchanged all driver circuit components from the good channel to the bad one and vice versa, and the problem remains on the bad channel. i also noticed that the bad channel have a square wave at its output, instead of audio signal. the output filter composed of c190 and r296 is working ok
 

Attachments

  • lanzar_opti500x2.pdf
    778.8 KB · Views: 35