Hi I have been working on my sony sa-wmsp1 powered subwoofer for over a month now and I can't seem to find the problem. It has power but no sound. I have replaced the amp. # LM3886TF and still no good. Can you guys take a look at my Schematics and see what you can find and advise me Please.
The speaker works fine as a mater of fact I even get a thump through the speaker when I turn on the power. I checked the voltages at pin 1, 3 and 4 I have voltage at 1 and 3 but not at 4.
Here is the pdf again. View attachment schematics.pdf
You know I would do that but then what would I have learned other than someone else fixed it. I would like the knowledge for self experince. Now I changed out the rectifier bridge D401 and that made no change.
If you guys could assist me with tracing out the circuit it would be greatly appriciated.
Is there about -40V at the negative output terminal of the bridge rectifier?
If there is then follow it until it stops and you will find the problem. It looks like it goes through two connectors which might be loose.
Ok guys I have traced out the schematic and found that R401 and R402 are both getting the correct voltage in but are only putting out 3 volts also they are getting hotter than a firecracker. I also found that C101 is popped I even removed it to check it and still no continuity.
So what do you think.
Thank you for all of your help. I replaced the two resistors and the capacitor and the amp works fine now. This was a great learning experience and now I have the knowledge of tracing out this system.