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Hi everyone,
I have had this amp sitting around that someone gave me and got the urge to take a crack at fixing it with my newfound soldering skills. You can turn it on and the red light comes on, but no sound whatsoever. I found a couple of obvious issues show in the pics below. Using the schematic I found in another thread I have identified a few things. A resistor R48 is missing with a scorch mark where it was. The air choke L1 also is scorched. The transitor VR2 had a chunk missing and the VR1 transistor has some discoloration (highly exaggerated by the flash in the picture, but causing the top line of text to be illegible).
I have done some minor circuit board repair, but I am a total noob to amp repair. It would be easy enough to replace the missing bits and see what happens, but I suspect there may be some upstream stuff that I need to check as the resistor that is blown off the board is right in the output. Any input would be appreciated. Suggestions on where to get the components/ part numbers, especially the transistors would be swell.
FWIW, the speaker passes the 9V battery test. I don't know if this is important, but the wiring to the speaker looks less than professional. It looks like stranded lamp cord soldered to the outputs, wire tied to some 16ga that had been cut and twisted back together at some time.
https://picasaweb.google.com/lh/phot...eat=directlink
https://picasaweb.google.com/lh/phot...eat=directlink
I have had this amp sitting around that someone gave me and got the urge to take a crack at fixing it with my newfound soldering skills. You can turn it on and the red light comes on, but no sound whatsoever. I found a couple of obvious issues show in the pics below. Using the schematic I found in another thread I have identified a few things. A resistor R48 is missing with a scorch mark where it was. The air choke L1 also is scorched. The transitor VR2 had a chunk missing and the VR1 transistor has some discoloration (highly exaggerated by the flash in the picture, but causing the top line of text to be illegible).
I have done some minor circuit board repair, but I am a total noob to amp repair. It would be easy enough to replace the missing bits and see what happens, but I suspect there may be some upstream stuff that I need to check as the resistor that is blown off the board is right in the output. Any input would be appreciated. Suggestions on where to get the components/ part numbers, especially the transistors would be swell.
FWIW, the speaker passes the 9V battery test. I don't know if this is important, but the wiring to the speaker looks less than professional. It looks like stranded lamp cord soldered to the outputs, wire tied to some 16ga that had been cut and twisted back together at some time.
https://picasaweb.google.com/lh/phot...eat=directlink
https://picasaweb.google.com/lh/phot...eat=directlink
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