Hi
This amp had several problems starting from power supply and preamp section. I cleared most of the problems. Now amp coming on and preamp sending clean signal to the output section but after this no output on any channel. Anybody know if it have any mute circuit in this amp please let me know. Thank you.
Attaching the picture.
This amp had several problems starting from power supply and preamp section. I cleared most of the problems. Now amp coming on and preamp sending clean signal to the output section but after this no output on any channel. Anybody know if it have any mute circuit in this amp please let me know. Thank you.
Attaching the picture.
Attachments
I can't tell if this is the type of fixative that turns dark and then becomes both conductive and corrosive but if it is, it has to be removed.
This board appears to be a cheap CEM board with no VIAs. If so, all points that have solder on both the top and bottom of the board are suspect and will likely fail. It's a lot of work to repair them properly.
If this amp uses NPN transistors for muting (not the JFETs that PP originially used) it's an Asian design. I may be able to find something similar but I'd need very high resolution images of both the top and bottom of the board showing the area around the PS control circuit.
This board appears to be a cheap CEM board with no VIAs. If so, all points that have solder on both the top and bottom of the board are suspect and will likely fail. It's a lot of work to repair them properly.
If this amp uses NPN transistors for muting (not the JFETs that PP originially used) it's an Asian design. I may be able to find something similar but I'd need very high resolution images of both the top and bottom of the board showing the area around the PS control circuit.
Yes this is that kind of fixative. I removedthe black most of the places where two parts are touching.
Sending the pictures to your email.
The fixative can eat through components (bodies of resistors, component legs) and cause all sorts of problems.
See if the circuit around U3 in the diagram is similar to the circuit around the optocoupler in your amp. Don't expect all values to be the same.
If they are similar, the equivalent of C601 sometimes becomes leaky and prevents it from charging.
See if the circuit around U3 in the diagram is similar to the circuit around the optocoupler in your amp. Don't expect all values to be the same.
If they are similar, the equivalent of C601 sometimes becomes leaky and prevents it from charging.
It look very similar on the diode side of the optocoupler. The 220uf capacitor was good but I still changed it. Still no output. I tried to short diode side of optocoupler nothing happened. Is there a way i can bypass mute just to check how output is?
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