Find the end of R27 that connects to the striped end of D6. Does the voltage on that end of R27 follow the voltage on pin 7 of IC2?
Do you see the same voltage on the other end of R27?
Do you see the same voltage on the other end of R27?
Hi, realised what you mean, the component numbers on the board?
r27 is not on the board, it is marked out but nothing is in the space
r27 is not on the board, it is marked out but nothing is in the space
That resistor connects the muting opto-coupler to the mute drive circuit. Without it, the muting circuit can't work properly.
I doubt that they would have installed a relatively expensive opto-coupler if they were going to defeat the protection circuit. MANY amps have manufacturing defects. This 'may' be one.
Is it definitely a 3.9k ohm needed? is this the right one:
3.3K to 9.1KMetal Film 0.6W Resistors : Metal Film : Maplin
3.3K to 9.1KMetal Film 0.6W Resistors : Metal Film : Maplin
That would work. Isn't there a local electronics distributor where you could buy a resistor without having to order it?
What's the voltage on each side of the resistor?
What's the voltage on the opto-coupler now that you've installed the resistor? Post the initial voltage as well as the voltage after the mute delay, as you did previously.
What's the voltage on the opto-coupler now that you've installed the resistor? Post the initial voltage as well as the voltage after the mute delay, as you did previously.
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