Hi there,
New to the forum and hoping someone can help.
I salvaged a Rotel RA931 MkII off the side of the road only to find the right channel is dead. Thought it might be the fuses so changed them out but no luck. This was not going to be a quick fix.
So I did some testing:
- R channel out on both direct and remote speakers
- headphones OK on both channels
- visually inspected all components for damage/burnout/bulging caps etc. - no issues found
- started tested some components with my multimeter and found R634 is dead
So before I remove the circuit board to check the underside for cracked solder and attempting to replace R634... am I on the right track and is it worth it?!
Thanks in advance for any help!
New to the forum and hoping someone can help.
I salvaged a Rotel RA931 MkII off the side of the road only to find the right channel is dead. Thought it might be the fuses so changed them out but no luck. This was not going to be a quick fix.
So I did some testing:
- R channel out on both direct and remote speakers
- headphones OK on both channels
- visually inspected all components for damage/burnout/bulging caps etc. - no issues found
- started tested some components with my multimeter and found R634 is dead
So before I remove the circuit board to check the underside for cracked solder and attempting to replace R634... am I on the right track and is it worth it?!
Thanks in advance for any help!
r634 = 33k? check what you have as voltage in hamont of this resistance (normally a few mV to tens of mV) if you have +, it means that you have a problem on the circuit.
https://audio-circuit.dk/downloads/rotel1/Rotel-RA931_MKII-int-sm.pdf
https://audio-circuit.dk/downloads/rotel1/Rotel-RA931_MKII-int-sm.pdf
Thanks for the quick reply. Yep the R634 is a 33k resistor. I powered it up and read about 0.3V DC across the resistor.
Downstream (toward the speaker outputs) it is 0.2 - 0.3V.
Upstream (into the rest of the circuit board) I tested in a few places and it is around 4mV.
Hope this helps, sorry if it is not clear.
Upstream (into the rest of the circuit board) I tested in a few places and it is around 4mV.
Hope this helps, sorry if it is not clear.
33k seems to be the resistance of feedback, try to put a new one and above all, when you put the amplifier back on, you don't need a speaker connected to the output.
I would be surprised if your amp works without more damage but you have to try to find out (keep your finger on the power button when it smokes and if you do not have a circuit with a safety bulb )
I would be surprised if your amp works without more damage but you have to try to find out (keep your finger on the power button when it smokes and if you do not have a circuit with a safety bulb )