Rotel RA-971 MkII Capacitor leak? Fuse blow


2020-01-26 12:26 pm
Hi all. I recently purchased a Rotel RA-971 MkII. It powered up OK. I power down, plugged some 4ohm speaks and a streaming source in Aux1, turned volume down and powered up, bought the volume up and both 6.3A fuses in the power circuit (just after the transfo) blew.

Opening up the case I noticed a. the blow fuses but also b. 4 capacitors with a brown crispy gunk at the base.

Have these caps leaked there electrolyte? Or is that old glue? There are a load of other caps on the board that don't have this brown substance at the base.
When I touch it with a screw driver it cracks and comes away from the circuit board easily in small pieces.
Could these caps be source of the fuse blow? Any thoughts most appreciated.


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The black stuff is just mounting glue. It's probably best removed as it could be corrosive, but is not likely to be the reason for your fuse fireworks.

I suggest checking the output transistors for shorts, as well as the big reservoir cpacitors and rectifier. If nothing found, replace fuses, power up without speakers and measure DC offset on both outputs.