Yamaha A-760 II - leaky caps

[Wirehead]

Just a heads-up for any A760 II owners. The caps that are in the biasing circuit develop leaks. (2 pairs on each side of the board - 100uF) I had one in for servicing and it caused corrosion to the traces on the bottom. Had to recreate the traces.

Also, the glue used to keep the big Elna 15.000 uF caps steady while wave soldering, is probably acidic. It caused a jumper wire to have a bad solder connection (corroded).

There's also 2 smaller Elna (220uF/63V) in the middle that are prone to leaking. Next to it is another cap that needs preventive maintenance: it's constantly being boiled by the power resistors next to it.

Oh yes - and get rid of the RIFA PIO caps in all cases. They go out with a bang

I've attached a pic with the locations of the caps. It's better to change them sooner than later. Fixing corroded PCB traces is no fun

 

[OMGCat!]

That bonding glue is used in a bunch of our amps (some Sansuis and Sonys too) and loves to cause a mess after a good few decades. I've never had one gone to the point of chewing through jumpers or solder connections but have always found at least some damage to components/jumpers that were in contact with the glue.
I'm not sure if it's acidic or if it just holds moisture close to things that would prefer not to be moist. Either way, the sooner it's out the better and the more likely the magic smoke stays where it belongs.