Intro (Howdy) and Me Yammy M-80

[jbeckva]

Hi All,

Been in lurk mode for a bit, so I figured I'd introduce myself when I had a good project ahead of me. Been into hi-fi since I was 3 years old (stealing the old man's Sansui / Garrard stereo and getting my butt beat), got away from it for a good while until about a year and a half ago. I did 10 years Navy as an Avionics Tech ... worked on just about every fixed-wing aircraft from P3 to F18. Nice skill to have when working on old vintage stereo stuff.

Anyway... I finally got my hands on something I had drooled over during the mid/late 80's before the Nav stole me away... Yamaha M-80 amp. Sounds great so far.

I did have a BIG scare however when I first set it up. I set it up and listened for a bit before heading off to dinner. No problems.

Came back about 2 hours later. Hit the power switch ... and (YIKES) the 10A main fuse blew! My first impression was "ah <bleep!>", but after further review I did notice the voltage selector was set to 110v, whereas the US is 120v. I also noticed a spare next to the one blown, so I figured what the hey.. didn't have much to lose so I reset the voltage to 120v and replaced the fuse.

That's been about 24 hours... no problems since, but seriously... Is the M80 that finicky? Maybe it was the voltage.. maybe an intermittent varistor/cap going bad? In any case, looks like I had better play it safe and gear up for a recap eh? I'm leaning towards the varistor firing off since (a) it was a good "flash" and (b) there was no downstream collateral damage (even the fuses on the secondary side of the transformers are still intact). But still... better safe than sorry.

I noticed a few Yamaha techs here... for a recap, we're talking at least the 4 big ones near the rear, right? What about the 2 on the main pcb? Also - any good sourcing info for these caps? (33k/56VDC X 2 and 47k/45VDC X 2 for the mains and 1k/100VDC x 2 for the two on the PCB)

Thanks and again, great to be here! Seems a lot of good info being traded back and forth, so I hope to contribute some myself where I can.

[Jan Dupont]

It shouldn't be that sensitive, however I'm not an Yamaha expert.....
Maybe this can help;
http://www.audio-circuit.dk/Schemati...M80-pwr-sm.pdf

[jbeckva]

Originally Posted by Jan Dupont

It shouldn't be that sensitive, however I'm not an Yamaha expert.....
Maybe this can help;
http://www.audio-circuit.dk/Schemati...M80-pwr-sm.pdf

Thanks Jan. I already have the manual tho, but I am probably being a bit "lazy" in hoping there's someone here that has already recapped an M-80 and knows a good p/n or source for the caps (or at least the dimensions... hate to have to take it apart before the parts are on order). Has to be someone that's done this one before, eh??

But oddly enough, it's been about a week now and I haven't seen a reprise of the weird fuse incident. If anything, the amp's been 100 percent solid. Got a hold of a 2nd pair of speakers today (Infinity Reference Six's), and even with them and the Polk SDA's in parallel, the amp's hardly breaking a sweat.

(Hmmm.. should I or shouldn't I?? )