Jim/Fairchild's old Yamaha MX-800U - Five years later out of the box!

jbeckva

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#1
So as I am sitting around waiting for the next WOPL build comin' (should be soon here I think), I got bored. Went into the other room and pulled out a dusty old shipping box that Mr. Jim had sent me this MX-800U for free back in (wait for it.. ) 2013. Much appreciated, Jim.. even over 5 years later LOL anywhoo...

Unpacked and assessed. Nothing blew up or gave any indication of a current OL while putting it on the variac, but yeah.. it has issues. No display and as you can see the protection light is well lit, plus a foot missing.

Time to open 'er up and see what's what. Might have a good amp for the other room when I get done here. Not holding my breath too much tho, since a lot of the parts in these guys are obsolete and unobtanium.

1-Assessment.jpg
 

jbeckva

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#3
LOL thanks Lee! I guess I just fixed the meters. Was the classic "meter switch in the O F F position" issue... haha! Well, onward to figuring out what's up with the protection light. No fuses blown so that at least is a good thing.

meterfixedLOL.jpg
 

WOPL Sniffer

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#4
Those are great amps. My buddy has been pounding on hes for years. I tried to con him out of it a while back. They go for a pretty penny....
 

jbeckva

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#5
Perry I had a M-80 awhile back too. That one grew "nads" (search for it LOL)..

Well, found the prob, at least part of it as who knows what else got it in the process.

Couple of smoked resistors, and the tranny that did it. Wondering if ebay is to be trusted on the 2SA1306's as that's the tranny I need so far.

3-smoked.jpg

4-smoked2.jpg
 

orange

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#6
LOL thanks Lee! I guess I just fixed the meters. Was the classic "meter switch in the O F F position" issue... haha! Well, onward to figuring out what's up with the protection light. No fuses blown so that at least is a good thing.

View attachment 33215
 

orange

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#7
I'm sure it will be able to play the violin again.
 
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