AU-222 From the ground up

Mike52787

New Member
About 6 months ago I found a haggard AU-222 at a garage sale for $5, the guy said it wouldn't work anymore. When I got it home I learned why. The fuses had been jumped with wire, and the output transistors were blown. Now I know just enough to be dangerous but not enough to be good about solid state gear, and part of that modicum of knowledge is the fact that if the outputs are blown... probably every other transistor in the unit is as well. So, I stripped it down, removing all the old electrolytics, all the transistors, and any resistors that weren't in spec. Currently it sits in a box waiting for me to get the motivation and disposable income to fully rebuild it. Any tips on component selection or other things I should know about rebuilding this little beast?
 
Lovely amp highly recomment you replace the adjustment trimmers
Also the transistors on the tone board 2sc871 I used 2sc2240 ksc1845 will also be good these go noisy. If you 222 carbon resistors on the main amp board check the resistance with one leg out of circuit most likely these need changing too they have a 10 percent tolerance but every 222 I’ve had these resistors are in excess of 25 percent out of spec refer to the service manual to find their location I replaced with metal film equivalent with no issue. Good luck with the restoration
 
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