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I rarely give trade secrets on an open forum but after recent events I will share a high tech experience. One of the the systems I updated  with powered speakers etc  replaced a Mackie 808 powered mixer which is one of the best ever made..  His daughter did a gig last weekend and it cut out faded and popped on both channels. Lanny called and said we desperately need this fri.

I have had maybe 3 808's apart but from those experiences knew that all the parts were generic. And 90 % of the time when both channels are broke it's the power supply. It was intermittent which sometimes can be a (@$%&#!)..The mixer brd on the front can be removed with a few screws.  When testing I flexed the plug on the amp from the mixer brd and it cut out , No prob!!!  However to remove the amp from the heat sink requires removing screws from about 50 outputs and voltage regulators.  After resoldering the connections on the plug it worked again

 Lanny called the next day and said it is doing the same thing only now it is popping. I said well let's do it right and replace the filters...

Following is for the tech types but is good info for all..  The power supply takes (4) 15000 uf @ 50 vdc. I have never seen a ckt brd with ground traces on the component side of the brd so when soldering in a little 40 watt soldering iron wont suffice .. Use a 125 watt soldering gun and pour the solder to it to make connectiion on the opposite side.. In fact I think if I would have done this at first it prob would have solved problem the  but I believe in downsteam maintenence.  (electrolytics tend to dry out with nonuse) It is good for 5 more years now...    

All the output transistors on this amp are replacable with generics and for those considering an estimate to repair I hope this provides some enlightenment....

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