Addition Bose Amp Fix

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EVERYTHING IN THE OTHER BOSE AMP FIX IS CORRECT INFO, BUT EVERYBODY THINKS
IT\’S ONLY THE TWO 820UF CAPS THAT GO BAD BECAUSE THEY ARE THE BIGGEST
ONES ON THE BOARD. IN REALITY THERE ARE SEVERAL ELECTROLIC CAPACITORS THAT
CAN GO BAD ON THESE CARDS. AS ON ALL ELECTRONIC EQUIPTMENT ELECTROLIC CAPS
TEND TO DRY OUT OVER TIME AND NEED TO BE REPLACED. THERE ARE TWO
47UF,THREE 10UF,AND ONE 4.7UF SMALLER CAPS IN THE SAME VICINITY AS THE TWO
820UF THAT ARE ALSO POSSIBLY BAD IF THE 820UF (1000UF) REPLACEMENT
DOESN\’T WORK. THESE MUST BE THE SAME UF RATING,HIGHER VOLTAGE RATING IS
OK.IT MAY ONLY BE ONE OF THEM BAD BUT I SUGGEST YOU REPLACE THEM ALL,THEY
ARE CHEEP TO BUY. ANOTHER POSSIBLE(LESS LIKELY) PROBLEM WITH THESE AMPS IS
THERE ARE FOUR IDENTICAL FIELD EFFECT TRANSISTORS ON THE BOARD,ONE OF THAT
COULD BE BAD.THEY CAN BE CHECKED WITH AN OHMMETER. YOU SHOULD ONLY HAVE
CONTINUITY IN ONE DIRECTION BETWEEN PINS 1&2,NONE BETWEEN 1&3AND 2&3 IN
EITHER DIRECTION WITH THE TRANSISTOR REMOVED. IF YOU DO HAVE A BAD ONE
YOUR PROBABLY IN TROUBLE ANYWAY UNLESS YOU HAVE A SPARE BOARD TO ROB ONE
FROM BECAUSE THE TRANS. CAN\’T BE CROSSREFERENCED TO TELL WHAT TYPE OF
FET IT IS. IT WAS MADE JUST FOR BOSE AND THEY DON\’T WANT YOU TO KNOW
WHAT IT IS. AS THE GUY IN THE OTHER FIX TIP SAID, YOU CAN SEE THAT YOU
SHOULD HAVE SOMEWHAT OF AN ABILITY TO SOLDER AND A BIT OF ELECTRONIC
KNOWLEDGE OR YOUR PROBABLY BETTER OFF GETTING A NEW AMP OR HAVE YOURS SENT
OUT FOR REPAIR. WELL THAT\’S ALL I HAVE,GOOD LUCK! LOWGLIDER


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