My time to suffer the rear speaker Bose Amplifier failure came recently.
The symptoms were a shhhh sound when the volume was at the minimum, reduced speaker output at listening volume, intermittent output and distorted sound.
I got myself in the trunk and with a medium philips screw driver removed the 3 screws that hold the amplifier cover to the speaker/amplifier housing. Then pulled the white connector from the circuit board and by removing the 2 philips screws inside, the board was free in my hand.
I removed the heat sink / EMI shield by pulling it from the terminals that hold it to the circuit board.
Upon inspection, I found that most of the electrolytic capacitors (small cylinder looking components) were fouled and decided to replace them all.
I used a soldering iron, rosin core solder and soldering paste to replace the capacitors.
I made sure that I respected the polarity of the capacitors, they have markings on the outside (typically a (-) sign and an arrow). I installed the new capacitors with the markings in the same direction as the ones I removed.
The specs of the capacitors and their prices from Digikey (800-344-4539 or digikey.com) for each rear amplifier are:
Cap. Specs Qty Dimensions(mm) Digikey Part No. Price ea. Total
105 deg F dia. x height1uF,50V 2 4 x 7 P931-ND .30 .60
10uF,16V 3 4 x 7 P910-ND .32 .96 47uF,16V 2 7 x 7 P914-ND .40 .80 820uF,16V 2 12.5 x 15 P10252-ND 1.13 2.26uF = microfarads V = Volts
Digikey has a handling fee of $5.00 per orders less than $25.
The total in parts to replace the capacitors in both rear amplifiers is $9.24 + 5.00 + shipping.
After the replacement, I was delighted once more with the sound quality.