This is proving to be a bit of a challenge.
I checked Q329 and Q330 they appeared fine but I re-soldered them for good measure,
I also cleaned the bias pots and set them to zero (full left turn accessed from the top of the board not the printed underside)
I also cleaned and checked all the ribbon connectors for continuity.
This time the amp powered up fine and played loud and clear on both channels so I let it play for a few minutes and turned up the gain a little.
Still clean audio and then a puff of the magic smoke from R80, the amp continued to play but I cut the power.
IC4 was also hot, IC3 was fine.
I replaced R80 and Q32 from my donor amp and tried again, this time the 10 amp inline fuse blew, the amp powered on without a fuse and played fine but the replacement R80 was beginning to heat up so I cut the power.
So the amp makes clear audio but burns out R80, could IC4 be on the way out??
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I checked Q329 and Q330 they appeared fine but I re-soldered them for good measure,
I also cleaned the bias pots and set them to zero (full left turn accessed from the top of the board not the printed underside)
I also cleaned and checked all the ribbon connectors for continuity.
This time the amp powered up fine and played loud and clear on both channels so I let it play for a few minutes and turned up the gain a little.
Still clean audio and then a puff of the magic smoke from R80, the amp continued to play but I cut the power.
IC4 was also hot, IC3 was fine.
I replaced R80 and Q32 from my donor amp and tried again, this time the 10 amp inline fuse blew, the amp powered on without a fuse and played fine but the replacement R80 was beginning to heat up so I cut the power.
So the amp makes clear audio but burns out R80, could IC4 be on the way out??
I have swapped IC4 for a new one and the amp is powering up fine and working.
The left channel has good clean audio but the right channel sounds weak, and a little distorted.
I also swapped out the large board with a known working amp and it worked fine on both channels so the source of the distortion on the right channel is somewhere on the driver IC board.
Could it possibly be a bad contact in the small relay?
The left channel has good clean audio but the right channel sounds weak, and a little distorted.
I also swapped out the large board with a known working amp and it worked fine on both channels so the source of the distortion on the right channel is somewhere on the driver IC board.
Could it possibly be a bad contact in the small relay?
My first time hearing a larger kenwood amp was in my friend's ranger with a new kac-921 amp running a pair of separate kenwood enclosed 10" sub boxes behind the seat. At the time (late 80s) that was the cleanest system any of my friends had, and I knew a few with huge punch amps and subs and some with alpine, which was also clean. For some reason his system sounded very good. The 1021 you are repairing is their beast back then, I can't imagine how that amp would have sounded. Good luck getting it rolling again
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