This is a Bose AWRC1G Wave Radio CD. The unit had a slight hum in the background after a power outage then went to a loud buzz shortly thereafter. My initial thought was that it was just a cap but in this case the problem turned out to be more.
Initially I found the 2SA608 transistor at Q206 bad. I replaced it with a NTE290A only to have it immediately start heating up. The input on the 10V regulator was low (as was the output) and there was excessive Vpp sawtooth. This indicated to me there was an excessive load on the 10V circuit somewhere. I traced out the 10V circuit and found a TDA7313ND IC at U605 running considerably hotter than any other IC. This IC is primarily used as a digital volume control. I think it does the input switching as well. I pulled the IC and the 10V returned to normal with no excessive heat. Replacing the IC and transistor resolved the issue.
Негізгі бет Bose Wave Radio CD Model AWRC1G loud buzz through speakers
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