Hello All,
I just acquired a Parasound HCA-1500A with an almost dead left channel, as volume was barely perceptible. After taking things apart, I found 2 issues: two blown fuses on the main board, and a cold solder joint on the stereo-bridge switch. The left channel came to life, but runs warmer than the right channel. I'm attempting to adjust the bias, and need your help to identify the emitter transistors correctly. On the schematic, I highlighted the trim pot TVR101, so am I correct to assume that a measurement should be taken across R130 and R127? Parasound's recommendation for the bias voltage for this amp is 15 mV, +/-2 mV. I built Rod Elliott's P101 so I am somewhat familiar with bias setting (not a pro by any means).
Thanks in advance for your guidance.
Hong
I just acquired a Parasound HCA-1500A with an almost dead left channel, as volume was barely perceptible. After taking things apart, I found 2 issues: two blown fuses on the main board, and a cold solder joint on the stereo-bridge switch. The left channel came to life, but runs warmer than the right channel. I'm attempting to adjust the bias, and need your help to identify the emitter transistors correctly. On the schematic, I highlighted the trim pot TVR101, so am I correct to assume that a measurement should be taken across R130 and R127? Parasound's recommendation for the bias voltage for this amp is 15 mV, +/-2 mV. I built Rod Elliott's P101 so I am somewhat familiar with bias setting (not a pro by any means).
Thanks in advance for your guidance.
Hong