Home |
Search |
Today's Posts |
#1
Posted to rec.audio.tech
|
|||
|
|||
Troubleshooting Pioneer SX-838 receiver - second posting, mistakescorrected
This is a great piece with one little problem. Often, when switching the
unit on, the left channel is out, no sound. Turning the volume up always kicks it in. Often the volume has to be turned up severely to accomplish this so I tried doing it with the speakers switched off. Switch off speakers, turn volume up to max, turn volume down to min, switch speakers on, turn volume up a bit and the sound is back in both channels. In addition, after getting both channels to work, after 10 to 20 minutes, give or take 5, the left channel goes out again. This behavior lead me to suspect the volume switch, so I flooded it with switch cleaner and worked it, but to no avail. Problem persisted. Next I checked all the cold solder joints and found one that was loose. I hot soldered ALL the cold solder joints. Problem continued. Today I used some cables to switch the PRE OUT channels into the POWER IN channels, left to right and right to left. The next time the problem cropped up it was still in the left channel. This is telling me that the problem is in the left main amp section. Given the behavior described above I can only guess that a rise in voltage in the main amp produced by turning up the volume with the speakers turned off somehow corrects the condition causing this problem, but at the moment I don't know what this condition might be. I assume that with the speakers turned off there is not a lot of current flowing in the main amp when the volume is turned up, but that the voltage is increased. As I write this, a dawning suspicion presents itself and that is: the problem might be with a transistor, as they are voltage regulated. Next step is to open up the unit and do a visual inspection, hook it up to a pair of speakers and turn it on and attempt to compare voltages along the signal path of right and left channels of the main amp when the problem crops up. |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
Troubleshooting Pioneer SX-838 receiver | Tech | |||
Pioneer Stereo Receiver Model SX-939- No audio coming out of the receiver. | High End Audio | |||
OT-Marantz 2216 Receiver Amp Board Schematic/Troubleshooting Advice | Vacuum Tubes | |||
PIONEER SX-780 RECEIVER | Marketplace | |||
Home Stereo Receiver/Amp Troubleshooting Question | Tech |