Zagadka's Site

Had a small win with some Logitec speakers today. They were exhibiting poor volume and distortion. My first guess was caps, they looked sound, but were cheap crappy caps. I re-capped it anyway, with no result. There was also a suspect SOT-23 transistor which drives the power LED, when touched, the distortion changed. I deleted the LED circuit and connected the LED with a resistor direct to the power rail. No love. Then I noticed that touching part of the board near the power switch caused the volume to increase and the distortion improve. I shorted across the power switch and the unit came to life. I didn't even suspect the power switch, it is a sealed self-contained unit which is built into the back of the volume control. So I shorted the switch with a blob of solder (no chance getting a replacement dual gang + switch unit). Now the unit works great. Just with no off =)