我的问题
My TV soundbar, an Orbitsound M10LX sounded strange, mostly only bass/woofer sound from it. Voices seemed absent but loud explosions were fine!
我的修理方法
There are no mains voltages present so there are no major safety concerns, the unit works from a DC adaptor. After removing the cover (take out all screws except the ones by the fiber optic input). I could see some areas on the PCB which were corroded. The areas concerned were directly below some 1000uF 35Volt electrolytic capacitors. Over time or with abuse electrolytic capacitors can dry out or leak. The electrolyte in them is corrosive. It can be seen that the copper track has been eaten away in several places. I cleaned the board with a brush and some alcohol in order to see the extent of the damage under the green corrosion layer. Having determined the extent of the damage I replaced the capacitors (there are three 1000uF 35-volt capacitors) with ones of the same characteristics. I soldered links between all the points that needed connecting (the red lines in both positions) checking the joints with a magnifier. After I replaced the cover and reconnected everything I was rewarded by normal sound. I noted that the bass speaker had a slightly different arrangement which prevented corrosion in the same area, I changed the bass coupling capacitor anyway to be safe. So I had been listening to the sound mostly through the bass speaker.
我的建议
A first look at the circuit board is intimidating, so many integrated circuits, and connections everywhere. From my forty-odd years of experience at fault finding, integrated circuits are the least likely to fail unless they are controlling power and getting warm. If you have an unfamiliar PCB to work on then a visual inspection can tell you a lot. If you have a strange fault that makes no sense then check that the voltage rails are okay.
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