About 3 years ago I bought a 2.1 speaker system for the TV in my computer room. It was rated at 150W or 75W depending where you looked (what a bunch of lies). Inside it had a small 9VAC/1.1A power transformer (9.9W).
Its real total output is about 5.5W to 7W. It sounded great for two years then its woofer became intermittent.
When its speaker connector was wiggled on the pcb then the woofer sound came and went. So I removed the connector and soldered the woofer wires directly to the pcb and it worked fine for a couple of weeks. FIXED! But no, it became intermittent again. Maybe its power amplifier IC shuts down when it gets heated? Maybe the tone controls connector has an intermittent contact?
I looked and looked but saw nothing wrong. The soldering on the pcb looked good. The woofer stopped and started if the pcb was flexed one micron or more.
Today I re-soldered every solder joint on the pcb and now I cannot make it stop working.
Its real total output is about 5.5W to 7W. It sounded great for two years then its woofer became intermittent.
When its speaker connector was wiggled on the pcb then the woofer sound came and went. So I removed the connector and soldered the woofer wires directly to the pcb and it worked fine for a couple of weeks. FIXED! But no, it became intermittent again. Maybe its power amplifier IC shuts down when it gets heated? Maybe the tone controls connector has an intermittent contact?
I looked and looked but saw nothing wrong. The soldering on the pcb looked good. The woofer stopped and started if the pcb was flexed one micron or more.
Today I re-soldered every solder joint on the pcb and now I cannot make it stop working.