Hi
I have this Lantec PULSE 386 subwoofer I got a while back laying around awating repair for quite some time. Sadly it's missing it's original speakers which it came with.
After plugging in the mains, the LED on the volume controller lights up. When I plug in the 3.5" jack cable to my soundcard (confirmed to work), I get no audio on the subwoofer (nor the speaker jack at the back).
The PCB is quite simple. There is a UTC4558 amp and two D6282 audio amps. When I put my finger on the UTC4558 I can see and hear the speaker "fart". Although, the left side of it (pins 5-8) make louder noise than the right side (pins 1-4) When I go over the D6282 labled 2 with my finger, I can make the speaker fart, albeit quite a bit fainter. When I go over the D6282 labled 1 with my finger, I cannot make the speaker fart (or the noise is so faint that you can barely hear it).
I get continuity across the cables connecting the controller to the subwoofer, so it should be okay. Soldering a jack to the pads connecting the audio in cable (as in bypassing the entire audio cables) doesn't work.
A 10k resistor near the D6282 labled 1 had a melted outer casing (might or might not be a manufacturing defect), but it read within spec (10.12K). For sanity I replaced it with a brand new 10k.
Currently I'm injecting 16V at the main filter cap since I don't wanna poke around a device connected to mains.
I'm thinking this is either a dead audio amp or bad caps, but since this is my first time with fixing audio appliances, I'd like to ask for guidance. After I opened it for the first time I noticed the bass potentiometer had been reflowed before me. Everything else looked factory.
I have this Lantec PULSE 386 subwoofer I got a while back laying around awating repair for quite some time. Sadly it's missing it's original speakers which it came with.
After plugging in the mains, the LED on the volume controller lights up. When I plug in the 3.5" jack cable to my soundcard (confirmed to work), I get no audio on the subwoofer (nor the speaker jack at the back).
The PCB is quite simple. There is a UTC4558 amp and two D6282 audio amps. When I put my finger on the UTC4558 I can see and hear the speaker "fart". Although, the left side of it (pins 5-8) make louder noise than the right side (pins 1-4) When I go over the D6282 labled 2 with my finger, I can make the speaker fart, albeit quite a bit fainter. When I go over the D6282 labled 1 with my finger, I cannot make the speaker fart (or the noise is so faint that you can barely hear it).
I get continuity across the cables connecting the controller to the subwoofer, so it should be okay. Soldering a jack to the pads connecting the audio in cable (as in bypassing the entire audio cables) doesn't work.
A 10k resistor near the D6282 labled 1 had a melted outer casing (might or might not be a manufacturing defect), but it read within spec (10.12K). For sanity I replaced it with a brand new 10k.
Currently I'm injecting 16V at the main filter cap since I don't wanna poke around a device connected to mains.
I'm thinking this is either a dead audio amp or bad caps, but since this is my first time with fixing audio appliances, I'd like to ask for guidance. After I opened it for the first time I noticed the bass potentiometer had been reflowed before me. Everything else looked factory.
Attached Files
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