DB Drive WDX3K has a nasty turn on pop. And a slight turn off pop. When amp came in, it had shorted outputs, damaged drivers. The gain was full blast and the lpf was all the way down, lol. Not sure if the cranked gain might have damaged something else.. it's running fine aside from the turn on/off pop. is there something I can do to make it fix the problem or make it better? Owner said it did it before the repair... but ya... it's a nasty startup pop.
Attachments
A close diagram is in the repair_tutorial\miscellaneousstuff\sinuslive folder
Q21 in that diagram has failed in some amps.
Generic Class D - Type 4 of the tutorial covers these amps.
Q21 in that diagram has failed in some amps.
Generic Class D - Type 4 of the tutorial covers these amps.
Ok... I replaced Q21... and it still makes pop noise. I have the following readings on Q21. "2T" transistor. base = 12.86v, collector = 0.017v and emitter = 13.08v referenced to the main ground, while amp is playing. Unless it's not the mute transistor. He's on his way to pick it up, says he doesn't care about the thump... I'm just trying to get it better before he gets here, 🙂
I'll have to look over the schematic.
I'll have to look over the schematic.
OK, so pin 3 of the output card has nothing at first... when I add remote, it climbs to about 0.03v for a couple seconds, then goes to ground.
That's the problem. If you see this again, determine why the voltage isn't going from 12v to ground. The circuit is fairly simple. The equivalent of Q21 (if the circuit isn't identical) pulls high and then turns off which allows a resistor to pull the mute pin low and enable audio.
OK, ya, I seen that in the demos. I'm going to try and trace that pin 3 back to somewhere and see if I can figure this out before he gets here. Good thing about SMD stuff, can easily work without needing to remove it from the case. 🙂
Unfortunately this amp is now gone... but he tells me it has been doing this since new. I told him if it ever needs to come back or he gets tired of it, I'll figure it out next time. Thanks again Perry.
Guys, anyone have the schematics for this amp? Mine is also WDX 3k but I installed in reversed polarity and now amp turns on but stuck in protect mode. Please help!
Please don't post in a repair thread that was started by someone else unless you are trying to help them.
Start a new thread if you need help with a repair of your own.
Start a new thread if you need help with a repair of your own.