JBL PSW-D110 Help!

[thedancingman4321]

I recently bought this powered sub at a yardsale for my own uses. The subwoofer will not turn on. Opened it up, there was no fuse. Bought a replacement, put it in, and tried to fire it up. The fuse nearly instantaneously blew, leaving me wondering if this could be fixed. There is a wire on the power supply block that is unconnected to anything and I am wondering if this has anything to do with this. See pictures. Thanks!

Note, the forth pic is the reverse of where the burn mark is.

 

[CocaCola]

Based on the burn marks seen in the third picture, I would investigate the resistors in that area, the two medium sized gray ones would be the first ones to test, it might be as simple as heating their solder joints up, or they might be faulty...

 

[thedancingman4321]

I looked into it and the resistors look alright, but the largest of the three might be damaged. I followed the burn trail, and it looks like the amp section might be blown...

 

[CocaCola]

I looked into it and the resistors look alright, but the largest of the three might be damaged

They are easy to test...

 

[thedancingman4321]

I meant that when I tested it the resistance was about a quarter of it's rated resistance

 

[(*steve*)]

Did you test it in-circuit, or did you unsolder one end first?

Measuring a resistor (or anything) in-circuit will often give you lower results than you might expect because of other components that are also connected.

 

[thedancingman4321]

In-circuit. This only strengthens my belief that the amp section of the amp has died .

 

[(*steve*)]

In-circuit. This only strengthens my belief that the amp section of the amp has died .

Why? I see no evidence for that yet.

It may be true, but you really haven't tested anything yet.

One obvious issue is whether it is getting power or not. The power supply may be the issue.

 

[Comnics]

check the resistor and also the zener diode and signal diode.