Troubleshooting the dB Technologies Basic 200 Active Speaker

[corebots]

hello, I'm new here. Thank you for making such a great forum and source of information. I'd like to ask you for help:

Our dB Technologies Basic 200 Active Speaker stopped working without any indication of what's going on. I've made some pictures of the components. From what I can see the board looks vine doesn't it? The cone of the speaker however is torn - how could this happen? overload? It was only used for vocals in our rehearsal room... Wouldn't the speaker give at least some sound if the problem was only the cone?

Could anybody have a look at the pictures and give me a hint?

http://i.imgur.com/7HdhILz.jpg
http://i.imgur.com/Cve3eAM.jpg
http://i.imgur.com/diyUb3E.jpg0
http://i.imgur.com/PO0uuHb.jpg
http://i.imgur.com/voUCf6q.jpg
http://i.imgur.com/pSAV7La.jpg

 

[corebots]

do you see something damaged on the board?

 

[Enzo]

It is important to do a visual inspection of any amp, just to find quickly any major damage. But MOST bad parts do not look any different. So it is usually the case that nothing appears damaged.

I have no idea how your speaker cone was torn, however, it will never sound good even if it works. That speaker needs to be replaced or reconed.

Take the wires off the speaker, and test the speaker with a 9v battery. Then you will know if that is the only reason for the silence.

To test the electronics, connect the amp circuit to some other speaker. But before you do that, measure for DC voltage on the speaker wires. You don;t want to hook up a speaker if there is substantial DC voltage across it.

 

[corebots]

- I've tested the speaker with a 9V battery and could hear a little of quiet cracking when connecting the wires
- tried to measure on the speaker outputs but couldn't measure anything - nor A nor V (with no input connected)

Thanks for the instructions, I'll have to find another speaker to test the electronics.

Would there be any easy measure points on the board to check if it is still ok?

 

[dotneck335]

Those pictures don't convey a lot of information. Have you been able to locate a schematic? That is a MUST. A good starting point is to measure the power supply.