A funny thing happened, leaving me perplexed.

A week or so ago a pair of usb powered + 3.5mm jack speakers stopped working.

On removing the backs I saw that one of the leads connecting to one speaker itself had come off so this morning I soldered it back on.

After testing the speakers on an older laptop where they now worked I returned the speakers to their original laptop where they also worked again.

This evening the speakers had stopped working again, on firing up that laptop.

 

Yet they started came back to life immediately on plugging them into the older laptop again.

Back to their normal laptop and    --   No joy no workee.

Back to the older test laptop    --   no problemo.

Back to their original   no workee.

 

I am very puzzled.

Another set of the same types works perfectly in either laptop.

Final test the dead? speakers do not display the blue on light when plugged into a usb wall socket supply.

 

Any help welcome.

Is any other info needed ?

 

I would say that it's 100% the usb power connector. USB plugs are a nightmare for working/not working. Sometimes you just move them a tiny amount, and they connect. If the blue light doesn't come on, then the power connection is not being made. 

It's usually the sockets, not the plugs, but in this case it sounds like the plug that's iffey. If you can get at it, try a few strokes of a very fine wirebrush. If you can't it sounds like it needs to be binned, unless you can swap the USB plug for a good one. 

Does the blue light come on with the laptop that it doesn't work with? That would tell you that it's not connecting up the power, either to the wall plug or the laptop, so it points to the usb plug.

20 minutes ago, mistermack said:

I would say that it's 100% the usb power connector. USB plugs are a nightmare for working/not working. Sometimes you just move them a tiny amount, and they connect. If the blue light doesn't come on, then the power connection is not being made. 

It's usually the sockets, not the plugs, but in this case it sounds like the plug that's iffey. If you can get at it, try a few strokes of a very fine wirebrush. If you can't it sounds like it needs to be binned, unless you can swap the USB plug for a good one. 

Does the blue light come on with the laptop that it doesn't work with? That would tell you that it's not connecting up the power, either to the wall plug or the laptop, so it points to the usb plug.

Thanks for the reply, yeah it is beginning to look like a dodgy connection where the lead enters the back of the plug.

 

Disassemble the device until it is in a condition to measure voltages. At multiple different locations on the motherboard. Connect to a working computer. Measure the voltages (record it on a camera (recommended mini tripod) so you don't have to write on a piece of paper). Repeat with a non-functioning computer. This will tell you if and where there are differences.

 

Get "USB Voltage meter":

https://www.amazon.co.uk/s?k=usb+voltage+meter

https://www.google.com/search?q=usb++voltage+meter

The cheapest one is $5

 

*) Get "USB Oscilloscope"

https://www.google.com/search?q=usb+oscilloscope

The cheapest one is $25

 

If you want to play, how about this one DIY?

https://www.google.com/search?q=JYETech+osciloscope+"DSO+138+Mini"

unlike *) it has built-in LCD screen, so you won't have to plug it to the computer, which has advantages and disadvantages.

 

Edited June 25, 20223 yr by Sensei