Repair snapped USB flash drive

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I have a USB Flash Drive that has had the USB connector snapped away from the circuit board. In the past I have had great sucess with soldering the connector back to the circuit board with 4 solid core wires.

Unfortunately this particular device shows up as "Unknown Device" in device manager and displays 0ma power usage. Giving a closer look at the circuit board it appears that the Data + connector has come away from the PCB. Which would explain why it is not recognised.

Is there any practicable way of lifting the data from the device?

larger version

Richard Slater

Posted 2009-12-15T14:39:38.730

Reputation: 576

Is there any way you can take a zoomed in picture of the device? – xxl3ww – 2009-12-15T14:46:34.333

4"In the past I have had great success with..." Uh... how many USB flash drives have you broken in this way? Have you considered that maybe you should be gentler with these things? ;) – retracile – 2009-12-15T14:56:36.550

heh, I am an IT technician in a large school. Added a slightly blury picture. – Richard Slater – 2009-12-15T15:26:16.010

Answers

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My answer assumes you soldered your wires directly to the PCB (somewhere after the plug). The hope is that if you solder wires farther back (at the ESD clamps, if they exist), then you'll have better results.

Using the plug pinout provided by Wikipedia (the 'plug' is usually on the device, and the 'receptacle' is on the board accepting your device), I would open your device and follow the connector's data pair back on the PCB.

The traces should lead to a four-pin or six-pin clamping device(s), devices usually used to prevent ESD spikes from getting onto the PCB. Chances are the PCB broke at the plug connector, which means the traces at the clamp device are still 'good'. If you can see the data pairs make a physical connection to the clamp chip(s), you should be able to solder twisted wires from it to a receptacle connection on an extender cord (receptacle <-> plug). Make sure they are twisted to mimic differential routing on your PCB.

Now, you just need power and ground connections. I suspect the ground and power pins on your broken plug are still good, so wire them directly from your broken plug to the cable.

With this complete, you've just replaced the plug. If you've soldered the connections correctly, and the traces are good (if the data pairs were broken at the plug, not the clamp), you should be able to plug your receptacle <-> plug cable into a laptop or PC to retrieve your data.

Good luck!

ralford

Posted 2009-12-15T14:39:38.730

Reputation: 185

Right... out of my depth now. As he has quite a bit on there he is going to try a data recovery company, out of interest can you highlight the ESD clamps from my image? – Richard Slater – 2009-12-15T15:29:10.137

1See the two middle pins on your connector? They are the data pair. Following those traces back (as much as I can see... the image is a little fuzzy), they go back to a component that is not populated on the board (designed 'L1'). This region was probably intended for a ferrite bead. I would solder to the two pins of this that are further back.

There may be a clamp further back in the circuit (between 'L1' and the controller), but I can't make one out in the image. – ralford – 2009-12-15T15:43:42.713

The owner of the device decided it wasn't worth the £100 to get it done properly. We tried following the tracks back (using a probe) eventually to the IC you can see in the circuit above got Windows to recognize the USB device was plugged in however not what it was or get any data out. Thanks for your help. – Richard Slater – 2009-12-16T11:37:04.363