MobileRead Forums - View Single Post - PRS-650 PRS-650 micro-USB slot is loose

delphin · 06-14-2011, 07:23 AM

My PRS-650 micro-usb connector also shows a little bit of play - a little more with some micro-usb cables - a little less with others.

The play is tiny, only about a fraction of a millimeter, and a few degrees of travel at the connector itself, but this is enough that it feels just every so slightly like something is 'loose', and this feeling gets magnified by distance, so you can actually wiggle the end of the micro usb plug back and forth about 3 or 4 mm (say 3/16 inch).

So if this is what you are seeing, I wouldn't worry about it, because it seems to be normal for Micro-USB.

Micro-USB requires very precise alignment, because the electrical contacts are so small, so this may seem strange . . .

You would think that with such small electrical contacts, we would need to make the tolerances extremely tight and lock things down so tightly that they can't budge even the tiniest bit.

But beyond a certain point this just isn't practical, so an alternative is to design the connector so that the critical parts, the electrical contacts, float slightly and self align when mated, and then make sure that the other parts of the connector have enough play so that they won't knock the contacts back out of alignment during normal handling

This can give the the micro-usb connector the feeling of just a little looseness, but this is designed in, and perfectly normal.

So, as a practical matter on your PRS-650, if wigging the cable gently back and forth through it's normal few mm of travel doesn't cause data errors, or device disconnect issues, I wouldn't worry about it.

06-14-2011, 07:23 AM	#4
delphin Evangelist Posts: 434 Karma: 346901 Join Date: Dec 2010 Device: SONY PRS-650	My PRS-650 micro-usb connector also shows a little bit of play - a little more with some micro-usb cables - a little less with others. The play is tiny, only about a fraction of a millimeter, and a few degrees of travel at the connector itself, but this is enough that it feels just every so slightly like something is 'loose', and this feeling gets magnified by distance, so you can actually wiggle the end of the micro usb plug back and forth about 3 or 4 mm (say 3/16 inch). So if this is what you are seeing, I wouldn't worry about it, because it seems to be normal for Micro-USB. Micro-USB requires very precise alignment, because the electrical contacts are so small, so this may seem strange . . . You would think that with such small electrical contacts, we would need to make the tolerances extremely tight and lock things down so tightly that they can't budge even the tiniest bit. But beyond a certain point this just isn't practical, so an alternative is to design the connector so that the critical parts, the electrical contacts, float slightly and self align when mated, and then make sure that the other parts of the connector have enough play so that they won't knock the contacts back out of alignment during normal handling This can give the the micro-usb connector the feeling of just a little looseness, but this is designed in, and perfectly normal. So, as a practical matter on your PRS-650, if wigging the cable gently back and forth through it's normal few mm of travel doesn't cause data errors, or device disconnect issues, I wouldn't worry about it. Last edited by delphin; 06-14-2011 at 08:48 AM.