Originally Posted by Bengt

Nokia N900 repaired!

Hi all! My daughter had this problem with her Nokia N900. The USB connector got loose and she couldn't charge it. As usual I disassembled the phone (it was surprisingly easy, at thought such a phone should be complicated to disassemble!) and soon I could see the problem. The USB connector have loosened from its pads. I tried to solder it down again but I realized that the copper foil have loosened from the laminate at the small pads under the connector so it didn't help. They were also impossible to investigate without desolder the entire connector. Trying to do so I found it extremely difficult to solder. All heat just flooded away into the copper planes. At that point I started Googling and found this forum. Very interesting but no solutions!

What is the problem? Regardless what some have said the reason to that the connector is getting loose is a bad design of the pads. The designer have put tens of laser vias into each pad and that leads away all the heat down to the planes. Especially one side of the connector have bad soldering. The very close shield box is another reason. So this design made it impossible to get a through soldering of the connector during the manufacturing.

Repair? I desoldered the remaining parts, it was so difficult that I ended up cutting it to pieces. Now I could see that the small pads inside the connector was directly connected to inner layers through laser vias. Impossible to solder again. There was a little crater in each of the pads down to inner layers. Therefore the only solution would be to put cables from the connector to somewhere on the board IF I could find such a place. I managed to dig down into the laser vias using a sharp tweezer and could start searching with the multimeter.

YES, there are test pads for the entire USB connector elsewhere on the board. So, I bought a new connector, soldered very small cables to it and connected them to test pads. (Using a high end professional soldering station). I covered some of the broken pads with isolation paint because underlaying conductors have been freed. Just to make sure nothing got short cut. I used another, very high power soldering iron to solder the new connector. This time, with more power, it worked. One pin in the corner of the shield box was impossible to solder so I soldered it directly to the shield box instead!.

Tested it and it worked perfectly!

I have uploaded two images. One of the free pads and one of the repair. You can see the pads on the mother board that i used. For GND I used the original pads after putting a small wire from the pin to the connector case.

Originally Posted by geneven

I don't know, but it superficially seems to me that you don't have a real problem at all. Just get an external charger and use it to charge batteries. It is cheap and better and easier than charging by connecting your N900 anyway.

Originally Posted by redhotfoo

I am driving a lot and therefore need Sygic Mobile Maps, which dramatically reduces battery life. Carrying a second battery is unpractical. My phone can charge battery via USB Data Connection, but refuses to load from usual wall or car charger. Now is there a way to cheat on my phone and "emulate" a USB Data connection? Or is there a better solution?

Still hoping to find some answers...

Originally Posted by Rob1n

The micro USB charging standard requires the data pins to be shorted. Unfortunately most 3rd party chargers don't do this, so the N900 won't charge with them. You may be able to open them up and short out the data pins (the middle two) or, if they're using a separate USB-microUSB cable, modify a cable to short those two lines out.