Re: Soldering advice needed for re-attaching N900 USB to mainboard.
 

The connection from pin1 (rightmost in this pic) to pin2 which is ID signal, i.e. the red line next to GND label, is incorrect. Pin2 should NOT get connected hard to GND. Though it doesn't do too much of a harm, it might cause conflicts with future versions of e.g h-e-n hostmode-pkg

Rationale: ID (pin2) is meant to detect insertion of A type plugs into (usually) AB-micro-receptacles. It signals to device to act as a USB host. It doesn't work OOTB on N900, but future H-E-N might actually look at it.

/j

Re: Soldering advice needed for re-attaching N900 USB to mainboard.
 

http://talk.maemo.org/showthread.php...96#post1026196 and prev related posts. Thinking about the same, thought of a battery mod to have the pads on "outer" side so pogo pins can attach thru small holes in back cover, place the protective gear somewhere where battery plastic allows to mill out some volume, and place some mini spring loaded contacts on "bottom side" of battery

/j

Re: Soldering advice needed for re-attaching N900 USB to mainboard.
 

There has also been a power-mat mod done to charge using the under-side pins in a wireless way. Similar approach without the need for physical alignment or external contacts.

Re: Soldering advice needed for re-attaching N900 USB to mainboard.
 

Where can I buy a bottom mount micro usb port. Because on Ebay only top mount I found. From Mouser the shipping is too expensive. The port is £1 and shipping is £30.

Re: Soldering advice needed for re-attaching N900 USB to mainboard.
 

Hi, just look for "nokia usb socket" or "micro usb socket". Those for other models also fit. I can confirm, that this one from ebay: "Buchse NOKIA 6500 8600 6555 8800 7900 Micro USB Connect (300505065513)" for various other phones fits.

Re: Soldering advice needed for re-attaching N900 USB to mainboard.
 

Thanks. After a little more research on eBay I found this. It says for N900 and is cheap.

Re: Soldering advice needed for re-attaching N900 USB to mainboard.
 

Hey! I wonder if you can help me find the right connector, I can't find it anywhere :( I really want to fix my n900

Re: Soldering advice needed for re-attaching N900 USB to mainboard.
 

You can try the link in the above post. I bought a few of those and the seller says that are compatible with N900

Re: Soldering advice needed for re-attaching N900 USB to mainboard.
 

I managed to repair my faulty USB port today. Many thanks to everyone to posted pictures to this thread, it was of immense help.

I apologize for lack of photos; I found myself reaching for my N900 several times to take some shots, then realised it was in bits in front of me :P

My port was still attached, but had dry solder joins on one or more of the 5 pins connecting to the pcb. (this means the solder has snapped and the legs are not bonded to the board, they are just touching it [occasionally, in my case].)

This symptoms of this are:
- Phone charges but only if you turn it upside down
- Phone charges but only if you fiddle with the usb cable till it's "just right"
-Phone charges when you hold the usb connector in the socket (and possibly gently push)

I found it got progressively worse to the point that I would spend 5 minutes every night making small adjustments to the cord and phone until it would start charging.

I pulled the device apart according to Nokia_N900_RX-51_Service_Manual_Service_Level_1_2.pdf (google for it).

I stuck a small piece of paper over the camera lense to prevent dust getting in, and removed the RF shield from the chip immediately next to the usb connector. The little clips on the side just click off with a small flat blade screwdriver. I then got some small side cutters and cut a very small section out of the RF shield rail (what the RF shield clicks down on) to gain access to the back of the USB connector. This should expose the surface mount solder points.

I then wound a pin around the end of my soldering iron, tinned it on and chopped the end off the pin off (it was too fine). From there I managed to heat up each contact till the solder re-flowed (I didnt apply new solder at all). Its very difficult to see exactly what you are doing with bare eyes - you cant tell if the solder has remelted. I experimenting with various lengths of time holding the tip onto the joins. Between each attempt I connected the screen and held a battery on the back of the board, to fire the device up and test for any improvement to the usb connector. I found that the best approach is applying the tip from a 45 degree angle, to clear the RF shield bracket and have a degree of visibility to the pins.

Once I had it reliably charging, I scraped away 1mm of green enamel on either side of the connector where the sides are soldered down, and applied a nice amount of solder to each side to lock it into position forever. Its imporant to not heat the connector up too much else the internal plastic parts will melt, but enough so that the solder "flows" onto the connector and onto he board where the enamel has been scraped off. Also take note of where the board fits into the plastic shell, there is a screw right next to one side of it; too much solder on the board will mean the board wont sit correctly on that mountpoint.

Hope this helps someone.. attached are some shots of my makeshift SMD soldering iron mod.

Re: Soldering advice needed for re-attaching N900 USB to mainboard.
 

Could somebody post again the picture ?
Thank you.