Re: N900 partial disassembly and USB fix
 

thanks for the post and a quick one - the bezel aeound the keyboard in my n900 is kinda loose e.g it moves so is it the case of that teeth not fitted in its place?? thanks

Re: N900 partial disassembly and USB fix
 

an idea: do you have a noncritical micro usb plug that you can stand to potentially lose or replace? the only thing that will really fill the whole socket cleanly and be super easy to remove is the microusb plug itself. ideally you should be able to do this epoxy job without getting a drop inside the socket, but its there just in case. Even if you were to get some inside the jack you would be able to easily remove it somewhere between epoxy set and epoxy cure and see evidence of epoxy on your plug, while you could still remediate if necessary. Easily worth potentially sacrificing a $3 generic microusb to USB-A cable rather than permanently buggering your jack

Re: N900 partial disassembly and USB fix
 

First of all, as I said in my original write-up, I am not just gluing the USB port to the lower PCB alone. That would not be strong enough. I am encapsulating the USB port in epoxy, and using the heatsink behind it, its own solder points, the upper PCB, the upper PCB plastic support, etc to strengthen its adhesion.

And I actually did the test you suggested. I took an old SODIMM stick that visually has a PCB almost identical to the N900 (the green mask is identical, same types of components spread around, etc). I applied blobs of epoxy at random over its entire surface.

Some epoxy blobs covered memory chips, others touched the solder mask and metallic connectors, yet others just sat on top of the solder mask with no contact to anything else.

After letting the epoxy cure for less than 1h, I tried removing one blob that was covering just the solder mask. It was purely sitting there, not touching any components, memory chips, traces or metallic components. I had to pry it off with a screw driver, applying so much force that I would have ripped off your solder job and the USB port with it.

Yes, I know epoxy is not ideal under these circumstances. But I'm willing to bet money that properly epoxying the USB port will be just as strong if not stronger than resoldering two contacts. And I did not point this out before, but you only really strengthened one side, the other is just as weak as before. To get to the other side, you would have to take the upper PCB off, which I think is impossible without ruining the sticky foam and who knows what else.

Lastly, this is the epoxy I used: PermaPoxy General Purpose Epoxy Feel free to test it yourselves before disassembling your N900s. Just make sure you follow the instructions on the back of the packaging regarding mixing, etc.

Update: It is now about 12h of curing, and the epoxy strength is identical to that after 1h of curing. But draw your own conclusions guys...

Re: N900 partial disassembly and USB fix
 

I don't argue with epoxy it's your business how deal with.
at beginning epoxy is sticky but in a few weeks epoxy become more rigid and prone to detachment.
for both solutions, even epoxy have infinite strength, final strength uf usb port is provided by adherence of copper layer to epoxyed fiberglass substrate

for those who want use epoxy : try to get stretch foil . thickness is only 23 microns
http://www.dapas-konice.cz/images/stretch.gif
put it over plug and insert into usb socket. doing like that you protect contacts and put a polypropylene layer between epoxy and plug. epoxy don't adhere to polypropylene

Re: N900 partial disassembly and USB fix
 

Allright guys, this will be my last update to this thread. The how-to will stay up indefinitely (until Google decides I've taken too much bandwidth). I did my absolute best to come up with a method that will improve the USB port strength without endangering the N900 internals.

I even verified that the Epoxy I used is safe for electronics, that it doesn't shrink (I even called Permatex and they confirmed it) and that, while far from perfect, it does stick to PCBs. Now only time will tell. But I will say that I've used Epoxy in a variety of circumstances, and it held up far, far better than any other adhesive I've ever used.

Good luck with any of the fixes you chose to implement.

Re: N900 partial disassembly and USB fix
 

not my experience - I've got some heavy use items (metal to plastic) with epoxy fixes applied that hold up well > 3 years.

I did follow your advice to scrape the green off of the main board

I cleaned the port and board with acetone before applying the epoxy

I'm confident in the fix - thanks for the pics & writeup cr0c0

Re: N900 partial disassembly and USB fix
 

Ok after saying it was going to do this over a month ago I finally got around to it.

From my side I scraped the solder mask on the right side of the usb port away so that I could run a bead of solder along the side of the usb port. Secret here is to use a blade on the soldermask and very gently scrape away - rather use 100 light scrapes and slowly remove the mask then doing it on one or two scrapes and risk removing the coper layer. The left side of the usb port was too inaccessable to try get a soldering tip in without risking melting the ribon cable going up to the board above the usb port.

I then decided to add epoxy too - on the left of the usb port and aboveit. I used JB Quick since it sets nice and fast. To prevent any epoxy from going into the usb port I get a existing usb cable and sprayed some WD40 onto it and put this into the socket. The idea here is that if any epoxy does get through the gaps in the usb port, the epoxy will not stick to the plug because of the wd40. I left the plug in for about 4 minutes (jb weld was nearly set by then).

Phone is reassembled and working 100% - hopefully this will give me piece of mind when plugging it into the charger. As someone who bought my phone from an importer in Australia I doubt I have a warranty anyway.

Re: N900 partial disassembly and USB fix
 

I can see that both the points are soldered, is there no short circuit??

Thank you..

Re: N900 partial disassembly and USB fix
 

no . both points are part of the receptacle metal body soldered to ground.

Re: N900 partial disassembly and USB fix
 

hi
i have one question :/
if mi usb port has fall off, can i fix it ?
:S

Re: N900 partial disassembly and USB fix
 

It's not too hard to open both metal cages next to the USB port carefully with a needle or very thin screwdriver. Then, the upper board with the lids of the cages glued on will swing away, giving more room for soldering.

I had to open that cage recently, because I needed to rework the eMMC for bad data connection after the phone had dropped.

Re: N900 partial disassembly and USB fix
 

Looks like there might be enough space to replace with a full size usb port... now there would be a cool mod.

Re: N900 partial disassembly and USB fix
 

My usb port gone out and i am trying to solder the connections manually to the PCB. i have done all except the pin4.
Is the pin4(ID) of the USB is necessary for flashing the mobile.
Whats the use of it when the mobile is connected to the PC.

Re: N900 partial disassembly and USB fix
 

Hi,

I just bought a second hand N900, the USB port is still in good condition but I am thinking about doing the epoxy method to prevent any damage (I have already filed the tabs on the USB cable)

Is there any feedback from someone who did this a year ago about the long term results of this procedure?

Thanks!

Re: N900 partial disassembly and USB fix
 

reinforced with epoxy jan 2010 & still working great.

Re: N900 partial disassembly and USB fix
 

I've done it a year ago too (and have the pictures to prove it :P ) and it's still holding perfectly. I also filed down the hooks on all my micro USB cables, which undoubtedly helps a lot as well. Mind you, my N900 has been charged or connected to the PC at least once a day, sometimes more.

Re: N900 partial disassembly and USB fix
 

I recently lost a N900 due to the usb port falling off, I'm going to try this as soon as my new one arrives, because other than the usb port i never had any issues... (and that n900 was going on 1 year+ of heavy use)

Are the tabs on the usb cables the 2 tiny clip things on the underside?

Re: N900 partial disassembly and USB fix
 

Yeah same questions, are those 2 tiny long clips the tabs u are referring to??

Re: N900 partial disassembly and USB fix
 

Yes they are the two small "hooks" that are clearly visible in this picture:
http://upload.wikimedia.org/wikipedi...B_USB_Plug.jpg

I suppose you could also remove them with small pliers, but filing them is probably cleaner.

Re: N900 partial disassembly and USB fix
 

how to make slider smooth again. my slider is very tight now.
It has made scratches on my keyboard both sides

Re: N900 partial disassembly and USB fix
 

hi all,
so many people fixing their N900 USB :) I tried that, too. Some pads where gone but those 2 for USB power have been there. Unfortunately the USB-Socket filled up with some solder, and as I tried to plug in the cable, the whole thing jumped of again - and now there aren't any more pads left!

Does anyone know where exactly the conducting paths of the USB port go? (They aren't vissible, must be a layer in betwee) That's the only chance for getting USB back.

I got the service manual with the schematics but there's no layout.


greets,
Simon

Re: N900 partial disassembly and USB fix
 

http://icroon.eu/pic1.jpg from original post http://talk.maemo.org/showpost.php?p...3&postcount=12

Re: N900 partial disassembly and USB fix
 

I think most of the people get their sliders scratched a bit. If you feel the slide is too tight, unscrew a bit the 4 screws that hold the upper side (with a PH0 screwdriver) until you feel the slide is how you want it.

Re: N900 partial disassembly and USB fix
 

Big thanks for this pic, My N900 fell and snapped out the USB port and this was the image I needed to get everything soldered back down. Talk about sweating out some micro repairs, I had a LED flashlight, solder, soldering iron, and an eye loupe all a few mm from the board. I used the idea up the thread to scrape the green covering from the ground plane of the PCB making a larger area holding down the USB port. I ended up having to lift off the RF sheilding and even snipped away the wall that was preventing me from getting a good angle at the tiny port leads. Then I used alcohol and a swab to clean up the flux mess when I re-tinned the contacts, I suspect Nokia uses 0% lead solder for enviro reasons but I used 40/60 solder which I think is a bit stronger and flows better.
I still worry as I use a dynamo charger and rigid mini-microUSB dumb to smart charge tip on my bicycle to charge the N900 as I commute, I might get a USB cable and try to carve it down to nothing attach a four lead ribbon cable or the existing wires and let all the stress and damage hit the sacrificial bit of cable, if this remounted USB port ever goes again it will be catastrophic.

Re: N900 partial disassembly and USB fix
 

Ha ive not been around for a while but still have my N900 all tricked out and working fine unit a week last friday I was at the office and my N900 was playing just fine via the FM transmitter to the workshops Radio system, nice!!! and on charge via the workshop pc, nicer!!! when from the corner of my eye I saw something, looked to the left to see my N900 smoking "AARRRRRAAAAHHHH" WTF!!! I grabbed the thing in a fit of rage and tried to pull the micro usb connections apart, but they wouldnt free them selves...S*** !!! I shoutted as I paniced and looked at the other end of the usb still attached with a snug fit to the workshop PC...supplying my n900 with 5+ volts of welding connection power.. I yank at the wire a surprised look on my face as the connector came away from its home and the N900 was pulled out of range of the workshop radio... a loud hiss desended upon the workshop and everyone not noticing the comotion earlier turn and looked toward the speakers behind me... I said dammmmnn thing my nokia was smoking from the usb... One of my collugues shouted coming though...as he made his way toward me HTC in hand... pluged in to the workshop pc and accessed his memory card...and good tunes flowed between his darn HTC and the workshop pc. I looked at the lymp N900 in my right hand and looked to the sealing and shouted NNNNNOOOOOOOOoooooooooooooo!. but it was to late the damage was done.

So Ive ordered 3 micros from the bay!! and Im going to do the wiring myself. I will post my results... although in the mean time Im using a battery charger and spare battery to keep me going.. not a bad Idea. and if I need anything from the phone I bluetooth it... so not too bad just madness at the mo.

Loz.

Re: N900 partial disassembly and USB fix
 

if you had soldered it down you would not have ripped it out, cant say anything about the smoke thou...

Re: N900 partial disassembly and USB fix
 

Tried Micro surgury... couldnt do it.. no freekin chance. Its gonna have to go away... but what of my pics!!!! I have some very naughty pics hidden in a (.media) folder cant see them whenbrowsing my photos.. can only when you usb it and add as mass storage...Dammmm it!! So how do I get them off without flashing the thing which I dont want to do anyway?????

HEEEEEEEEELLLLLLLLP!!!!

Loz...

Re: N900 partial disassembly and USB fix
 

You miss read my mail... I didnt trip or anything on the cable.. its ware and tare thats caused the micro usb to short out and then weld the male side into the female..so of cause the micro usb is totalled.
But never mind this now I need help with the post above!!
Loz.

Re: N900 partial disassembly and USB fix
 

use xterm
cd /
find -name *.jpg | more
rm filenameToRemove

Re: N900 partial disassembly and USB fix
 

I could not parse this whole "!!111!!" and "?///?" message, so I also don't have a clue about smoke, but You're not right in USB port topic. *If* You had soldered it out *before* problem appeared, You would not have it ripped down, no matter of situation.

/Estel

Re: N900 partial disassembly and USB fix
 

Do me a favor and explain this in more depth as even though I own a N900 im stil a novis at the xterm commands and what they do. Thanks

Loz.

Re: N900 partial disassembly and USB fix
 

I am going to buy a NEW N900 from a honk kong based seller . after buying the phone how can i check if its a faulty set or not ?

Re: N900 partial disassembly and USB fix
 

you don't have to, this problem has not been fixed, every n900 are faulty.

Re: N900 partial disassembly and USB fix
 

Is appling a adhesive around the soldered microusb port enough?

Re: N900 partial disassembly and USB fix
 

definitely not, think about the force applied to it when you put the cable in or out, the idea is to prevent the microusb port to move, because it may break the solders. In another topic, people said that even epoxy is too much elastic, compared to soldering...