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Originally Posted by abill_uk View Post
For this thread to explain everything properly there has to be a picture step by step from taking the N900 apart to the actual job of soldering down the jacket to the earthplain.

I have now got a device with a broken lcd and i will use this to provide pics step by step but please allow me a few days for this and i will talk to dr_frost_dk about putting the pics in the relevent place on this thread, work this as a team effort so to speak.

Please understand that to do the PREVENTATIVE repair your not dealing with any small components as the jacket of the usb port is actually big enough to see and work on with normal soldering iron so please realise this as it is a very simple mod to do, the hardest part is actually taking apart and putting back together the N900.
Or just link to the first post of this thread how to open N900.

Like this:
or this:
(These videos shows how to open N900 more than it is needed for this USB-port fix hack.)

Last edited by zimon; 2011-09-13 at 22:12.

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Has come to my attention that 'blue_led' also did the soldering down some time ago.
added link in post #1

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Your post should be in the first place in the n900 section.

Don't know why people are so lazy to wait for a broken usb and then search for a howto repair it.

Fix it today.


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Where is the pic of the components the pads link back too? it needs to be on this thread so people know where to link wire to what component.
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Found it on your first post but is not here already to view, only as a link.
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Originally Posted by dr_frost_dk View Post
No it won't, why, well you will apply glue from the USB to the circuit board, now you are just gluing the metal down to paint that doesn't stick to well (easy to scrape of to prepared for soldering) and if you glue it then the day will come that you find a USB that is broken off with a base of green paint hanging on to it.

Why don't you out there listen to people that actually KNOW how stuff works, i to thought about gluing mine, until i opened it up an looked at it, then i concluded that it would be a waste of time when considering that the glue will just rip the paint up with it or the worse possibility that the glue gets inside and you can't use the USB at all.

REMEMBER i have already done the soldering to 3x N900 without any problems at all.
dr_frost_dk, I do appreciate your work, but please actually read the post before you flame. I'm not sure by any means that epoxy putty is "better" or "worse" than soldering, but, the decision to go down that route is informed by every thread on this forum, including yours, and I post here because I'd be interested in constructive discussion about it. Your considered opinion would be very welcome indeed.

First, we're not talking about a "glue" so much as a "filler"; this is key to the mechanical strength of the fix. By physically filling up the space around the sides of the USB port, we're not gluing it down to paint, we're building a foundation that should stop it flexing even the slightest bit relative to the board; "adhesion" is less of a concern to me than sheer "mechanical reinforcement". If the port cannot move at all, the adherence per se will never be tested. I actually ended up going over the top and back of the port as well, with the port itself protected by having a cable inserted.

Second, epoxy putty is more solid during application than either glue or molten solder, meaning less chance of getting it in the USB port - but it remains workable for a couple of minutes, so there's time to shape it, move it or remove it once it's in place.

Third, your "without any problems at all" is subjective. You had to file away part of the case to fit the board back in after soldering, which may not be a problem to you, but does mean that more tools and equipment are needed, and makes the process more complex. In the photo below, to the top right hand side of the port you'll see the indentation in the putty from refitting it into the case while still soft.

This means I don't have to mess about modding the case in any way, and also has the advantage that the lump of epoxy fits up hard against the case. There's far more putty under the sides and the back of the port than is obvious from this photo; I did the sides and back of the port first with the microSD board lifted off, trimmed it back level with the board and then put a lump over the top (with a cable in) before final shaping.

The end result
  • uses a semi-solid material which stays where you put it
  • uses a non-conductive material that can be applied liberally
  • surrounds the port completely, even filling the holes in the jacket, without rendering it inoperable
  • gives plenty of surface area in contact with the main board (contact with the microSD board is incidental)
  • avoids fouling the case, requires no case mods, and actually reinforces the repair against the case as well as the board
  • requires no soldering iron or Dremel-type tools for case modding and is cheaper to implement on a small scale

Obviously, this hasn't held up for a year yet, so I can't say it's better or worse than soldering the port down, but it is cheaper, more accessible, a less complex procedure (no case mod) and more comprehensive in reinforcing the port from all angles and in all directions. You can see the epoxy filling up the back of the port in this second photo - and the port works just fine for both charging and data after being completely encapsulated in epoxy. In order for that to pull out, it's going to have to break the case too.

My hope in documenting this is that for me at least, it addresses most of the concerns that I had after reading the many posts linked to from this thread about soldering or liquid glues, and it's a fix that's available to Joe Average in his bedroom without a workshop. Comments invited.

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Well depending on how you solder down the USB port case modding is not needed per say, and also i only used a small cutter for the case, didn't need to get the proxxon out or anything.

Again case modding is only needed if the USB won't sit flush when putting the N900 back together.

And in light of only using soldering iron and small cutters then you cant really argue on price, the 2-component (which can be very fluent or hard depending on type) can be pretty expensive i might add, i use it alot for various purposes and i have countless of 2-component glue laying around.

Last but not least, lets say something goes wrong anyway with either mod, whats easiest to correct?
- unsolder the port and fixing it
- trying to get glue off that was designed not to come off? (this is not hot-glue we are talking about)

Last edited by dr_frost_dk; 2011-09-17 at 02:08.

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on the subject on making a new connection i found this ESD filter that could be used.

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My take on epoxy: besides all will-it-stick-to-the-board? concerns and possible trouble on re-repair, epoxy always will be way more elastic than the rigid solder, so when force applied to the receptacle I guess the solder joints will break no matter how much elastic plastic material (aka epoxy) sits around it and tries to reinforce it. (think about it like "how much scotch tape to wrap around a glass tube to prevent it from breaking when you bend it")
So thumbs up for the soldering method, frowning on the epoxy method (which up to now hasn't proven it's effectiveness, unlike soldering which is pretty obvious to improve things)

PS: Note please that in the picture 3 up the short connection next to "GND" from rightmost to 2nd f. r. pin is incorrect. See - pin #4 is ID pin and you best leave it alone if you can't manage to resolder it.

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Last edited by joerg_rw; 2011-09-17 at 13:56.

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Although I totally give thumbs up for soldering method for obvious reasons, I would not depreciate epoxy thing. There are many epoxy types around, some of them producing heavy, metallic/rockish thing, that even produce semi-metallic sound, when hit I would say that those types are less elastic that solder, really! I think it's going to break like stone, instead of changing shape, even for a while.

Still, IMO soldering is much better - because soldering characteristic, including shallow diffusion - and I'm going to do it. Probably, after good soldering, I'll also "encapsulate" it (in sane manner, of course) in good'old'epoxy. Which I think of as gaining best from both methods, unless someone prove that I'm wrong.


BTW, I totally agree that "modding" cover to fit soldered port is eas and doesn't involve any complicated tools. Can be done with sandpaper, if with nothing else.
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