USB thinks it connects but it doesn't.
 

Hi!

I have this strange USB problem with my N900. I consulted my N900-owning friends but none of them had the same, and searching the forum didn't help either, so I opened a new thread. Just point me to the old one if this has been discussed before.

My problem is, whenever I plug my phone to PC with the USB cord, it thinks it connects, but the PC disagrees. The phone detects the cable and I can select mass storage or PC Suite, and it says it connects OK, but I get no mass storage icons or PC Suite connectivity on any computer. Device manager says unknown USB device, and some versions of Windows say the device is in faulty mode or whatever ("vikatilassa" in Finnish). I can't usb-to-usb charge the phone battery either, it says it doesn't get enough power (but normal wall socket to usb charger works np).

Sending files over wifi is a pain in the *** and I'd really like to get the mass storage mode working. Any ideas what might be wrong? I have no idea where to even begin to solve this. I generally don't tinker with the phone much. I've installed a few apps but none of them relate to the usb port in any way.

Re: USB thinks it connects but it doesn't.
 

I hope you don't mind me bumping this just once. I really have no other place to ask. (Nokia customer support? Pfft.)

Re: USB thinks it connects but it doesn't.
 

Sounds like you're not getting data across on the send pin from the N900 to the PC. It could be a dirty contact, or the dreaded USB disconnect problem starting. How old is your phone?

One thing to try would be to check the cable you use and make sure it's clean on all it's contacts. You may also want to VERY GENTLY examine your phone's USB port and see if all of it's pins are clean. (You'll want to focus on the middle 2 pins (middle 3 on the micro). If it's even slightly wiggly, and you're still in warranty, take it to a repair center to get it fixed.

Re: USB thinks it connects but it doesn't.
 

I bought the phone when it came out, December 2009 I think.

Thanks for the reply! I'll look into the usb port. I was aware of the USB port issue, but I didn't know individual pins can be faulty. I thought it just either works or doesn't.

Re: USB thinks it connects but it doesn't.
 

The problem is the port becomes loose and starts to disconnect from the board. That can happen multiple ways, depending on how the port is strained by it's use and where the "faulty" solder was used. It could in fact affect the middle pins first, which would cause the results you're seeing. Or, you could have a bit of dirt or oxidization on one of the pins in any of the connections (PC, N900, or either end of the cable).

Checking the cable for dirt (or using another cable) would be the first thing I try. If not, checking the ports on the PC and/or N900 would be second. Just be careful when poking the N900 port. Being able to use it to charge is great if it's starting to flake. Good luck!

Re: USB thinks it connects but it doesn't.
 

You're lucky to get help from Woody14619, someone who knows what he is about.

I hope the problem is the cable or the specific port on the PC -- they don't always work well. You could try a different PC.

I would get a desktop charger and an extra battery or two. Only use the usb when you need it.

Getting files via wifi shouldn't be all that bad. You might see if you can find a way of doing that which works better for you.

Re: USB thinks it connects but it doesn't.
 

The fact that the normal wall charger works is proof that you don't have the usb disconnect problem, good news. The fact that "dumb" usb chargers don't work with the n900 is a known issue. I think I saw a workaround somewhere but I can't remember where...

Re: USB thinks it connects but it doesn't.
 

I agree completely. Such a nice community here. :)

That's not the problem, I've tried several computers. And just now I got a spare data cable but it made no difference. So unfortunately it's not the cable or the computer, it's the phone.


So the next step is to try to clean the usb port. I poked around with a paperclip and removed some dirt, but that didn't help. What would be a good way to clean the pins properly? I'd prefer not to crack the phone case open if I get a choice.

And I guess there's no chance that this could be some software issue? Any way to diagnose that?


Any recommendations?

My best guess is to find a proper FTP program, upload the files to my net folder and then download them to whatever computer I use. But this is much more inconvenient than just simply plugging the phone in a computer as mass storage, especially because I'm transferring large amounts of large files, the FTP programs I've tried are clumsy (there is hope of finding a good one though), and I have to use the phone's 3G or random WLANs. And bluetooth is hopelessly slow for this purpose.

I suppose I could somehow set up file transfer between a (Windows) PC and the phone over WLAN?

Re: USB thinks it connects but it doesn't.
 

I would advise anyone with a phone to have that. Makes life easier, and they're rather cheep. I picked up a 5800 battery charger for $3, and a spare battery for under $10. Worth the investment IMHO. If nothing else it gives you a way to power the phone to get data off it before sending it off to be repaired if the port does go completely.

That's not entirely true. As I noted above, the disconnect can manifest in many ways. Usually the symptom is noted first in charging, but then most people don't use data constantly where everyone has to charge. It could very well be an initial sign that the port is coming loose. It could be that leverage issues have caused his data pins to disconnect first (they are smaller pads).

The "fix" for dumb cables, btw, is to short the middle two data pins. That usually means taking the changer apart, or splicing it's cable. Doing that tells the controller it's a "dumb" charger and it should just pull whatever load it can from it. Be careful with that though, as it will try to pull up to 500ma from it. If the supply can't sustain it, you could burn out the supply eventually.

I would suggest a pin and a very thin piece of non-dust cloth, maybe dipped in some mild non-oxidizing cleaning fluid. Opening the phone won't help much to be honest, since the port is VERY deep in the device. To get to it you need to basically disassemble the whole thing, and it will still have it's port cover even if you do take it apart.

Unless you're a pro at working with small devices, I would not advise it.

It could be... A "simple" way to diagnose it would be to setup an alternate boot OS (like Android) to boot off of a uSD card. Then you can boot into that and see if it has the same issue. If it doesn't then it's an OS issue (at which point, a backup/re-flash may be called for). It's not likely, but it is possible...

One thing you may consider is TinySMB in the extras repository. It sets up an SMB share on your phone that you can access as a shared folder. Handy for PC transfers over LAN. Your speed limit is more likely going to be how fast your flash memory is, not the connection. If you have a class 8 or better, wifi may slow it down, but if you're using the in-phone memory, or under class 8, you shouldn't see speed issues because of wifi.

Also: If you haven't already, I advise you to use a dremel or a file to file down the teeth on the charger and your data cable on the uUSB side. I did that early on because they tended to get stuck, and am happy I did so. I have a Sept/Nov batch phone, and no port issues yet... :)