Broken MicroUSB idea: Creating a new connection
 

I've read about somebody wanting to try this, or perhaps achieved it, but can't find where.

http://www.cpkb.org/wiki/Nokia_N900_pinout

and

http://www.cpkb.org/wiki/Micro-USB_pinout

Using these, the back of the pcb of the n900:

http://www.cpkb.org/images/thumb/9/9...900_pinout.jpg

Microusb cable:
http://www.cpkb.org/images/thumb/0/0...b_pinout_2.JPG

* 1 - (black) GND / ground
* 2 -
* 3 - (green) Data +
* 4 - (white) Data -
* 5 - (red) VDC / plus / +5V
* 6 - shield

Using this data:

Is it possible to create a new Microusb connection? Where my microusb connection was, there are no more metal solder points to be able to repair the microusb port.

Unsure 100% of the following:
Line up TX with Data +
Line up RX with Data -
GND with GND

But then where does one obtain the positive voltage (usually 5v). On the cable this is VDC +5v, but the battery positive cannot supply this voltage.VCC according to the link "Common Collector Voltage - main power supply ( usually 5V )". But would this work? the provided link doesnt actually specify where VCC is.

The cable would then be routed to where the microusb was. So I'[d attach a new microusb port, with the cables being soldered from the new microusb port, to the connections above.

edit: I already have a desktop charger. I also use TinySMB to transfer my files to and from pc. The only reason I'd have for doing this is if I want to reflash.

Re: Broken MicroUSB idea: Creating a new connection
 

http://talk.maemo.org/showthread.php?t=54762&page=2
http://talk.maemo.org/showthread.php?t=45385

Nice to have some good tutorials for the USB fix.

Thanks all :)

Re: Broken MicroUSB idea: Creating a new connection
 

yep read those. however if you read my post again, ive mentioned i have no metal tracks on the pcb for the microusb anymore. which means i cannot use that area. hence my idea of making a new connection from the areas ive listed above

Re: Broken MicroUSB idea: Creating a new connection
 

That's an fbus or mbus connection, not USB, by the looks of it. I think your best bet is to solder to the red and black components as indicated in this image http://talk.maemo.org/showpost.php?p...3&postcount=12
If you've torn those off too, it's probably too late.

Re: Broken MicroUSB idea: Creating a new connection
 

could those rx/tx lines be used as TTL serial? that would open a lot of new areas for the N900.

Re: Broken MicroUSB idea: Creating a new connection
 

Can you confirm if you managed to do this? I've recently acquired a second-hand n900 with broken USB port, and was wondering if I could add my own port using the connections identified in the 1st pic.

But the question is, where to get the +5 volt connection from?

Re: Broken MicroUSB idea: Creating a new connection
 

IIRC these are debug/UART/serial ports, not USB ports.
Who knows if they're DC5V. You'll need a USB host controller, and not any random pins like JTAG/GPIO.
Although, if they /were/ GPIO, anyone want to try strapping an Eye-fi card to them?

Re: Broken MicroUSB idea: Creating a new connection
 

Ah, so I'd have to take the connections from where the old USB port has fallen off? Hmmm... shame, as the port appears to have taken some of the board with it - therefore a repair is gonna be very awkward.

Thanks for your answer...

Re: Broken MicroUSB idea: Creating a new connection
 

Actually, you do get access to the USB connector via these pads.
I managed to charge the battery having +5V and GND connected to a 5V power source.


Please be aware that this is highly experimental and you do this all at your own risk!
By messing with your device in this way you'll for sure loose warranty!
Furthermore, you may damage or even destroy your device!


Having said that, lets move on:

In order for the charging to begin +Data and -Data need to be connected (via some resistor ~2.5 Ohm) prior to connecting the power source.
Else simply nothing happens. ;)

Note: I measured whats going on with the default power supply on +Data and -Data and it showed a resistance of 2.5 Ohm.
I used a 2.2 Ohm resistor and also tried to simply shorten +Data and -Data.
In both cases the battery started charging after connecting the power source.

I attached an image of the pins I used.
Edit: I added my stuff in orange color.
GND of course still is the same.

Please note that:
And also have a look at the rest of his post on the second page for much more useful information!

Re: Broken MicroUSB idea: Creating a new connection
 

Hi,
good work, Wonko! :)
Anybody got a working USB data connection over the pads in Wonkos picture? I tried it, but without powering the device over the USB pads, but with battery. The N900 never appeared in /var/log/messages. Could it be possible, that an USB data connection needs also external USB power? Maybe to activate or power up some controlling chip?

Re: Broken MicroUSB idea: Creating a new connection
 

Edit: Sorry, scratch that...
While charging worked with that setup an USB connection with the normal port was not possible anymore. :o

I think I'll revert back to plan b and use a small dip switch until there is a more elaborate solution...

Re: Broken MicroUSB idea: Creating a new connection
 

So it'll charge by shorting data+ and data- with 2.2ohm resistor?
But obvisously a data connection will not be possible then.
So how can we can get a working data connection using those pads then?

Re: Broken MicroUSB idea: Creating a new connection
 

..there is the USB connection!! :)
I can confirm that the two pads marked as Data+ and Data- are working. I just flashed my device using them, 5V+ and GND.
The device was only recognized over USB while also the battery was attached. That's a little bit tricky if you have it open and wires to the pads connected, but it worked! YEAH I got my phone back :)))

Re: Broken MicroUSB idea: Creating a new connection
 

where can i buy an replaement usb port?? mine is broken

Re: Broken MicroUSB idea: Creating a new connection
 

Sweet! Nice to see you got it working. :)
And, yeah, it is a little bit "delicate" to mess with the device in this way. ;)

You only need to short-circuit these when you want to charge your device with a custom charger which only supplies +5V and GND.
If you want to connect your device to a PC via USB or use e.g. the Nokia supplied chargers via USB nothing special needs to be done.


Anyhow.. as you need to solder inside your device you'll for sure loose warranty. And having custom cables around in your device might also be something problematic. E.g. the back-cover may not fit anymore or you may attract attention in e.g. airport security checks (like jd4200 mentioned over there: http://talk.maemo.org/showthread.php?t=72753&page=2 ).
Still, for people like me, who have no experience with SMD soldering, using these pads is a nice alternative to disassembling the device and messing with the very fine connections near the micro USB connector.

Re: Broken MicroUSB idea: Creating a new connection
 

Hello Lazart, can you be more especific about who you manage to flash your N900 using this connections? would be great if you could take some pictures of the cables and the connectors you are using.

Thank you, and congratulation about your reborn N900.

Ed

Re: Broken MicroUSB idea: Creating a new connection
 

Yes - please provide more info about which connections etc you used.

I'm looking to bring my 'spare' n900 back to life :)

Re: Broken MicroUSB idea: Creating a new connection
 

sorry, that it took so long, I wanted to make pictures before I post. Pictures come later, now some info on my hack, because this is a real cool community which helped me a lot:

I soldered 4 wires on the pads (D+, D-, GND and 5V), about 5 till 10 cm long, on the pads of the N900. The device has to be disassembled for that, I couldn't solder on the pads as it was assembled (maybe with a very small oldering iron it could be possible).
I put the wires through the holes by that you could usually access the pads if the device is put together (and we need it to be together.. :))
As mentioned there was no working connection without the battery, so I had to put the battery back in with the wires going by it. That's why you have to use really thin wires.
After putting the device halfway together, at least the battery must have a connection, I connected an USB cable, which I cut on one side, that it has just the plug for the computer and wires on the other side, that where temporarily connected to the wires on my phone. Now my PC recognized a new USB device, rest is flashing, see in the wiki.
Those wires are still on my phone, I'll keep them until I have a USB socket mounted again.
The back cover still fits, a bit harder than usual and I open it regulary if I swap the battery, charged at a wall wart charger.

Mind that 5V and GND or any connectors of the battery should never be shorted!

Re: Broken MicroUSB idea: Creating a new connection
 

some pictures..

1st: closed n900.

2nd: opened with battery, the grey wires are for charge (directly connected to the battery pins (not for USB!!), now obsolete because I have a wall wart charger and 2 batteries.

3rd: battery removed. the wires go to the USB pads.


I know, it looks awful but it works :D

Re: Broken MicroUSB idea: Creating a new connection
 

The D+/- pins are correct but missing any ESD protection, so are not exactly a replacement for the USB receptacle contacts. Refer schematics, V5301 and Z5300 - the D+/- pad shown here are the J5300/1 testpoints. Using these without the ESD protection from those components may cause damage to the chips that interface to the USB.

Same applies for 5V VBUS: correct pad but a lot of missing protective gear:
F5300 2A fuse
N5300 reverse polarity (and OVP?) prot diode
C5300 100nF feed-thru capacitor to filter spikes and RF
C5301 27pF capacitor to further filter RF
L5300 choke to filter ripple and spikes
the pad itself seems isn't shown in schematics

For fixing a broken USB receptacle there are definitely better ways than using those pads.
[EDIT]
Fixate receptacle like this: http://talk.maemo.org/showthread.php...991#post547991 - get the pic.zip form there http://talk.maemo.org/showpost.php?p...7&postcount=27 for details how to deal with contact pads came off, or >>NEVER use epoxy glue!<<

or just the excellent thread >> Fixing USB port, before and after it is to late. (All info in one Thread) (See POST #1) <<
[/EDIT]

ID pin you'll probably not really miss, as it's basically useless for a micro-B-USB-F - it's a OTG thing and N900 can't do OTG. H-E-N doesn't need ID


The D+/- short for fastcharge is specified as a simple short. No need for any resistor.

One last thing: Battery minus is NOT GND! Don't use it like that

HTH, click thanks if it did
jOERG

Re: Broken MicroUSB idea: Creating a new connection
 

This is outstanding work, thanks all! I will reference this on my blog soon.

Re: Broken MicroUSB idea: Creating a new connection
 

Shhhh - don't tell Abill because this is his secret..

Re: Broken MicroUSB idea: Creating a new connection
 

Very disappointed and do not know what to do ... unfortunately I am one of the users of the N900 to it broke the USB, I take it to nokia service from 10 days ago and today received a message saying that it had to offer the phone.

To my surprise I had given a Nokia E7, that no longer makes Nokia N900, supposedly now this is the flagship of Nokia (for price if it is). But as we all know, this phone is a little **** compared to the possibilities of our N900 and other brands.

Do not know if I can claim to Nokia on this central event, but I am very saddened by the loss of this great N900.

Maybe try to sell cheap and buy me Galaxy S2 | | HTC Sensation with vodafone ..

I'm screwed.

Re: Broken MicroUSB idea: Creating a new connection
 

what is cheap, im on the lookout for one more, and what country do you live in (keyboard layout)

Re: Broken MicroUSB idea: Creating a new connection
 

OK I have recently joined the broken USB club ( :( ) . I understand your point about the circuit protection, however I would like you to answer these 2 questions for me.

1. If I developed a circuit board which had the protection your talking about to use these easily accessible points as my new USB connection. Can you detail the entire circuit from the USB cable back to the test points.

2. If there are "easier ways to fix those pads" please detail how you would do it for someone who may not have access to the proper tools, or the small circuit expertise to attempt such a fix.


I have an option of sending away to a U.S. repair company however if it will just break again over time is this a "better solution"?

Please don't take this post as confrontational it really is not meant to sound that way. I just really want a long term solution for my N900. I have been very carefully with my n900 for the last year and a half, I would charge it almost 2x a day. Now I have an external battery charger and a spare battery. However I still haven't figured out a way to easily transfer files to and from my device, Synchronize my contacts, and messages, or flash my device.

I am hopefull I can find, or make a long term solution!

Re: Broken MicroUSB idea: Creating a new connection
 

Could this internal USB-Port be used for an internal USB-Harddisk?
(Superflat with a special battery cover)

Or for an internal SD-Reader (as Swap)?

Re: Broken MicroUSB idea: Creating a new connection
 

Technically yes, but you need to use H-E-N first to activate SD-Card reader and then enable swap.
This will seriously drain you battery, but should work.

Re: Broken MicroUSB idea: Creating a new connection
 

1. I'm new to the forums here, so I hope im not giving you any misinformation (xD). Attached is the section from the N900 schematics related to the VBUS.

Re: Broken MicroUSB idea: Creating a new connection
 

Guarranty is for 2-years, no? If you had the patience, may be now you can get a N9/N950 (who knows) :D

Re: Broken MicroUSB idea: Creating a new connection
 

Sorry to dampen your mod but for the above reasons it is just not a good option and wow a hell of a lot of work to this when all you need to do is open it up and repair the usb port properly, this takes away the risks of this mod and the wires hanging out everywhere.

Lets face it once you even touch a Nokia device with a soldering iron the warranty is gone anyhow so better to open up and do the job properly !.

PS and if i am not wrong this mod will bypass the charging circuit and not a wise move at all.

Re: Broken MicroUSB idea: Creating a new connection
 

it doesn't bypass the charging circuit, but all the protection components in charging path, incl the 2A fuse that could stop your device from catching fire

/j

Re: Broken MicroUSB idea: Creating a new connection
 

The protection is to isolate $random_cable introduced mess from N900, as

there's little use in doing sth like

Also without proper tools and experience/expertise you'll fail on that approach as much or even worse as/than you'll fail on the suggested proper fix of USB receptacle, as shown in the thread linked to in a former post of this thread



For a general note and advice regarding these testpoints: they are fine for using a properly designed service jig mount or sort of cradle to contact them. They are also ok for an emergency recovery setup, given you make sure there are no wrong signals, static charge, wrong voltages and/or polarities and so on. Most important: Alsways make sure to first connect the GND of your auxiliary contraption and the N900 GND, to avoid static discharge smoking up N900's chips


/j

Re: Broken MicroUSB idea: Creating a new connection
 

It may be useful at this point to "reboot" this thread by consolidating the best practices, pictures, diagrams and advice into a single post, based on the back-and-forth here. Anyone willing?

Re: Broken MicroUSB idea: Creating a new connection
 

The most important ting here is ESD protection, i blew the fuse in mine, but this was due to experimenting late at night and then reversing polarity of the homemade USB charging system........

So i would say put an ESD protection on the data lines and that should be enough.

NOTE: I fixed my USB with removing the fuse and soldering a thin wire in there in stead, and yes this is not the best solution at all, but it has worked for some months now, of course i only use the USB connection once a week on average due to my charging system.

I bet i will have the N900 that lasts the longest in the USB area :D

Re: Broken MicroUSB idea: Creating a new connection
 

How about building a flashing/usb connection rig? I've been thinking about this idea for a while. The schematics show a FS-94 flashing rig, but there seems to be very little on the internet about them.

They can definitely be used for the purpose of flashing though, as this blog shows.

I bought one of these of ebay. The box is plastic and the pins are springed so that when you plug in the box the contact is firm but in the wrong place for our purposes. But it does provide the dimensions of a would be flash box made out of metal, or perhaps it could be lined in foil and grounded? The protection circuit could then be inside the flash box, and a battery would be fixed beneath the box.

So from bottom up, you would have battery>>flash box>>n900.
You would then have a microusb connector mounted on the box.

This approach would have the benefits of allowing phones with pcbs too far damaged for repair to be repaired, it would also save you from having to open your phone, and stop it from looking like a bomb when going through customs!

Obviously this couldn't be carried around in your pocket, but for flashing/usb transfers purposes it would do great.

If someone could make a properly fabricated pcb that was 5-10mm thick then maybe a thin box could be made that would sit between a battery and the phone and could sit inside a mugen battery cover modded with a microusb port. This could be the complete solution.

Re: Broken MicroUSB idea: Creating a new connection
 

so if i understand this correctly...the safest way to provide the +5V is from the original usb pad since it routes it through the circuit protection..BUT we can also rebuild the circuit protection but then we deal with the issue of the connection from the circuit protection to pad..or we can just connect directly to the pad and suffer massive consequences if something goes wrong

bottom line: the only viable way to provide power is through the original route?

Re: Broken MicroUSB idea: Creating a new connection
 

Exactly. And same applies for D+/- to a slightly reduced degree
Though, as mentioned, a properly designed connector jig similar to the one 2 posts above with a few improvements, that also cares about ESD and protection at large, will work as that's what the pads are made for. Soldering some wires there and routing them to a USB receptacle won't pan out in the long term.


[edit] Thanks to suggestion 2 posts above, and of course thanks to those nice fellows donating to h-e-n, I ordered some of those connectors, let's see what we can do with some modding. Just in case you feel like donating as well, here's some Donate button

/j

Re: Broken MicroUSB idea: Creating a new connection
 

Keep us informed about this please ;)

I will donate when i receive ;)

Re: Broken MicroUSB idea: Creating a new connection
 

Hello. I tried to solder the usb port how the other tutorial described but the data pins chip's 2 connectors broke as well. Can I use the two mentioned pads for data lines and still use the old +5v and GND. If I understood well I will be keeping the protection for the 5v but loosing only the esd protection.

Re: Broken MicroUSB idea: Creating a new connection
 

Basically yes, though I'm rather sure your soldering and wiring skills won't result in a proper USB2.0 compatible signal path either. Anyway you're probably relatively safe, as each USB connector, on mating, has a make-GND-first property, so unless you plug in open-ended USB cables (I.E. cable not connected at other end when plugging it to N900) you probably can't create a critical ESD event on datalines by using the D+/- testpads for alternative connection of a mounted USB receptacle - only if you properly route the wires from receptacle to testpads away from case and flat on PCB surface all the time.

I'd rather suggest you send photos, I give advice for a better way to connect D+/-, and you find somebody skilled enough to do the soldering without breaking components again.

cheers
jOERG