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#11
Edit: Sorry, scratch that...
While charging worked with that setup an USB connection with the normal port was not possible anymore.

I think I'll revert back to plan b and use a small dip switch until there is a more elaborate solution...
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Last edited by Wonko; 2011-05-01 at 16:20.
 

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#12
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?
 
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#13
..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 ))
 

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#14
where can i buy an replaement usb port?? mine is broken
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#15
Originally Posted by lazart View Post
..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 ))
Sweet! Nice to see you got it working.
And, yeah, it is a little bit "delicate" to mess with the device in this way.

Originally Posted by MastaG
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?
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.
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Last edited by Wonko; 2011-05-07 at 08:33. Reason: typo
 

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#16
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
 
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#17
Originally Posted by lazart View Post
..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 ))
Yes - please provide more info about which connections etc you used.

I'm looking to bring my 'spare' n900 back to life
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#18
Originally Posted by jedi View Post
Yes - please provide more info about which connections etc you used.

I'm looking to bring my 'spare' n900 back to life
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!

Last edited by lazart; 2011-05-10 at 21:42.
 

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#19
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
Attached Images
   

Last edited by lazart; 2011-05-23 at 19:47.
 

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#20
Originally Posted by Wonko View Post
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.

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
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Last edited by joerg_rw; 2011-09-17 at 01:37.
 

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