Thread: Broken MicroUSB idea: Creating a new connection
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joerg_rw is offline joerg_rw
2011-05-26 , 23:14
Posts: 2,222 | Thanked: 12,651 times | Joined on Mar 2010 @ SOL 3
#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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