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Posts: 272 | Thanked: 108 times | Joined on Jan 2010 @ SD, CA
#1
hi all,
i bought an iphone usb charger and i removed resistors off the data pins and shorted them together. in the past this seems to work with the n97 on a different charger to make it look like a dedicated charger (i will try the old charger with the n9 and post) so this nice new griffin usb cigarrette adapter made forthe iphone is modded as above but the N9 wont recognize it as a regular charger, it says usb cable connected and lists the usb modes, do i need a 200 ohm resistor instead of a short, is it that smart? anyone done this?
 
Posts: 185 | Thanked: 102 times | Joined on Aug 2008
#2
I've tried this on 2 chargers, each time it didn't work and my N9 thought it was plugged into a computer and refused to charge.
 
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Posts: 560 | Thanked: 415 times | Joined on May 2010 @ Switzerland
#3
You need a short between the 2 data pins of max. 200 Ohms. This is the official USB charging standard followed by all mobile phone manufacturer who agreed to use the micro USB port for charging.
Apple uses an own proprietary standard which is not detected by any other phone.

If it still is not workinhg, then check if you really shorted the right pins (the 2 middle pins). I made myself an USB extension cord with shorted data wires and now all charges I have work fine.
Another reason might be that the voltage of the charger is too low. It should be 5V, but at least 4.7V, else the current will be very low.
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Posts: 272 | Thanked: 108 times | Joined on Jan 2010 @ SD, CA
#4
i am definite that the two data pins are shorted. now you said max 200 ohm, maybe the cable i am using has a thin wires. i ll check it out.
apple grounds the data pins through 15k resistors. i removed these. a55wipes.
the third thing left to do is to check the behavior of the n9 home charger.
oh 4th to check output voltage.
 

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Posts: 272 | Thanked: 108 times | Joined on Jan 2010 @ SD, CA
#5
so, the problem was that apple charger isnt just grounded its a voltage divider on each data pin. so you have to remove 4 resistors from two data pins and short the data connections together. it work successfully now, at full power.
 

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Posts: 560 | Thanked: 415 times | Joined on May 2010 @ Switzerland
#6
Originally Posted by balisingh View Post
so, the problem was that apple charger isnt just grounded its a voltage divider on each data pin. so you have to remove 4 resistors from two data pins and short the data connections together. it work successfully now, at full power.
I'm sorry, I could have told you that.

Great if it works now
__________________
On N9 check out this:
CacheMe 4 the N9, a geocaching client / MiniBible, a bible viewer / TheWord brings daily bible verses onto your phone / BatteryGraph to monitor the battery drainage / doublepress2unlock to unlock your phone with a double press onto the power button / GPRS Data Usage to monitor your GPRS data usage /
and more...

On N900 check out this: SleepAnalyser to analyse your sleep movements / PasswordMaker a for a password generator
 
Posts: 185 | Thanked: 102 times | Joined on Aug 2008
#7
Following the advice in this thread, I removed 4 resistors (13kOhms ea I think) that were bridging pins 1 and 4 to 2 and 3. I also shorted pins 2 and 3. My N9 finally recognizes my charger as a charger rather than a computer and actually charges. Hurray.




Last edited by legoman666; 2012-01-17 at 19:28.
 

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Posts: 1 | Thanked: 0 times | Joined on Apr 2012
#8
Thanks a lot for the info. I just finished modding my usb car charger. Shorted d+ and d- (no resistor) and removed the resistors connecting d+/d- to vcc and gnd. My n9 is now charging perfectly
 
Posts: 1,461 | Thanked: 1,889 times | Joined on Feb 2008 @ Edmonton, AB
#9
Did anyone ever find a pre-made cable or adapter that bridges those together on dealextreme? Something like this, but I think this won't work because samsung seems to follow the apple standard. At least my galaxy tab charges from the iphone port on my usb wall plug but doesn't charge from the standard one that the nokia n9 happily draws an amp from.
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#10
I made this kind of adapter instructions http://talk.maemo.org/showthread.php?t=83519&page=2
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