RAZR V3 will not charge by simply supplying 5V through USB (it's possible to use common USB cable for charging if you are using Motorola special PC driver software).
Motorola uses the pin between Pin #3 and #4 (Pin X) to sense what device is attached to the mini-USB port. Shorting Pin #3 to #2 and #X causes the phone to go into handsfree/carkit mode and the LCD backlight will ignore timeout settings and stay on.
Shorting pin X to pin 2 and to pin 4 via R=200KOhm causes the phone to go into charge mode.
MOTORIZR Z6tv - In Order to make your PC charge your phone through a usb cable w/o installing any special drivers or software: Short pins 2 and 3, then put a 200K Ohm resistor between pins X and 4.
- The phone supplies ~2.14Vdc to pin X before anything is plugged into it. It needs to be dropped 1V to approx 1.16Vdc. Putting a 200K Ohm resistor between Pins X and 4 will bring that voltage down to around 1.16Vdc.
- The wall charger has pins 2 and 3 shorted together. Not sure if it's a safe practice shorting the USB DATA lines together on your PC, so do at your own risk. However, it does work on my terminal with out any ill effects.
| AC adapter Pin |
Name | Direction | Description |
|---|---|---|---|
| 1 | +5 VDC | -?- | PC USB Pin 1 (+5 VDC). |
| 2 | USB Data | -?- | shorted to pin x in charger cable. |
| 3 | USB Data | -?- | not connected |
| X | -?- | Shorted to pin 2 + shorted to pin 4 via R=200KOhm in charge cable. (R=165KOhm?) | |
| 4 | GND | -?- | PC USB pin 4 (GND). Shorted to pin X via R=200KOhm in charge cable. (R=165KOhm?) |
A standard Motorola USB charger puts ~1.4vdc onto the x pin of the mini USB plug. A 200k resistor between pin 2 and 4 produces ~1.9vdc on the x pin. This works for Motorola Q (which works from ~1.2vdc to ~1.9vdc), but not for Razr V3m. I had to lower the resistor to 165k. This produces ~1.5vdc and allows the charger to become authorized.
After many trial and error, the working pinout for my RAZR V3C was to short 2 and 3 THEN Short X and Gnd with a 200KOhm resistor. Work good on my unbranded USB car charger and with a PC without any driver installed.
Comment by Eric
Andre's schematic also works for the motorola IC502. I used a 220kohm resistor(that's what I had laying around). Thanks Andre.
Comment by kaputnik
Andre's schematic also works for the V3x. According to the spec sheet for the Enhanced Mini USB interface circuit, shorting pin 2 to pin 3 (the data lines) and putting a resistor of 200kOhm on the ID pin x to pin GND will put the phone into "Dumb Mid-Rate Charger (500mA)" mode with 1.225 volts on pin x. Putting a 440kOhm resistor on pin x to pin GND will put the phone into "Dumb Fast Charger (1.25A)" mode with 1.68 volts on pin x.
Comment by Alex
I just broke my RAZR V3i original car charger and it have the following: 1 +5V, 2 shortened to 3, X goes to GND via 440kOhm.
Comment by Tom Maneiro
I have tested with a 260K resistor (i only had these in this range) with a standard Motorola wall-wart charger (the MiniUSB plug on it was broken), and it works with V3c, V3m, U6, U6c... but not with my K1m (it only says "Unable to charge").