Hello,
I recently acquired an XDA 2 with broken terminal. I soldered a new terminal to it. It is synchronizing fine and charging from USB but it is not charging from main or car charger. Apparenlty all solders are OK and pinout are as they should be (accoring to other postings on this forum). Pins 20, 21, 22 are showing connectivity among themselves and to positive terminal of standard charger. Pins 16, 17 and 18 showing connectivity among themselves and to ground (and negative termial of charger adaptor).
I used more than one chargers and checked voltage. Everything seems OK.
Any idea where the problem may be?
Thanks for assistance.
If it's charging via mini-USB, you need a charging cable when charging from a non-data source. These differ from normal USB cables in so much as they have pins 4-5 shorted together.
As an alternative, try resetting the phone with the cable plugged in. Sometimes this is enough to false the circuit to initiate the charging sequence. This emulates what happens when charging via a PC's USB port.
hey
i have a broken conector two!But i am from romania and i can't find here to buy! how muxh was it?
http://forum.xda-developers.com/showthread.php?t=310441&highlight=himalaya+connector
this guy would know where you can get the connector and what it's partnr is
andreibbc said:
i have a broken conector two!But i am from romania and i can't find here to buy! how muxh was it?
Click to expand...
Click to collapse
Hi andreibbc,
I took the connector out of an XDA (with broken screen!). You may buy new replacement from ebay (see item number 260138794518) but it will require good soldering skills!
liquidsilver said:
If it's charging via mini-USB, you need a charging cable when charging from a non-data source. These differ from normal USB cables in so much as they have pins 4-5 shorted together.
As an alternative, try resetting the phone with the cable plugged in. Sometimes this is enough to false the circuit to initiate the charging sequence. This emulates what happens when charging via a PC's USB port.
Click to expand...
Click to collapse
liquidsilver, thanks for your prompt response.
By mini-USB do you mean some special connector? I do not see any mini USB connector in the phone itself. It is charging through sync. cradle using usb connection, irrespective of whether main charger is connected or not. If I remove usb connection from computer it stops charging.
Please advise how to reset the phone with cable plugged in? (I assume you are referring to standard main charging connector)
http://forum.xda-developers.com/showthread.php?t=242772&highlight=connector
this guide show how to put in a miniUSB connector to replace the
org buttom connector of the devices
Rudegar said:
http://forum.xda-developers.com/showthread.php?t=242772&highlight=connector
this guide show how to put in a miniUSB connector to replace the
org buttom connector of the devices
Click to expand...
Click to collapse
Thanks for your response.
Since original connector (after resoldering) is working fine except main charging, I would rather keep it.
I would prefer trying options that will keep the existing connector such as resetting phone (as suggested by some other member, how?) or finding the actual cause of problem (including short connectors)
Any assistance will be of help?
i'm not 100% sure what your issue is
if the device is no charging
the most plausble reason is
broken legs on the connector
or bad solvering to the pcb for the chargning pins
or wrong connections
http://wiki.xda-developers.com/index.php?pagename=Connectors
Rudegar said:
i'm not 100% sure what your issue is
if the device is no charging
the most plausble reason is
broken legs on the connector
or bad solvering to the pcb for the chargning pins
or wrong connections
http://wiki.xda-developers.com/index.php?pagename=Connectors
Click to expand...
Click to collapse
Let me restate the problem.
I got an XDA II with broken connector. I took connector from and XDA (all legs intact) and soldered it to XDA II. Apparently soldering is fine.
The set is now synchronizing fine and charging while synchronizing (through USB and not through main charger). If I remove USB from computer it stops charging even if the main charger remain connected to synchronizing dock.
As long as direct main charging or charging through car adaptor is concern, Pins 20, 21, 22 are showing connectivity among themselves and to positive terminal of standard charger and Pins 16, 17, 18 showing connectivity among themselves and to ground (and negative termial of charger adaptor). If I am not wrong these are two sets of pins that are needed to be connected for main charging. I have checked main adaptor and tried more than one adaptors with same result.
My questions are:
Is there any other pin that may be short (or not connected) that is causing main charging to fail?
Is there any other possible component failure and if yes, which one and how to check it?
If the main charging has some programming part associated with it, is it possible that a reset may restart charging? if yes, how?
I hope the problem is clear now.
Thanks for your assistance.
msu said:
Let me restate the problem.
I got an XDA II with broken connector. I took connector from and XDA (all legs intact) and soldered it to XDA II. Apparently soldering is fine.
The set is now synchronizing fine and charging while synchronizing (through USB and not through main charger). If I remove USB from computer it stops charging even if the main charger remain connected to synchronizing dock.
As long as direct main charging or charging through car adaptor is concern, Pins 20, 21, 22 are showing connectivity among themselves and to positive terminal of standard charger and Pins 16, 17, 18 showing connectivity among themselves and to ground (and negative termial of charger adaptor). If I am not wrong these are two sets of pins that are needed to be connected for main charging. I have checked main adaptor and tried more than one adaptors with same result.
My questions are:
Is there any other pin that may be short (or not connected) that is causing main charging to fail?
Is there any other possible component failure and if yes, which one and how to check it?
If the main charging has some programming part associated with it, is it possible that a reset may restart charging? if yes, how?
I hope the problem is clear now.
Thanks for your assistance.
Click to expand...
Click to collapse
Forgot to mention one thing which is that Pin 2, which according to connector diagram should be ground/ sensing is not showing connectivity with ground or with Pins 16, 17 , 18.
Does it affect main charging? and should I ground it?
Thanks
Related
Is there a fix for the USB (no)charge bug??
Are you using an xda1 usb cable?
I'm using the BoxWave miniSync, it says "xda" on it, but BoxWave who sold it to me as an adaptor for the XDA II say it's the same, they also sent me the following email today:
"We are aware of the issue, and it is not a problem with the miniSync as you
may suspect. The O2/XDA II has a software bug the prevents charging from
low current sources, such as USB. If you have a unit that has the
attribute, you should contact HTC or the brand which your XDA II is made by
and request the bug fix.
The problem does not exist in every XDA II, which is why HTC did not make a
public announcement regarding the bug. We have done in-house testing to
confirm this, as our wiring structure is identical to the stock connection,
with the only difference being the incoming power current levels."
I've got one's, wried as :
+5v -> pin22
UDC+ -> pin 14
UDC- -> pin 15
GND -> pin 18
it can sync on XDA II, but can't charge when battery less than ~60% from USB port (more battery is ok).
Do I have to change GND to another pin to force my XDA II charge?
I've got one's, wried as :
+5v -> pin22
UDC+ -> pin 14
UDC- -> pin 15
GND -> pin 18
it can sync on XDA II, but can't charge when battery less than 60%, more battery is ok.
Do I have to chang GND to another pin to make my XDA II charge on USB port
I have tried the usb charging on 2 pc's. On the first one it started charging very slowly then basically stopped charging as I used the device.
On the second machine it charged very well regardless of whether i was using it or not. I was also activesyncing on the second machine.
I bought the Pocket PC Tech's Lil Syn, which is very similar to the BoxWave product, and the USB sync/charger drained my battery.
I read BowWaves response that only some MDA2 or XDA II have a problem with this, but what I find interesting is that I can charge via USB on the cradle regardless of how low my battery is, but I seem to have issue with the Lil Sync product.
Why would this be? Is the cradle more powerful than the PPC Tech or Boxwave products? That does not seem likely.
It seems if the cradle does charge, but these other products do not, then the problem would not lie with the PPC Phone-2003.
USB Sync & Charge cable.
Okay.. I was a little Pissed when my cable wasn't working, so I started looking into the differences and found that ground was going to Pin2 on my sync and charge cable, where my stand alone charger didn't have that. So I snipped the wire that went to pin 2 and walla, it charges now.
I still am having problems getting my battery pack to work. It's a pack that takes 4 AA's and is supposed to charge it too. It supplies more Volts than the USB, but it won't start the charging process. I'm going to try and wire it more simpler to my USB Sync/Charge cable and see what happens.
Let me know if this helps,
Brandon
USB Sync & Charge cable.
Okay.. I was a little Pissed when my cable wasn't working, so I started looking into the differences and found that ground was going to Pin2 on my sync and charge cable, where my stand alone charger didn't have that. So I snipped the wire that went to pin 2 and walla, it charges now.
I still am having problems getting my battery pack to work. It's a pack that takes 4 AA's and is supposed to charge it too. It supplies more Volts than the USB, but it won't start the charging process. I'm going to try and wire it more simpler to my USB Sync/Charge cable and see what happens.
Let me know if this helps,
Brandon
as ive replied saying on other posts......
XDA 2 charger kicks out 2Amp max XDA only does 1amp max
most charging assesories are XDA 1 compatible only yet people say they work on the xda 2 means they have found out they plug in simple but they dont kick out more then 1amp as usb ports can only handle 1amp max.
thats why it doesnt charge it might charge if you turn your device off and disbale activesync from waking the device up but it will take twice aslong to fuilly charge maybee longer but if the device is awake youll find that the device is using up more power then the usb charger can give out so in otherwords your device will die instead of charging itself up.
gaz
I have a standard xda1 sync/charge cable and it charges my xda2 regardless of the amount of charge left in the battery, and it does it very quickly too, I think it is a bug in some of the xda2 machines.
Re: USB Sync & Charge cable.
NeoCole said:
Okay.. I was a little Pissed when my cable wasn't working, so I started looking into the differences and found that ground was going to Pin2 on my sync and charge cable, where my stand alone charger didn't have that. So I snipped the wire that went to pin 2 and walla, it charges now.
I still am having problems getting my battery pack to work. It's a pack that takes 4 AA's and is supposed to charge it too. It supplies more Volts than the USB, but it won't start the charging process. I'm going to try and wire it more simpler to my USB Sync/Charge cable and see what happens.
Let me know if this helps,
Brandon
Click to expand...
Click to collapse
Hi: can you provide your pin configuration for continuous charging while idle or being used.
I have this adapter that came with my xda2, is the wiring correct for use in a car adapter charging? Thanks.
mdbusa_2000 said:
I have tried the usb charging on 2 pc's. On the first one it started charging very slowly then basically stopped charging as I used the device.
On the second machine it charged very well regardless of whether i was using it or not. I was also activesyncing on the second machine.
Click to expand...
Click to collapse
do you have a pin config for your second m/c. Thanks.
Further to my earlier post, my xda2 now no longer charges from the usb sync/charge when the xda2 is low on battery, this only happened since I got my first "low battery" warning, I put it on charge, looked a few minutes later and it had gone from 10% to 7% battery power.
Hi all, pls look at this post... the non-charge issue can be addressed... http://forum.xda-developers.com/viewtopic.php?t=5438
Best regards,
Hi,
I currently repair XDA Exec's for a client of mine who use them for their delivery drivers. They are constantly breaking the screens which are easy to fix, but more often than not they smash off the usb connector and leave it rattling around inside. This is not usually a big problem to fix unless the pads that the 5 pins are soldered to have been ripped off the board. I have found that even if I successfully replace the connector with a new one and solder the two outside pins (which are the gnd and 5v pins) the battery will not charge. The puzzling thing is, if I remove the battery, the red led comes on, presumably indicating power to the device. As soon as I connect the battery the led goes out and the unit boots up only to reveal that it is not charging. So I'm presuming two things:
1. There is some other electronic component damage in the unit caused when the connector broke (due to it being on the end of the charger cable at the time, if this is the case I will scrap the unit)
2. There is some feedback from the battery that the charger needs to continue with it's output and because I didn't reconnect the data pins it won't charge.
Does anyone know how the charging circuit works and what pin / connections are required for charging. I guess the same principle will apply to many PDA's & mobile phones.
Thanks
Rick
http://wiki.xda-developers.com/index.php?pagename=HTC Universal Service Manual
http://pinouts.ru/Slots/USB_pinout.shtml
mini usb is a standart anyway
.Lemon
Hi,
Thanks for your reply, call me a lemon but what utility do I need to unpack a .lemon file ?
Rick
Lemon Head
Forget that last post ok...
hi guys, I soldered a 5v charger's +5v & ground wires to a female USB port, then connected to the mini-usb port of the Atom, external power was detected but it doesn't charge, what else do I have to do to trigger charging? thanks!
ashy said:
hi guys, I soldered a 5v charger's +5v & ground wires to a female USB port, then connected to the mini-usb port of the Atom, external power was detected but it doesn't charge, what else do I have to do to trigger charging? thanks!
Click to expand...
Click to collapse
Interesting. I've noted similar issues, I first thought it was to do with the power current capacity however I'm not so sure now. What I did find was that if I plugged in the usb plug first and then turned the charger power on (e.g. car charger 850mA) then it would charge. However the original charger worked any which way. Also turning off the screen would result in slow charging even when it said not! Does this help?
There is some problem in oem battry driver, you can google to find the driver hotfix.
sorry for my BAD english..
You must give two other pins short with resistor as i remember. This is in order to simulate USB connectivity, which original charger do.
This is for HP Ipaq rw6815 I have..
more info you can find in below links it's for other devices, but the workaround is the same:
http://ecece.com/info/ipaqcradlemod/ipaqcradlemod.html
I don't think below method i safe enough, I think it's not a wise decision to shorten your data pins, but obviously work with iphone
http://carlhutzler.com/blog/2009/07/28/usb-hub-as-an-ipodiphone-charger/
Hi. I've solved the problem of using other chargers with GT.
Like Apple, Samsung used a little trick with their chargers.
To charge your GT with any usb charger you have to make a little adapter.
Usb pinout:
gnd d- d+ 5v
To work you must short d+ and d-.
From 5v use a 33k resistor to d+/d-.
From gnd use a 10k resistor to d+/d-.
If you have multimeter you should obtain ~4v between 5v and d+/d-; and ~1v between gnd and d+/d-.
I tested it and it's working.
Hi, it's not a trick but a standard. You only need to short d+ with d-, the resistors are not needed. Just be sure that the charger outputs closest to 5v possible, around 5.2~3 usually work for everything. About 5.6v and it start not to work on some devices, like apple..
Maybe, I have to test that
I know it's not a trick, I should wrote "trick".
For example GT adapter outputs 5.31v.
Apple adapter worked with 1 22k resistor between d- d+.
WarlockM said:
Hi. I've solved the problem of using other chargers with GT.
Like Apple, Samsung used a little trick with their chargers.
To charge your GT with any usb charger you have to make a little adapter.
Usb pinout:
gnd d- d+ 5v
To work you must short d+ and d-.
From 5v use a 33k resistor to d+/d-.
From gnd use a 10k resistor to d+/d-.
If you have multimeter you should obtain ~4v between 5v and d+/d-; and ~1v between gnd and d+/d-.
I tested it and it's working.
Click to expand...
Click to collapse
WarlockM said:
To charge your GT with any usb charger you have to make a little adapter.
Click to expand...
Click to collapse
How can you do that? You need an extra device adapter? Please explain.
I've tested with d-/d+ shorted and it's not working.
@MizGarfield if u have 1 usb extension cable u can cut it on half.
Tie together white and green wires.
Tie black wires and conected to that 1 end of 10kohm resistor, the other end tie it to green/white wire.
Same to red wires but use 33kohm resistor.
See att. Sry for drawing.
bookmarking this for later use
WarlockM said:
I've tested with d-/d+ shorted and it's not working.
@MizGarfield if u have 1 usb extension cable u can cut it on half.
Tie together white and green wires.
Tie black wires and conected to that 1 end of 10kohm resistor, the other end tie it to green/white wire.
Same to red wires but use 33kohm resistor.
See att. Sry for drawing.
Click to expand...
Click to collapse
You don't need that for modern devices has i told you. It did not work because you did it wrong. I have all my usb chargers working the new way, you even have wikipedia talking about it. You have to cut the data + and - on the power supply from the female usb port and short only the female d+ and d-. Trust me it works and it is alot simpler.
Edit : from wikipedia "The Dedicated Charging Port shorts the D+ and D- pins with a resistance of at most 200 Ω. The short disables data transfer, but allows devices to detect the Dedicated Charging Port and allows very simple, high current chargers to be manufactured. The increased current (faster, 9 W charging) will occur once both the host/hub and devices support the new charging specification."
""As of June 14, 2007, all new mobile phones applying for a license in China are required to use the USB port as a power port.[35][36] This was the first standard to use the convention of shorting D+ and D-.[37]""
http://apple.slashdot.org/story/10/08/03/1743240/Hardware-Hackers-Reveal-Apples-Charger-Secrets
""We all love to call out Apple when they design deliberate incompatibility into their devices, but there is a perfectly valid technical reason for what Apple is doing here, and, in fact, they are following a USB specification (which LadyAda unfortunaterly didn't even test).
Without data communications or when suspended, devices may legally draw no more than 2.5mA from a host, which is useless for charging. In fact, even if you're generous and pretend they're connected, devices are not allowed to draw more than 100mA without negotiating for a higher current, which requires actually talking to the host, and 100mA is still too little to charge properly. 500mA is the maximum allowed by the USB spec, but devices must negotiate it (there may be too many devices on the bus for negotiation to succeed).
Before there was a spec for "dumb" USB chargers, Apple used the resistors as a sentinel to avoid drawing too much current from undersized chargers in order to avoid damaging the host. This is a hack, but it works, and honestly, we're smart enough to figure out a couple resistors on the data lines. It's not like they're using crypto auth on the charger. They have a perfectly valid reason to do this. Devices which charge from "dumb" chargers aren't following the spec, though this is a common industry practice.
As it turns out, the USB-IF came up with a USB Battery Charging spec [usb.org]. The spec is long and boring, but it boils down to: short together the data lines (no resistors required) and you indicate that you're a dumb charger that can supply anywhere from 0.5A to 1.5A.
Guess what happens when you short the data lines of an iPhone 3G and supply 5V [marcansoft.com]. Did Apple just follow a standard? Incredible!
(Yes, I'm not following the USB spec there by in turn using a USB cable to supply the 5V and not negotiating over its data lines. I didn't feel like grabbing a dedicated 5V PSU for the shot, so sue me.)"""
http://marcansoft.com/transf/iphonechg.jpg
ok ??? no need for resistors, only 5.3V MAX and d+ and d- shorted
Thnx for the tip gonna try this later on my sanyo eneloop power booster tried it yesterday without this mod and it doesn't charge so gonna look for a AF to AF converter and modify it to gound the D+ and D-
@adolfotregosa
I tried again shorting d-d+, with iphone it works but with GT it's not working.
I use BatteryWatch and it is saying Not Charging. It's detecting the connection like usb port but is not. I use some device build by myself with 1 amp capabilities. D- and D+ r free of any connection and i can do with them what i want.
I dont say you r wrong but it's not working with GT.
Sent from my GT-P1000 using XDA App
but smt is wrong on your custom setup, voltage ??
EDIT: i just measure the original charger and it has no resistance between the data and power pins.
I think i know what could be wrong, when you plug in the Tab and it says not charging, how many volts have you got at that time ?
The original charger is very good because when it not charging the tab it has 5.3x volts but when you plug it in it lowers to 4.8x V Max and that is very good ! most chargers tend to lower much more (bad quality or just not powerful enough) and that is what causes the not charging messages on the tab or other devices.
Well i rest my case on this.
My device with no load it have 5.21v and with load 5.03v so it's not from him and i have another supply 5v/12 amp and it's doing the same (not charging, only with data shorted).
When u r trying to measure the original ps u can read ~7k between gnd and data but from 5v to data u cant because it have some capacitors.
Maybe samsund did something else, i have to try, maybe data pins drawing some current (mA) and that's why it's not working with only shorting them.
For the moment it's the only (working) solution i've found and i'm happy with it .
P.S. If i'm not finding anything else the last resort will be to open the original ps
Sent from my GT-P1000 using XDA App
USB Charger
This is what worked for me.
Items Needed:
USB Extension Cable
33k-Ohm Resistor (Shack Part No. 271-1129)
10k-Ohm Resistor (Shack Part No. 271-006)
Steps:
1. Cut USB Extension Cable in half, lets name the 2 halves, the half you will plug into the power suppy will be called "Cable A" and the half that you plug into the Galaxy Tab Data Cable will be called "Cable B"
2. On 'Cable A" strip outer plastic to expose all wires within, eliminate Green and White on this cable only as it will not be needed, leaving you with only the Red and the Black Cables
3. On "Cable B" strip outer plastic to expose all wires within, this should leave you exposing all 4 wires
4. On "Cable B" strip both the Green and White wires and join thes 2 wires with the 2 resistor ends (you should be using the resistor ends that have the red band with these wires), these can be joined by either soldering or just twisting together.
5. Strip Red wire from both cables and join together with the 33k-Ohm Resister (this will be the larger of the 2 resistors and should also be the end with the Gold Band) and as well join these together with solder or just twisting together.
6. Repeat the above process with the Black wires and 10K-Ohm Resistor.
7. No finally use Electrical Tape or Shrink Tubing to cover all your work.
This worked using it on a Champtek 5v 2.1a USB Car Charger and Home Charger. Also worked with iPhone charger. Also works with Original Galaxy Tab.
Hope this helps out.
May I just ask some clarifying questions?
rick75204 said:
This is what worked for me.
...
4. On "Cable B" strip both the Green and White wires and join thes 2 wires with the 2 resistor ends (you should be using the resistor ends that have the red band with these wires), these can be joined by either soldering or just twisting together.
Click to expand...
Click to collapse
Does it matter WHICH resistor you join to which of these two wires?
rick75204 said:
5. Strip Red wire from both cables and join together with the 33k-Ohm Resister (this will be the larger of the 2 resistors and should also be the end with the Gold Band) and as well join these together with solder or just twisting together.
Click to expand...
Click to collapse
So that you have effectively bridged the red wire with 30K-Ohms to one of either green or white running to the TAB?
rick75204 said:
6. Repeat the above process with the Black wires and 10K-Ohm Resistor.
Click to expand...
Click to collapse
And bridged the black wire with 10K-Ohms to the other of either green or white running to the TAB?
Would this be an accurate picture, with the 33K Ohm Resistor on the left, and the 10K Ohm Resistor on the right?
I think the intention was that you short the green and white wires together: so you are connecting both wires to both resistors.
That way the two data lines are both held at a fixed voltage of about 1.2V
Thanks, that clarified it.
I noticed today that if I connect my Tab to my keyboard (standard Apple USB KB with keypad, connected to a circa 2006 iMac), the device started charging according to battery stats. When it was plugged in it was at 48% and it ended up at around 60% after a few hours. Am I being deceived or something? I was under the impression that it would only charge if connected to the mains charger. Well I guess I'll see how long it runs now it's off the leash and see if it lasts till the morning (left my charging cable at work - D'oh!).
No, it definitely does charge even when it says it isn't - just slowly. I've got a 2A non-official USB charger that charges it up pretty quick, but still says it isn't charging. If the screen is off, it will even charge off one of those tiny Kindle chargers that must be delivering less than 500mA, but *really* slowly.
Clarify
Sorry guys, only a clarification.
As far as i understood:
the GT DOES charge with *any* charger (or connection to PC);
if you use the original charger (2Amp), it charges showing the charging-icon;
if you use a non-original charger, it charges in any case but NOT showing the charging-icon and depending on the charger power (even 1Amp charges, or 500mAmp, *VERY-REALLY* slowly);
if you use a non-original charger with the two resistors (33k + 10k) it charges showing the icon (even with a 1Amp).
Can anybody confirm if i understood well?
Thanks!!
eiem said:
Sorry guys, only a clarification.
As far as i understood:
the GT DOES charge with *any* charger (or connection to PC); Yes but slower than the original charger
if you use the original charger (2Amp), it charges showing the charging-icon; Yes, exactly
if you use a non-original charger, it charges in any case but NOT showing the charging-icon and depending on the charger power (even 1Amp charges, or 500mAmp, *VERY-REALLY* slowly); Yes.
if you use a non-original charger with the two resistors (33k + 10k) it charges showing the icon (even with a 1Amp). Depends, i get various results even though i am using the mod since day 1.
Can anybody confirm if i understood well?
Thanks!!
Click to expand...
Click to collapse
Thats it for now.
It seems that the Tab could recognize the status of the usb connection by measuring the usb data rx/tx wire level. If it is not shorted, the "pluged in but not in charging" status will appear, as the mismatch voltage of the usb connection is made.
Sent from my XT701 using XDA App
I recently bought a custom 2 amp charger after the stock one died. Anyways, whenever I plug it in, I noticed that it would ask me whether I wanted to access the USB storage. Apps that need the SD card similarly, would terminate (ex: music).
Is there any way to solve this and to make the phone realize that this is a power outlet charger and not a USB charger? I think that the Epic drew about 650 milliamps or so charging and much smaller over PC (I think about 350 to 400 ish IIRC). It seems to currently only be charging at PC USB speeds as well and not the same rate as the stock charger.
Thanks in advance.
There's a way for the phone to tell if it's connected to a PC or AC adapter depending on a resistor shorting out two pins. Make sure you don't have anything other than the +5V and Ground connected.
I had the same thing happen with a car charger. Bridging / shorting the data pins causes the Epic to see the charger as a regular charger, and not usb for data or charging. This can also be done in the cable, itself, however, then you have the problem of having to cut part of your USB cable and re-tape or heat-shrink tube it.
There's a couple threads discussing similar problems/solutions:
http://forum.xda-developers.com/showthread.php?t=908363
http://forum.xda-developers.com/showthread.php?t=709226