Revamped version of the iPhone 3G with faster processing speeds. Repair of this device is similar to the 3G, and requires simple screwdrivers and prying tools. Model A1303 / 16 or 32 GB capacity / black or white plastic back.

1959 Questions View all

Not booting up - dead logic board?


I got a broken iPhone from a friend, who dropped it into water. After that backlight wasn't working, so he tried to change a coil as shown

here. After fixing up some soldering and cleaning off the flux with acetone, I closed it up and attached it to a charger. The phone showed some life signs (battery charge screen), I left it there a couple of minutes, but now the screen is completely black, and it is not recognized by iTunes.

I have access to a small electronics lab, so measurements are not a problem, the thing is, how can I test if the logic board's alive? Are there any test pins I can check?


Answered! View the answer I have this problem too

Is this a good question?

Score 0
Add a comment
Spread Fixmas Cheer
Get $12 off your purchase of $50 or more with code FIXMAS12
Spread Fixmas Cheer
Get $12 off your purchase of $50 or more with code FIXMAS12

1 Answer

Chosen Solution

g5pw, I would start with checking the dock connector as well as the battery. Check the voltage on the battery connectors and see what you get with your dock connector plugged in. My concern would be that someone else already did a solder job on it. The first thing I would definitely do, is to clean the logic board with isopropyl alcohol. Use this guide to clean your phone. It was written for a 3G but most certainly applies to yours as well. Make sure that all connectors and cables are free of any corrosion/debris. If you do not get the appropriate voltage from the charger, check the fuses to make sure they are working okay. Oh, and do not forget to replace the battery, especially since it may have had water damage. The iDevices batteries do not like any kind of liquid exposure. Check the attached image for some of the voltages for you to check. Hope this helps, good luck.

Block Image

Block Image

Was this answer helpful?

Score 1


Just what I needed, thanks! Battery voltage was 2.7V (the device was in storage for quite some time), I left it to charge overnight, and this morning it was warm, I'll reopen the case and check, and I'll check all the testpoints, too!


So, I checked the test pins, and got 0.3 V Vddsd1 and 2, but after an overnight charge I suspect the battery is dead. Open terminal voltage of 2.3V Strongly suggests so. Off to buy a new bettery!


Add a comment

Add your answer

g5pw will be eternally grateful.
View Statistics:

Past 24 Hours: 0

Past 7 Days: 0

Past 30 Days: 1

All Time: 4,230