Fix Your Stuff Community Store

Released September 16, 2016. Model 1660, 1778 Available as GSM or CDMA / 32, 128 or 256 GB / Rose gold, gold, silver, black, and jet black.

2264 Questions View all

Options

Working backlight but no image

I have a phone for repair it came in as no image problem with no backlight.

After checking the phone, a capacitor for the backlight, C3903, was missing. Instead of replacing it, I bridged it together which was wrong choice because it burned the backlight filter FL3901 off the trace. So after replacing the capacitor C3903 I made a jumper and connected it to C3725, enabling the backlight to turn on. Now the problem is image. I don't know where to start looking for the problem. Any response will be appreciated.

Answered! View the answer I have this problem too

Is this a good question?

Yes No
Score 0
Add a comment

1 Answer

Filter by:
Most Helpful Newest Oldest
Chosen Solution

Options

C3903 is a NOSTUFF component, meaning it's not placed on the logic board. It's in the schematic though and was probably used for development/testing purposes. So there is no need to replace it. The other thing is that you NEVER EVER bridge/short the contacts for a capacitor...that's not how capacitors work. So you basically forced the output of PP_LCM_BL_ANODE to ground and blew the filter FL3901. Are you certain the backlight works?

As for the LCD, this is the circuit you need to troubleshoot. Check for shorts on the outputs and then check for proper voltages.

Block Image

And check the filters...

Block Image

Was this answer helpful?

Yes No
Score 2
Add a comment

Add your answer

Sarbear will be eternally grateful.
View Statistics:

Past 24 Hours: 0

Past 7 Days: 1

Past 30 Days: 2

All Time: 1,501