New iPad (3rd gen) weird backlight problem

[kfantasyroy]

Shot at 2012-07-28

[kfantasyroy]

Shot at 2012-07-28

[kfantasyroy]

can i direct connect left and right BL chips low parts? will short?
now is left short or right short?

[kfantasyroy]

Shot at 2012-07-28

[911us]

wow....good luck to you,find the problem yourself is hard,hope you can fix it soon

[kfantasyroy]

uptade. lcd changed same results.problem is the board

[911us]

Originally Posted by kfantasyroy

uptade. lcd changed same results.problem is the board

Is there any parts available for sale for iPad 3 ?

[Wites OM Tesla]

Originally Posted by kfantasyroy

uptade. lcd changed same results.problem is the board

Friend post scanned picture of both sides without metallic parts i will try to help you solve.

[kfantasyroy]

sorry sir ,u means i need to take out the whole board to take a clear photo?

[fs2787]

My ipad 2 has no backlight. How do you test if the backlight chip is bad. Do you check for (beep) continuity or ohm? I have 2 ohm on the backlight filter. I guessed it must be good. I also have continuity on by backlight coil, it must be good. I have no continuity on my backlight chip. Is my backlight chip bad?

[Wites OM Tesla]

Originally Posted by fs2787

My ipad 2 has no backlight. How do you test if the backlight chip is bad. Do you check for (beep) continuity or ohm? I have 2 ohm on the backlight filter. I guessed it must be good. I also have continuity on by backlight coil, it must be good. I have no continuity on my backlight chip. Is my backlight chip bad?

Here is the solution http://forum.gsmhosting.com/vbb/8532185-post102.html
To chk BL chip/diode do like this switch multimeter to diodes testing put black probe to line of diode and red probe put on other leg of diode it must show some numbers then switch probes and chk vice versa it will show nothing or 1 on multimeter this mean diode is good but if it beep show same number in both directions then is bad,i recommend to chk voltage at the filter and tell me how much it have then i will tell you what is bad.

[noobfix]

Originally Posted by kfantasyroy

Shot at 2012-07-28

what do you mean the lcd on or off?? the battery? I would just change the backlight chips. if you reallly want to test it without getting a new one, since you have two you can switch the two chips see if that reverse the problem.


like wite said we can not help and find out where the light filter is if there is the metal fame blocking the view. it is likely very close to the bl chip tho.

[fs2787]

Hello Wites. Here are my test results.

6 registors continuity test good (beep)
4R7 coil continuity test good (beep)
Backlight Diode shows 0.9 volt only in one direction. (Nothing and no beep in the other direction)
Filter shows 2 ohms. I am not sure how check for voltage on the filter since I took the logic board out of the iPad already. Here it said if the filter shows more than 2 ohm replace it. My filler shows 2 ohm. It must be good then?

I tested all the above components while they are still on the logic board. I guess some of the readings on the diode and filter could be wrong since to get an accurate reading I need to remove at least one leg to test it.
By the way, my iPad was dropped about 2 feet several times on a tile floor by my two year old son. Each time the LCD would turn off completely and I have to hold down both the power and home buttons to turn it back on. Finally I was able to turn it back on and everything works, but no backlight.

[Wites OM Tesla]

Originally Posted by fs2787

Hello Wites. Here are my test results.

6 registors continuity test good (beep)
4R7 coil continuity test good (beep)
Backlight Diode shows 0.9 volt only in one direction. (Nothing and no beep in the other direction)
Filter shows 2 ohms. I am not sure how check for voltage on the filter since I took the logic board out of the iPad already. Here it said if the filter shows more than 2 ohm replace it. My filler shows 2 ohm. It must be good then?

I tested all the above components while they are still on the logic board. I guess some of the readings on the diode and filter could be wrong since to get an accurate reading I need to remove at least one leg to test it.
By the way, my iPad was dropped about 2 feet several times on a tile floor by my two year old son. Each time the LCD would turn off completely and I have to hold down both the power and home buttons to turn it back on. Finally I was able to turn it back on and everything works, but no backlight.

Do one more test power on ipad switch multimeter at DC voltage testing hold black probe to gnd and with red chk each leg of diode tell me if voltage is same or lower on each leg,it must be around 4.7V.

[fs2787]

Originally Posted by Wites

Do one more test power on ipad switch multimeter at DC voltage testing hold black probe to gnd and with red chk each leg of diode tell me if voltage is same or lower on each leg,it must be around 4.7V.

The diode I got 4.1v on one leg and the other leg 3.7v
The filter I got around 3.4v on both legs.