Ipad mini no image

[Allan]

1st gen ipad mini, comes in for "no image" repair.

Check diode on all connectors and they seem legit.
Check power getting to connector at 4.4v

Check for heat, U2200 is getting very hot. Check for short on vcc main, power switch, lampramp but none there.

Replace U2200 from donor board, still getting hot.

What am I missing?

[Jessa_the_Professa]

My comments on this are that if you have 4.4v at LCD connector for image power, then that rules out any problem with U2200---tell me why. Look at the schematic--what is the job of U2200? Why was replacing U2200 a bad idea?

If you don't have image, and you've verified that you have image power, and diode mode does not reveal any faults with image data at the connector, then it sounds like board level image is not a problem. This takes us back to rule #1. Are you sure that you are using a known good LCD for mini original? A mini retina LCD will not work, it must be a mini first gen LCD. Secondly, I'd make sure that you are actually troubleshooting a no image problem and not something else. Are you sure that this mini is detected by iTunes in normal mode? If it is auto-booting to DFU then of course it will have no image. Are you sure that you are not troubleshooting no backlight? The backlight circuit has no faults, and you can verify that you have no image and not no backlight by splitting an LCD to pull away the backlight and shine a light through from the back to see if you have image. Lastly, are you sure that this isn't the common parts issue on the digitizer with poor soldering/missing hall effect sensor, or attempting to boot the mini with no digitizer installed? The hall effect sensor is routed through the digitizer connector to the digitizer and is meant to turn off image when a smart cover is on the device. You can rule this out with a long press on the power button which should show slide to unlock.

Outside of an occasional blown image power line filter, pry damage at the connector, or water damage--- image faults in the mini just don't happen. It is always something related to parts, software, or the digitizer stuff above.

[crea2k]

Look at the schematic and diode mode test all lines for u2200 and compare to another board. If it's getting hot and you changed it already one of the lines sounds to have a small short

[Allan]

Itunes was connecting and asking for code unlock. My only thought behind replacing it was that there might have been a partial short as nothing was shorted. Why that chip was getting so hot, I wasn't sure. I looked at schematics and saw that the chip is delivering the power to the lcd so I knew it was functioning. AFter reading what you said, i took apart another mini to get known good parts. Apparently the stack of 7 lcd's i have, had no image and were dead. Seems to work fine with good parts. Throwing some things away....

[Jessa_the_Professa]

Make sure you recognize the difference between ipad mini 1st gen LCD and mini retina LCD. They cannot be swapped. I would think it is more likely that 7 LCDs are the wrong one for the device rather than 7 LCDs are bad. Check on the back of the LCD--the tiny flex on the mini original LCD comes around the side. The tiny flex on the retina LCDs comes up from the bottom.