no backlight! (pry damage…)

when repairing an iphone, and removing the damaged front assembly, it’s very important to be extra extra careful when removing the LCD/touch connectors.  many techs are sliding by thinking they are experienced enough to do this quickly, but as you will soon see, it would save them both some time and money to slow way down and treat this part of the repair as one of the most important parts of the job.

pry damage comparison

the above photo is a comparison between what happened and what the tech wished the phone looked like after the the LCD wouldn’t light up.  on the left side of the photo, there is an area with 2 holes in the motherboard.  on the right side is what should actually be there.  left side is after the damage occurred.  the right side of the photo is from a new phone with the part in place covered with an somewhat blackish translucent filler material.

actually, they didn’t really know what happened.  just that after the job was “finished”, and they went to turn on the phone, the LCD was very very dim.  i didn’t know what happened at first either, but after getting the board under the microscope and looking for the usual suspects, the problem surfaced.  since this filter is located so close to the area where the front assembly connectors are, my conclusion was the filter was pried off when the tech was removing the connection to make his repair.  this filter is needed for the LCD to light properly.  it’s called the backlight and this filter is located on that backlight circuit.

what is missing is a filter that is so tiny, that it can really only be seen through a microscope.  the size is .6mm by .3mm – 2/3 of a millimeter by 1/3 of a millimeter.  that is small.

backlight filter

what was also missing was the convenient pads just below that the filter was soldered to.  if that pad was still there, the job would have been finished much quicker.

i tried and tried to rebuild the pad area, but ground was very nearby and the area was just too small for what i was trying to do.  plus in removing material to try to tie into the signal below the missing pad, ground was eventually exposed in the right well area.  the circle was what i was after, but the exposed ground formed another semicircle around it.  as if to say “you can’t get to it without touching me!”  which is what kept happening.  you can see the exposed ground inside the red circle in the following photo.

ground

but i did not want to do the alternative, which was to reroute the trace.  which meant digging deeper into the phone and possibly causing another issue.  but the original plan was not happening, so we began to prepare for plan B.

plan B was to tie into the circuit at a different point.

schematic

the problem is that the different point is below one of the iphone’s soldered on metal shields.  it is never fun to remove the shield, but sometimes necessary.  you have to get the shield hot enough to melt the solder holding it on to remove it, but the components are also soldered on and also hot and with a tiny bump, you could then have a whole new issue on your hands.

fortunately i was able to remove the shield without incident and tie into the new point (a capacitor) with some new copper.  i ran the new line up to a blank area on the motherboard that seemed to be a good spot to relocate our missing filter.

building the new trace

the copper wire i’m using seems bare and to many, they would think that it would cause a short circuit to lay a bare wire across so many other points, but this is a special enamel coated wire and used by many to do just this very job.  very similar in diameter to a human hair – maybe a bit bigger.  if you are interested, maybe i will get a shot of them side by side in comparison.

i then began to try to tie into the trace at the top and found that i was able to tie into the left pad area and establish a good solid connection – great!  so i ran that line down to the blank area in preparation for the new replacement filter in it’s new location.

new trace

the green gel is a coating that will help to stabilize and protect the new trace.

i’m feeling better at this point as the repair had been quite a struggle for me.  in my mind i’m thinking i am nearing the finish, but the true test is if the problem is solved or not.  will the backlight work?  but from my research and observations, i felt i was on the right track.

so i began the last step of the soldering part of the job and mounted the new tiny filter (.6 by .3 mm) and sealed it up with more green gel coat.

FL2024 new location

time to reassemble the phone and attach a new test assembly and turn it on.

it worked!!   very exciting time.  now the customer will be happy and i can get a payday.  (oh yeah – some times a lot of work can go into a job and without any payday).

hope you enjoyed the process.

moral of the story – take great care when removing the front assembly connectors.

it works!