Hot Air repair, what temperature?

Hi @refurbpro

Great info, thank You!

I was considering leaving the board in the phone since I watched a hot air video of that last night and it was successful. But your point about cable damage makes sense and I really do not want that. I will sharpen my soldering iron tip (my initial preferred method for this anyway) and practice on a bad iPhone 5 .

If I short across the filter pads will it cause noise to show on the screen? I thought about trying that.

It's a great idea to practice before trying the real thing. Not everyone gets that opportunity! From my experience, the short fix doesn't cause any kind of back-light noise (I've done that fix at least 5 times).

I can say that it is much easier to do the filter fix with hot air as you are working with two microscopic solder pads... but it comes with the process of taking the board out of the phone.

One more side note: if you have any type of solder flux, its worth putting a drop on the filter before applying heat. This will make the whole repair a lot easier.

Jeff:

After practicing my soldering some I decided to just try the jumping of where the filter would go on the motherboard. I used a small piece of #40 wire and was careful not to cause a short. After soldering the wire I tested the backlight line going to the connector and it showed continuity. I placed the positive probe on a ground and the negative probe to the backlight line of the connector and it read about 0.5 ohms, what I read it should be for the backlight diode. I connected the display and battery, the backlight came on dimly for a moment then went off. The area of the connectors AND where the backlight circuit is under the CPU shield got very warm quickly. I disconnected everything, verified no shorts, and tried it again. Same result. I disconnected the display and removed the jumper from the filter location, then reinstalled the display. As before, I tested the display function using a flashlight and it is working.

I Tested B+/Gnd for shorts- any suggestions appreciated!

Thanks!

Is it possible to test for the backlight voltage (about 18 volts) if I remove the display and turn it on? Would this help?

It is possible to test for the backlight voltage. This can be done by putting one probe on any grounded (shield) part of the board and touching the positive probe to any one of the backlight pins on the LCD connector.

Check closely around the connector for any type of possible short or pin damage as this jumper will remove the ability for a fuse to blow if high amps flow through the connector again. If these issues continue and you cannot verify that the solid 18-20v is coming through the backlight pins, there might be additional problems with the backlight circuit.