Chris Stables

Making up some leads for the DCPS and would like to know does the MacBook determine what wattage magsafe it is using from...

I don’t know a lot about MacBook circuitry and I don’t advertise their repairs but there is one customer who does send...

Any idea where I could purchase a QFN8 to DIP8 Adapter that will fit a bios chip off the 820 00875 board. The only one I...

I got sent a mac which had the U5860 temp sensor torn off along with all the pads on the board. It would take ages to boot...

Would someone be able to tell me the orientation position of U5860 on the 820-00239 logic board. I can only make out a...

If you removed the screen but did not remove the home button the problem will be a micro tear in the flex coming from the screen to the logic board. It will be on the shortest flex at the 90 degree bend. You will need a replacement screen.

Changing the serial number to the original one will have no effect. You also need to transfer the flex assembly from the original battery as that is where the chip is that is linked to the phone. You need special equipment for this procedure like a micro spot welder and micro soldering iron.

The most common cause for home button failures on the 7 series is a micro tear in the flex coming from the screen to the logic board. You will need to get a replacement screen.  If it is still not working you will need to purchase a “universal home button” it will bring back everything but fingerprint ID.

We never suspect a board issue until we have ruled out parts. I know you have tried everything possible with what you have on hand but you will need to completely rule out a faulty part. We would usually put the logic board into a known good housing to rule out parts but you can try. 1.       Different charge cable. 2.       Different PC or Mac 3.       Disconnect all the flex cables except for the battery and charge port and see if you can restore. Other than that you will need to install a new battery and charge port. You said using 3uTools which is a good program that it goes from recovery to normal mode and hangs on the apple logo and status bar, this would point me in the direction of a parts problem and not a board problem. However I have not run into this on the 11 series before as they are fairly new so I could be wrong.

Check if you can read the NAND. If you can get it into DFU you could use the iBox but it is a more certain conformation if you remove it and use a programmer.

You will need to address the liquid damage by removing the screen and checking where the liquid went. There are three sections to the home button. 1.       The home button assembly which has other components on it besides the home button. 2.       The flex cable the home button connects to which is integrated into the screen with two flex cables. 3.       The connector on the logic board. You can try cleaning the components on the home button assembly with some 99% isopropyl alcohol and a Q tip. I would also check the logic board for signs of liquid if you see any I would remove the board from the housing and swish it around in the alcohol. If none of the above brings back your home button you will need to try a replacement screen. If the replacement screen doesn’t work you will need to purchase a Universal home button or take it to the apple store to get a replacement screen and home button.

If you brought a non-working phone from eBay you will have to assume it will not be an easy repair as the seller probably has had some one already look at it and since it is a new model makes it even harder. I would at least try another battery but I don’t think that will be the problem as your amp reading would point me to a short on the logic board or part connected to the board. You could start by disconnecting all the flex cables except for the battery, charge port and see if your PC will recognise it. You will probably need to put it in recovery or DFU mode for it to be recognised. If that doesn’t work. ·         You will need to completely rule out parts by installing the logic board into a known good housing with a charged battery. ·         If it still will not boot you will need to start checking power rails. The first line to check would be VDD_MAIN followed by the NAND power rails, this will be tricky if you are not an experienced repairer as there are no schematics for the 12 Max pro yet. You...

Did you have the battery disconnected before removing and replacing the screen? It sounds like you have damaged the backlight circuit. See if your PC recognises it and shine a torch on the screen to see if there is an image there. This is one model of the iPhone that you cannot disconnect the screen without disconnecting the battery. If it is the backlight you will need to rule out a faulty screen before moving on to the logic board but unless you have the equipment and knowhow of microsoldering it might be time for an upgrade as this repair could be worth as much as the phone.

I assume you have completed a full restore to rule out software and tried it in another known good housing to rule out parts. This is what I call the rabbit holes of all rabbit holes. About 4 years ago I had a similar problem I replaced all the RF chips on the bottom of the board plus ran the two jumpers I even replaced the sim tray and ran the second jumper under it. I also got trolled with voltages but I found if restoring with 3uTools about 80% when doing the baseband firmware all the correct voltages showed up. I than replaced the Wi-Fi IC and all the RF components around it just in case it had something  do with it. I than did a board swap which resulted in a short under the PMIC and a short on the 1V8 sdram. After replacing the PMIC and re-balling the ram again I did a full restore only to be confronted with the same problem. I am not sure if the phone had ever been locked to a certain network but after about 40 hours of trying to do the repair I conclude it must be the CPU or baseband.

I think you will find you have a microscopic tear in the flex cable, the one from the screen to the logic board. It usually occurs at the 90 degree bend. You will need to get another replacement screen.