An issue: an original iPhone display touch screen does not respond
Sometimes repair masters and service centers face a problem that is, when installing the original iPhone 7, 7+, 8, 8+, 11 or XR display, the touch screen does not work: it stops properly operating right after having been installed, or after a few days. Of course, you can consider the display as defective and send it back for an exchange - but the issue is not so simple. Let's figure it out.
To cut a long story short:
I am sure that most of our customers already know what does C11 C3F DTP mean, but we still receive questions on this topic, so we provide the following information in order to avoid misunderstandings.
In the catalog, we indicate the differences between 3D touchscreens as follows:
LCD Apple iPhone 11 (USED C11) - may not work on all versions of phone boards.
LCD Apple iPhone 11 (USED C3F) - universal, work on any board.
This is in short. Let's consider in detail below.
Different manufacturers - different calibration and compatibility settings
Displays, for example for the iPhone 8 and 8+, are made by three companies; LG, Toshiba and Sharp. While the displays themselves meet Apple's stringent requirements, compatibility between iPhone boards varies greatly. If you look at the 3D touch panel (on the back of the display, under the cable), you will see a long alphanumeric code. The first three letters identify the manufacturer of the display and the 3D touch panel, and the remaining digits are the serial number unique to each display. This information is also contained in a QR code on the back of the Display and is stored on the Apple GSX server along with the device's IMEI and serial number. This is the way Apple can figure out whether the iPhone's LCD has ever been replaced.
For example, Toshiba manufacturer puts its own 3D touchscreen in the production of the display. Same for LG and Sharp. When the iPhone is assembled at a factory such as Foxconn and the first Display is installed, Apple uses a special calibration machine to calibrate the iPhone to work with the Display. Also, a similar calibrator is used if you change the iPhone screen in the official Apple service. At this point, it doesn't matter if the iPhone gets an LG, Toshiba, or Sharp display, as the calibration machine will make sure it's set up correctly. The problem arises when the screen is replaced by a third party who will definitely not have access to such a machine, and this is 99% of all repairs made in Russia.
Yes, we agree that craftsmen from China have already learned how to make programming devices that will reflash or calibrate microcircuits on a 3D cable, you can replace the microcircuit from the original display (if it cannot be restored), or replace the cable - but this is a topic for another article.
The probability of facing a touchscreen failure and what to do about it
If the iPhone has been calibrated for a Toshiba or Sharp display, and you set Toshiba to Sharp or vice versa, there is about a 5-10% chance that the touchscreen will not operate. If the iPhone was originally calibrated for an LG display and you are using a Toshiba or Sharp display, then there is a 50% chance of touchscreen issues because LG's sensitivity range is very different between the two manufacturers.
If you don't have the coveted calibrator that informs the iPhone that you've installed a different manufacturer's display, then your touchscreen will most likely fail if you don't install an LG display. So, if you install a display and the touchscreen doesn't work, and then install another display and it works, you're probably discarding the display - which is a big mistake. Just try this display on another board - it should operate normally.
Codes according to manufacturers
LG - DTP, C3F.
Sharp - DHK, C01.
Toshiba - C11, F7C.
Let me remind you that this only applies to OEM (new original ones from the brand holder’s factory), USED (removed from used phones), Teardown (removed from new phones), Refurbished (restored originals, with a usually replaced glass and frame) displays.
I hope that the article was useful to you!