iPhone and iPad Dim Screen
The Important Points
- If your iPhone or iPad has a dull screen that doesn’t “light up”, it’s probably a backlight issue. We can fix this! Contact us online for more details or visit our store.
- The backlight is the rearmost layer in the LCD and makes it light up. If the backlight or related circuit fails, the screen will no longer glow.
- Poor-quality copy screens can overload the backlight circuit and cause it to fail after a while. This turns a cheap screen replacement into an expensive repair. We always recommend good-quality refurbished screens where possible.
- Backlights can also fail under “regular” use due to water/liquid damage.
- Backlight circuit repair can be risky in less experienced hands. In addition, if a business cuts its prices too low, it often can’t afford the time- and risk- to do the job properly.
- Many businesses focus on simpler repairs that can be done using by-numbers “parts swapping”. This is fine as far as it goes, but doesn’t work for more complicated repairs.
- Board-level repairs are far more complex and risky, and require far more experience and training. That’s why they cost more and can’t be compared to “parts swaps”.
- We’re not always the very cheapest, but we have years more experience than most of the competition and won’t cut corners with your valuable iPhone or iPad
Introduction
If your Apple iPhone or Apple iPad is having problems with a dim screen, it’s almost certain that the fault is related to the backlight.
Modern LCD screens have three layers. The LCD panel itself sits in the middle, but on its own this is just an unlit black-and-white display (think of a higher resolution version of the old-style LCDs used in digital watches or early Nintendo GameBoys). At the front, a filter layer adds colour, but it’s the backlight shining from behind that makes your phone’s screen light up. If this backlight fails, your screen will be very dark and only be visible under strong light. However, very often this problem is caused not by the failure of the backlight itself, but by the related “backlight circuit” that powers and controls it. It’s damage to the backlight circuit- rather than the backlight itself- we’ll be concentrating on here.
Fortunately, it’s possible to have these “dim screen” backlight problems repaired. If you don’t want to read this entire article, the short version is- bring it to us. We can often fix the problems that others can’t… and we know how to avoid the mistakes that can lead to them happening in the first place.
Where The Damage Happens- The Backlight Circuit
The backlight itself is powered by the “backlight circuit”. To simplify things somewhat, the main components of this circuit are a coil, backlight IC, diode, filter and some capacitors, iPhone, Smartphone and iPad Dim Screen.
Some newer Apple devices- from the 6S upwards- have the circuit in two parts, one for each side of the screen. If the part associated with one half gets damaged, half the screen will go dull.
(Very occasionally, a dull display can be caused by the FPC connector to the LCD getting squashed, rather than damage to the backlight circuit. However, this is very rare.)
Fixing the Backlight Circuit- Not Always Simple, Often Risky
There’s more than one potential cause of backlight circuit failure, and they’re not all equally simple to fix- some repairs can consist of a simple filter replacement, and others can require replacing the whole circuit or adding jumper wires to bypass damaged tracks. This is easier on some devices than others.
Sometimes extreme current or overvoltage can cause filters to have literally exploded and damaged the solder pad. In addition to the filter replacement, our technician must solder jumper wires to other points in such cases. Damage can also be caused by heat during repair. In order to reduce this risk, some stores and technicians used a CNC to cut the IC away from the board. (iPhone Smartphone and iPad Dim Screen) While this was never particularly common, it’s still done. Problems (and hence damage) can be caused if the CNC programs- designed around a specific circuit layout- contain bugs or errors. However, in principle, there shouldn’t be a risk with this method.