DustGate repair: Difference between revisions

DustGate repair
Device	MacBook Pro Retina TBT , MacBook Air Retina TBT , Apple Laptops
Affects part(s)	Display assembly
Needs equipment	soldering iron, replacement glue stripes, replacement LCD Flex cable, 0.02MM solder wire, heating mat
Difficulty	◉◉◉◉ Specialist
Type	Soldering

Revision as of 10:53, 1 April 2024

This article is a stub. You can help Repair Wiki grow by expanding it

Problem description

dust pinches hole through flex data cable between Tcon and LCD. this causes different types of malfunction, mostly with 6 even vertical bars (each corresponds image block of the screen).

typical dustgate

Symptoms

6 pink vertical bars on the screen, might change or flicker with different lid angle
black screen with backlight only (rare, in most cases that would be a cracked screen edge)

The main symptom is the bar pattern. horizontal-lines are caused by damaged LCD / Traces on glass.

Solution

Confirm the issue with a different screen or external monitor, then refer to the (upcoming) Dustgate Repair page.

To repair this issue, you must either repair a broken trace (remove the logoboard and cable fixture to access the edge part of the cable) or replace both cables. If the cable looks good, inspect the LCD under the logoboard for broken or corroded traces between the orange cable and image decoders on the glass.

All cables have the same pinout; however, 15 and 16-inch ones have a longer grounding pin. Cables are very prone to break, so do not bend them near the soldering area and put UV glue on the other side, just like it was done in manufacturing.

After flex replacement, it is normal to have a flickering screen for 10-20 hours of display operation. The suspected reason is a display synchronization problem due to slightly different impedance in a new cable/confused MCU due to a broken trace in the cable. It goes away by itself, also happens after TCON firmware reflashing.

This type of repair requires lots of practice and advanced repair skills to perform.

@@ Line 1: / Line 1: @@
 {{Repair Guide
-|Device=MacBook Pro A2141
+|Device=MacBook Pro Retina TBT, MacBook Air Retina TBT, Apple Laptops
-|Affects parts=Motherboard, Display assembly
+|Affects parts=Display assembly
-|Needs equipment=multimeter, soldering iron, soldering station, BGA rework station
+|Needs equipment=soldering iron, replacement glue stripes, replacement LCD Flex cable, 0.02MM solder wire, heating mat
-|Type=Soldering, Micro-Soldering
+|Type=Soldering
 |Difficulty=4. Specialist
 }}
@@ Line 9: / Line 9: @@
 ==Problem description==
-Possible Diagnoses for Green or Purple Vertical bars on the display
+dust pinches hole through flex data cable between Tcon and LCD. this causes different types of malfunction, mostly with 6 even vertical bars (each corresponds image block of the screen).
-[[File:Placeholder image.jpg|thumb|Example image (Figure 1) -- No image yet. Help expand this page by uploading it!]]
+[[File:Dustgate small pic.png|thumb|typical dustgate]]
 ==Symptoms==
-*Vertical lines on the screen
+*6 pink vertical bars on the screen, might change or flicker with different lid angle
+*black screen with backlight only (rare, in most cases that would be a cracked screen edge)
+The main symptom is the bar pattern. horizontal-lines are caused by damaged LCD / Traces on glass.
 ==Solution==
-The most important diagnostic test to perform, is checking to see if the machine properly displays an image on a KNOWN GOOD display. If the vertical bars are still present on a known good display, the issue is likely related to the GPU or VRAM.
+Confirm the issue with a different screen or external monitor, then refer to the (upcoming) Dustgate Repair page.
+To repair this issue, you must either repair a broken trace (remove the logoboard and cable fixture to access the edge part of the cable) or replace both cables. If the cable looks good, inspect the LCD under the logoboard for broken or corroded traces between the orange cable and image decoders on the glass.
+All cables have the same pinout; however, 15 and 16-inch ones have a longer grounding pin. Cables are very prone to break, so do not bend them near the soldering area and put UV glue on the other side, just like it was done in manufacturing.
+After flex replacement, it is normal to have a flickering screen for 10-20 hours of display operation. The suspected reason is a display synchronization problem due to slightly different impedance in a new cable/confused MCU due to a broken trace in the cable. It goes away by itself, also happens after TCON firmware reflashing.
-Unfortunately, there is no definitive way to determine a VRAM fault from a GPU fault, especially since when this issue is present, the board usually will not boot into an OS. You can try heating the GPU at 100C for 3-5 min to see if the issue will temporarily resolve, if it does, the GPU is the cause of the issue. It is important to note that heating a flip chip at a low temperature for diagnostic purposes is not a solution, and will not "fix" the problem. Higher temperatures should not be used, as they can negatively affect the life of the chipset if it is not the problem. If no change in the problem is seen, the VRAM may be the issue.
+This type of repair requires lots of practice and advanced repair skills to perform.
-If the GPU is the issue, you can reball one from a donor board as long as the proper tools are used. You should be using a BGA station, and you should not exceed 260C during the removal or replacement of the chip. Use 63/37 solder to reball the new chip. DO NOT REBALL THE OLD CHIP. THIS WILL NOT SOLVE THE PROBLEM. If the VRAM is the issue, replace all VRAM chips at the same time.
+[[Category:Apple Laptops]]