MacBook Pro A2289 No camera detected repair and MacBook Pro A2289 No post, boot, or image with initial fan spin, drawing 0.2A at 20V repair: Difference between pages

MacBook Pro A2289 No post, boot, or image with initial fan spin, drawing 0.2A at 20V repair
Device	MacBook Pro A2289
Affects part(s)	Motherboard, Camera, Display assembly
Needs equipment	multimeter, soldering iron, soldering station
Difficulty	◉◉◉◌ Hard
Type	Soldering

Latest revision as of 15:28, 29 October 2023

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Problem description

820-01987 MacBook fan spinning initially but not posting, booting, or showing an image.

Example image (Figure 1) -- No image yet. Help expand this page by uploading it!

Symptoms

Drawing 0.2A at 20V as measured with a USB-C meter
No picture
Initial fan spin

Solution

Diagnostic Steps

Dead U7710/U8110

This is a signature fault on the 820-01598 and 820-01987 logic boards.
- The VCCIO (U8110) and EDRAM (U7710) buck converter controller ICs fail in unison, resulting in a no POST/boot condition.
- You will often observe that the fan spins briefly and the amperage (as measured on the USB C amp meter) will settle around 200ma (0.2A)
Measure PP0v95_S0_CPUVCCIO_REG_R on L8102.
- If voltage is present, this is not your issue.
- Measure the PVCCIO_EN signal at R8165, It should be present at 3.3v.
- Measure the PPVCCEDRAMS0_EN_FILT_BUF signal at R7766 - It should be present at 3.3v
- If any of those is missing, proceed to the repair steps below.

Repair Steps

If both enable signals are present, and PP0v95_S0_CPUVCCIO_REG_R is missing, replace BOTH U7710 and U8110.
Typically, when this fault occurs, you will have either no backlight or no camera function after the repair.
- It is unknown why this happens, however it probably is related to either the backlight driver serial communication or camera serial communication somehow overloading parts of the CPU, causing it to draw more power than the chips are rated for causing this issue.
- If the device has no backlight after the repair:- Replace U8400
If the device has no camera function after the repair:- Replace the display assembly

@@ Line 8: / Line 8: @@
 {{stub}}
 ==Problem description==
-Addressing issues with MacBook Pro ''820-01987'' not detecting the camera.
+''820-01987'' MacBook fan spinning initially but not posting, booting, or showing an image.
 [[File:Placeholder image.jpg|thumb|Example image (Figure 1) -- No image yet. Help expand this page by uploading it!]]
 ==Symptoms==
-* Camera not detected
+*Drawing 0.2A at 20V as measured with a USB-C meter
-* Possible burned or exploded L8504 filter on TCON board
+*No picture
+*Initial fan spin
 ==Solution==
 ===Diagnostic Steps===
-==== Check L8504 Continuity ====
+==== Dead U7710/U8110 ====
-* Use a multimeter in continuity mode to check L8504 (Figure 1).
+* This is a signature fault on the 820-01598 and 820-01987 logic boards.
-* Normal reading should be close to 0.01.
+** The VCCIO (U8110) and EDRAM (U7710) buck converter controller ICs fail in unison, resulting in a no POST/boot condition.
-* If L8504 is blown or burned, proceed to the "L8504 blown or visibly burned repair steps" below.
+** You will often observe that the fan spins briefly and the amperage (as measured on the USB C amp meter) will settle around 200ma (0.2A)
+* Measure PP0v95_S0_CPUVCCIO_REG_R on L8102.
-==== Test with Known Good Display ====
+** If voltage is present, this is not your issue.
+** Measure the PVCCIO_EN signal at R8165, It should be present at 3.3v.
-* Verify camera function using a KNOWN GOOD display assembly.
+** Measure the PPVCCEDRAMS0_EN_FILT_BUF signal at R7766 - It should be present at 3.3v
-* If the camera works with a different display, the original display might be faulty.
+** If any of those is missing, proceed to the repair steps below.
-* Make sure to check L8504 before diagnosing the display issue.
 ===Repair Steps===
-==== Camera Works with Known Good Display ====
+* If both enable signals are present, and PP0v95_S0_CPUVCCIO_REG_R is missing, replace '''BOTH U7710 and U8110.'''
-If camera works with a known good test display, replace the display assembly.
+* Typically, when this fault occurs, you will have either no backlight or no camera function after the repair.
+** It is unknown why this happens, however it probably is related to either the backlight driver serial communication or camera serial communication somehow overloading parts of the CPU, causing it to draw more power than the chips are rated for causing this issue.
-==== L8504 Blown or Visibly Burned ====
+** '''If the device has no backlight after the repair:'''- Replace U8400
+* '''If the device has no camera function after the repair:'''- Replace the display assembly
-* Understand that L8504 failure indicates a catastrophic short within the TCON board of the display or a melted/corroded display cable/connector.
-* Repair L8504 only after addressing the display issue, as L8504 might fail again if the display issue persists.
-* When replacing L8504, address corresponding pad and trace damage.
-* Use 36 or 37 AWG enamel coated copper wire for jumper wires due to webcam and ambient light sensor power requirements.
-* Connect jumper wire from the input side of the filter (PP5v_G3S) to R5610 (Figure 2) or a suitable point.
-* Apply conformal coating to jumper wire.
-* Use a 120 Ohm ferrite filter rated for 1.5 amps (402 package size).
-* After replacing L8504 and addressing trace issues, replace the display assembly or repair it by replacing damaged cables/connectors.
-==== No Camera Function, L8504 Normal ====
-* Attempt to restore T2/BridgeOs firmware via Apple Configurator 2 by entering DFU mode.
-* Ensure your Mac is on the latest macOS version.
-* Follow Apple's support article on reviving or restoring T2/BridgeOs firmware.
-* If no camera function after firmware revive, and other causes are ruled out, U8504 might be faulty, or there could be trace/resistor issues between the camera connector/U8504 or between U8504 and the T2 chip.
-* A hardware issue with the T2 chip might also cause camera detection problems.