{"id":13051,"date":"2022-03-15T22:02:00","date_gmt":"2022-03-15T14:02:00","guid":{"rendered":"https:\/\/rewa.tech\/macbook-a1466-no-backlight-issue-repair\/"},"modified":"2024-05-10T15:24:48","modified_gmt":"2024-05-10T07:24:48","slug":"macbook-a1466-no-backlight-issue-repair","status":"publish","type":"post","link":"https:\/\/rewa.tech\/fr\/macbook-a1466-no-backlight-issue-repair\/","title":{"rendered":"R\u00e9paration du probl\u00e8me de r\u00e9tro\u00e9clairage du MacBook Air A1466"},"content":{"rendered":"<p>MacBook A1466 no backlight issue repair<\/p>\n<\/p>\n<p><strong>Ph\u00e9nom\u00e8ne de d\u00e9faut :<\/strong> no backlight caused by water damage.<\/p>\n<ul style=\"list-style-type: circle;\">\n<li>We can use the flashlight to check the screen to see whether it is with a display or backlight issue<\/li>\n<\/ul>\n<p><img decoding=\"async\" src=\"https:\/\/rewa.tech\/wp-content\/uploads\/2024\/04\/A1466_no_backlight.png\" alt=\"A1466 No Backlight\" title=\"\"><\/p>\n<ul style=\"list-style-type: circle;\">\n<li>The water-damaged trace can be found on the motherboard, the water damage indicator sticker also turned red.<\/li>\n<\/ul>\n<p><img fetchpriority=\"high\" decoding=\"async\" src=\"https:\/\/rewa.tech\/wp-content\/uploads\/2024\/04\/Water_Damaged_Repair_A1466.png\" alt=\"A1466 Water Damaged\" width=\"1200\" height=\"675\" title=\"\"><\/p>\n<\/p>\n<\/p>\n<p><strong>D\u00e9pannage<\/strong><\/p>\n<p>Clean the motherboard with PCB cleaner thoroughly and check the cosmetics of the motherboard, there is no obvious corrosion, parts missing, or damage.<\/p>\n<\/p>\n<p>Then connect the Macbook with the DC power supply and check the backlight working conditions. After measuring, the voltage on the backlight voltage boost circuit is only 8 volts, which is abnormal.<\/p>\n<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/rewa.tech\/wp-content\/uploads\/2024\/04\/8_Volts_only.png\" width=\"320\" height=\"412\" alt=\"\" title=\"\"><\/p>\n<\/p>\n<p>Let&#8217;s check the basic working conditions of the boost chip first.<\/p>\n<ul style=\"list-style-type: circle;\">\n<li>Chip number: U7701<\/li>\n<li>Location: near the connector J4400 (shown as below picture)<\/li>\n<\/ul>\n<p><img decoding=\"async\" src=\"https:\/\/rewa.tech\/wp-content\/uploads\/2024\/04\/U7701_Bitmap.png\" alt=\"U7701 Bitmap\" width=\"1200\" height=\"617\" title=\"\"><\/p>\n<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/rewa.tech\/wp-content\/uploads\/2024\/04\/U7701_On_the_Motherboard.png\" alt=\"U7701 On the Motherboard\" width=\"1200\" height=\"596\" title=\"\"><\/p>\n<\/p>\n<p>Measure the below 3 working conditions, all values are OK<\/p>\n<ul style=\"list-style-type: square;\">\n<li>PP3V3_S0&nbsp; &gt;&gt;&gt; 3V, <span style=\"color: #339966;\"><strong>OK<\/strong><\/span><\/li>\n<li>PP5V_S0&nbsp; &nbsp; &gt;&gt;&gt; 5V, <strong><span style=\"color: #339966;\">OK<\/span><\/strong><\/li>\n<li>BKL_EN&nbsp; &nbsp; &nbsp; &gt;&gt;&gt; <strong><span style=\"color: #339966;\">Normal<\/span><\/strong><\/li>\n<\/ul>\n<p><strong><span style=\"color: #339966;\"><\/span><\/strong><\/p>\n<p><strong><span style=\"color: #339966;\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/rewa.tech\/wp-content\/uploads\/2024\/04\/U7701_Working_Conditions.png\" alt=\"MacBook A1466 no backlight issue repair\" width=\"1200\" height=\"560\" title=\"\"><\/span><\/strong><\/p>\n<p><strong><span style=\"color: #339966;\"><\/span><\/strong><\/p>\n<p><span style=\"color: #000000;\">For the rest working conditions of U7701, as it&#8217;s with the BGA package, we can only measure them after removing the chip.<\/span><\/p>\n<p><span style=\"color: #000000;\">Remove the U7701 and measure the diode values on the PCB<\/span><\/p>\n<ul style=\"list-style-type: square;\">\n<li><span style=\"color: #000000;\">SW rails: <strong><span style=\"color: #008000;\">OK<\/span><\/strong><\/span><\/li>\n<li>PWM rail: <strong><span style=\"color: #008000;\">OK<\/span><\/strong><\/li>\n<li>FB rail: <span style=\"color: #ff0000;\"><strong>infinite<\/strong><\/span><\/li>\n<\/ul>\n<\/p>\n<p><strong>Processus de r\u00e9paration<\/strong><\/p>\n<p>FB rail infinite, so the inner rail should be broken, check the bitmap we can jump a wire from pin #5 of the U7701 to a backlight test point as below<\/p>\n<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/rewa.tech\/wp-content\/uploads\/2024\/04\/Backlight_Jump_Wire.png\" width=\"498\" height=\"438\" alt=\"\" title=\"\"><\/p>\n<\/p>\n<p>Then solder back the U7701 and test, the issue still unresolved. Backlight power supply shorted to ground. We have to teardown the U7701 chip again and check the pads on the PCB to check if there is any tin bridge, but the tin pads on the PCB are OK.&nbsp;<\/p>\n<p>Measure the FB pin diode value on the chip, it&#8217;s 0. So the U7701 chip also gets damaged.<\/p>\n<\/p>\n<p>We have to replace another new backlight boost IC U7701, then assemble the Macbook to test. After that, the screen backlight is OK and displayed normally<\/p>\n<\/p>\n<p><strong>R\u00e9sum\u00e9<\/strong><\/p>\n<p>A1466&nbsp;820-00165 (2015) no backlight issue get fixed by jumping wire and U7701 IC replacement.<\/p>\n<\/p>\n<p>&gt;&gt; Visit <a href=\"https:\/\/academy.rewa.tech\/\"><strong>Acad\u00e9mie REWA<\/strong><\/a> to learn more repair courses<\/p><\/p>","protected":false},"excerpt":{"rendered":"<p>MacBook A1466 no backlight issue repair Defect Phenomenon: no backlight caused by water damage. We can use the flashlight to check the screen to see whether it is with a display or backlight issue The water-damaged trace can be found on the motherboard, the water damage indicator sticker also turned red. Troubleshooting Clean the motherboard [&hellip;]<\/p>\n","protected":false},"author":10,"featured_media":13052,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"fifu_image_url":"","fifu_image_alt":"","footnotes":""},"categories":[782],"tags":[],"class_list":["post-13051","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-macbook-repair-case"],"_links":{"self":[{"href":"https:\/\/rewa.tech\/fr\/wp-json\/wp\/v2\/posts\/13051","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/rewa.tech\/fr\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/rewa.tech\/fr\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/rewa.tech\/fr\/wp-json\/wp\/v2\/users\/10"}],"replies":[{"embeddable":true,"href":"https:\/\/rewa.tech\/fr\/wp-json\/wp\/v2\/comments?post=13051"}],"version-history":[{"count":0,"href":"https:\/\/rewa.tech\/fr\/wp-json\/wp\/v2\/posts\/13051\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/rewa.tech\/fr\/wp-json\/wp\/v2\/media\/13052"}],"wp:attachment":[{"href":"https:\/\/rewa.tech\/fr\/wp-json\/wp\/v2\/media?parent=13051"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/rewa.tech\/fr\/wp-json\/wp\/v2\/categories?post=13051"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/rewa.tech\/fr\/wp-json\/wp\/v2\/tags?post=13051"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}