{"id":12814,"date":"2021-05-17T20:24:00","date_gmt":"2021-05-17T12:24:00","guid":{"rendered":"https:\/\/rewa.tech\/iphone-7-no-backlight-but-display-can-work\/"},"modified":"2024-05-10T15:29:20","modified_gmt":"2024-05-10T07:29:20","slug":"iphone-7-keine-hintergrundbeleuchtung-aber-display-kann-funktionieren","status":"publish","type":"post","link":"https:\/\/rewa.tech\/de\/iphone-7-no-backlight-but-display-can-work\/","title":{"rendered":"iPhone 7 keine Hintergrundbeleuchtung, aber Display kann funktionieren"},"content":{"rendered":"

iPhone 7 No Backlight But Display Can Work<\/o_p><\/span><\/b><\/p>\n

Malfunction Phenomenon<\/o_p><\/span><\/b><\/p>\n

Press the power button and boot, we can see a faint apple logo on the screen. <\/o_p><\/span><\/p>\n

\"iPhone<\/span><\/o_p><\/span><\/b><\/p>\n

Trouble Shooting<\/o_p><\/span><\/b><\/p>\n

Normally, there are 3 situations can cause this kind of issue.<\/o_p><\/span><\/p>\n

1.<\/span><\/span> Related pins on display connector J4502 was corroded or dirty things on the        <\/span>pin; <\/o_p><\/span><\/p>\n

2.<\/span><\/span> Backlight IC U3701 or combined inductor M2800 or components on the rail was damaged; <\/o_p><\/span><\/p>\n

3.<\/span><\/span> The related rail was disconnected.<\/o_p><\/span><\/p>\n

 <\/o_p><\/span><\/p>\n

We measured the diode values on pin 35, pin 37, pin 39 of display connector J4502. <\/o_p><\/span><\/p>\n

These 3 pins are related with backlight as we checked in schematic. <\/o_p><\/span><\/p>\n

 <\/o_p><\/span><\/p>\n

Pin 35     <\/span>PP_LCM_BL_CAT1_CONN<\/o_p><\/span><\/p>\n

Pin 37     <\/span>PP_LCM_BL_ANODE_CONN<\/o_p><\/span><\/p>\n

Pin 39     <\/span>PP_LCM_BL_CAT2_CONN<\/o_p><\/span><\/p>\n

 <\/o_p><\/span><\/p>\n

\"iPhone<\/span>
<\/o_p><\/span><\/p>\n

 <\/o_p><\/span><\/p>\n

The diode value on pin 35 & pin 39 were normal, but pin 37 was abnormal, it shows “1”, which means diode value was infinite. <\/o_p><\/span><\/p>\n

\"iPhone<\/o_p><\/span><\/p>\n

 <\/o_p><\/span><\/p>\n

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We followed Pin 37 to check the components on the line according to bitmap, and we found the line between FL3901 and J4502 was disconnected. <\/o_p><\/span><\/p>\n

\"\"<\/span>
<\/o_p><\/span><\/p>\n

\"iPhone
<\/o_p><\/span><\/p>\n

 <\/o_p><\/span><\/p>\n

\"iPhone
Pin37 and FL3901 are in different sides of the motherboard, it’s difficult to jump wire on the connector. We checked the motherboard again, there is a test point TP0411 connected with pin37, we jumped wire from TP0411 to FL3901 directly.<\/o_p><\/span><\/p>\n

 <\/o_p><\/span><\/p>\n

After we jumped wire, we tested, backlight was back, problem was resolved.<\/o_p><\/span><\/p>\n

iPhone 7 Repair Online Course<\/span><\/strong><\/a><\/p>\n

\"iPhone\"iPhone\"iPhone<\/o_p><\/span><\/p>\n","protected":false},"excerpt":{"rendered":"

iPhone 7 No Backlight But Display Can Work Malfunction Phenomenon Press the power button and boot, we can see a faint apple logo on the screen. Trouble Shooting Normally, there are 3 situations can cause this kind of issue. 1. Related pins on display connector J4502 was corroded or dirty things on the        pin; 2. […]<\/p>\n","protected":false},"author":10,"featured_media":12815,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"fifu_image_url":"","fifu_image_alt":"","footnotes":""},"categories":[780],"tags":[],"class_list":["post-12814","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-iphone-repair-cases"],"_links":{"self":[{"href":"https:\/\/rewa.tech\/de\/wp-json\/wp\/v2\/posts\/12814","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/rewa.tech\/de\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/rewa.tech\/de\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/rewa.tech\/de\/wp-json\/wp\/v2\/users\/10"}],"replies":[{"embeddable":true,"href":"https:\/\/rewa.tech\/de\/wp-json\/wp\/v2\/comments?post=12814"}],"version-history":[{"count":0,"href":"https:\/\/rewa.tech\/de\/wp-json\/wp\/v2\/posts\/12814\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/rewa.tech\/de\/wp-json\/wp\/v2\/media\/12815"}],"wp:attachment":[{"href":"https:\/\/rewa.tech\/de\/wp-json\/wp\/v2\/media?parent=12814"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/rewa.tech\/de\/wp-json\/wp\/v2\/categories?post=12814"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/rewa.tech\/de\/wp-json\/wp\/v2\/tags?post=12814"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}