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这款4.7英寸iPhone于2014年9月19日发布,是iPhone 6 Plus的缩小版。

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Problem getting to PP1V2_SDRAM components

Hi, working on iPhone 6 that won't boot. When first opened looked really clean, but then started to notice various problems. No Tristar or Q1403 (both replaced) and some caps pulled. Most odd was that one side of the metal housing had been cut away, near the PMIC. When I first plugged this in it was dead with no current draw on my ammeter. After replacing Tristar & Q1403 and some caps it began to draw current, at around 500 mA but started getting really hot at the top end of the back of the board. Removed it from the charger and had a look around. Checked all of the bigger caps and eventually found a short on PP1V2_SDRAM. The issue is that virtually none of the components on this line in the area can be accessed apart from the 2 big caps in the backlight area; they seem to be recessed under the metal casing around the sides (C0211, C0433,C0434, C1278 etc). I think that maybe whoever worked on this previously also figured this out but cut away the wrong side of the casing (!) and just gave up. I obviously don't want to start cutting away parts of the casing just to check caps; so the question is - is there any other way to troubleshoot this?? (And also, would a short on this line stop the phone from booting?)

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Are you measuring a dead short or low resistance?

Yeah, that line is a little inconvenient. Still, there are a few components you could remove, such as C1295, C1288, C1216, C1214 on the top side and C0423, C0429 and possibly C0422 on the back side. Of course, if your confident, you could also remove the PMIC to see if the short is in there or downstream. Finally, you can also desolder the ribbing (the metal frame for the cloth shield) completely to get access to the other components.

Of course, the real risk is that the short is in the SDRAM. Yuck!

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George Wright 将永远感激不已
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