How to test Chestnut output voltages iPhone 5c

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iPhone 5c 维修

苹果 iPhone 5c 于2013年9月10日发布。该设备的维修与以前的型号相似，需要螺丝刀和撬机工具。提供GSM或CDMA / 8,16,32 GB /白色，粉红色，黄色，蓝色和绿色。

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pts8091 @pts8091

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发帖于: 2019年9月26日

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How to test Chestnut output voltages iPhone 5c

Im fixing an iPhone 5c, with display issues after a drop. The measurements i got in diode mode are:

Vcc main 0.153

Batt vcc 0.410

I tested all of the pins on the J5 connector that I thought could have something to do with image. There were two OL results:

PN5V7_LCM_AVDDN_CONN

LCD_PIFA

I know that the first one, PN5V7 LCM, comes from Chestnut. Is it likely a shorted cap on this line?

I tried testing output voltages from Chestnut, but I cannot figure if i am doing it correctly. I hooked up my DCPS and measured that 4.5v was getting to Chestnut at C47. But when i went to measure an output voltage at C329 i get no volts. How do i measure output volts at Chestnut or Tristar or even Pmic?

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Minho @refectio

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PN5V7_LCM_AVDDN_CONN typically gives an OL reading or ~1.500V. Obviously an OL reading is not indicative of a short, on the contrary, it represents an open circuit.

Your VCC_MAIN reading seems a bit low to me, indicating some short somewhere downstream causing issues. Check the other PP signals on Chestnut (PP5V7 LCM and SAGE) as well as the BOOST line. Check them in diode mode first to see if any are shorted.

The 5C is a horrible device to work on :-(.

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When i have power through the dcps at say 4.2v i get that on VCC main, but any outputs from Chestnut such as BOOST, measured at C329 are 0.000v?

由 pts8091 完成的 2019年9月26日

Looks like you may have a defective/damaged Chestnut. Measure the rails in diode mode to see if they are shorted, If they are, check the circuit from the IC to the connector to see if there is any obvious damage to the components. At that point, you can either remove a filter to see if the short stops there or remove the IC.

由 Minho 完成的 2019年9月26日

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When i have power through the dcps at say 4.2v i get that on VCC main, but any outputs from Chestnut such as BOOST, measured at C329 are 0.000v? — pts8091
Looks like you may have a defective/damaged Chestnut. Measure the rails in diode mode to see if they are shorted, If they are, check the circuit from the IC to the connector to see if there is any obvious damage to the components. At that point, you can either remove a filter to see if the short stops there or remove the IC. — Minho

iPhone 5c 维修

How to test Chestnut output voltages iPhone 5c

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