iPhone 7 (1660) No Service

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iPhone 7

2016年9月16日に発売。モデル番号は1660, 1778で GSM かCDMA があり。/ 32、128、 256 GB / 色はローズゴールド、ゴールド、シルバー、ブラック、ジェットブラック

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Preston Elrod @cheapphonesusa

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CheapPhonesUSA

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投稿日: 2020年4月29日

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iPhone 7 (1660) No Service

Hey! I have an iPhone 7 with no service issue. I am a micro-soldering technician but I am new to it. The iPhone does not show IMEI and putting a sim card into the sim port does not change or affect the status. I am wondering if I should start at the baseband or the Qualcomm chip that I hear normally fails. Thanks for your answers and I hope you have a great day!

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Based on my readings, the capacitors around the chip are shorted. I assume that it’s the chip and not the caps themselves (I’ve tested 6 of them).

————————-Edit————————-

Removed the chip successfully, shorts and cleared and upon further inspection of the chip there is a bulge on it which I call: “The fry mark”.

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Can anyone help?

Preston Elrod さんによる2020年5月3日

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Chris Stables @imicrosoldering

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投稿日: 2020年4月29日

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I would start at the Baseband PMU if it is a QUALCOMM unless it has an audio IC repair done which would point to the Baseband CPU. If it hasn’t had the audio repair I would suspect the baseband PMU has suffered an electrical fault thus sending the wrong voltage to the baseband CPU making the phone unfixable as the baseband CPU is married to the phone.

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No audio repair has been done to this board, I was expecting the BBPMU as well. Would replacing this chip resolve this problem or is this a death sentence for all iPhone 7’s?

Preston Elrod さんによる2020年4月29日

@cheapphonesusa It is only a death sentence for the Qualcomm ones as the BBPMU is located closer to the flex line unlike the Intel.

You will need to find what line is shorted. You should be able to multimeter around the BBPMU to find the line. You can than remove baseband PMU and check if the short has gone. If you cannot find anything there you would need to diode all the baseband CPU lines. If nothing turns up replace the BBPMU, you might get lucky.

Chris Stables さんによる2020年4月29日

@imicrosoldering Ok, currently I do not have a multimeter with diode mode, my current plan is to check the caps around the pmu. Hope they are shorted and then remove the pmu and check if short clears. If not replace caps, if so replace pmu

Preston Elrod さんによる2020年4月30日

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No audio repair has been done to this board, I was expecting the BBPMU as well. Would replacing this chip resolve this problem or is this a death sentence for all iPhone 7’s? — Preston Elrod
@cheapphonesusa It is only a death sentence for the Qualcomm ones as the BBPMU is located closer to the flex line unlike the Intel.

You will need to find what line is shorted. You should be able to multimeter around the BBPMU to find the line. You can than remove baseband PMU and check if the short has gone. If you cannot find anything there you would need to diode all the baseband CPU lines. If nothing turns up replace the BBPMU, you might get lucky. — Chris Stables
@imicrosoldering Ok, currently I do not have a multimeter with diode mode, my current plan is to check the caps around the pmu. Hope they are shorted and then remove the pmu and check if short clears. If not replace caps, if so replace pmu — Preston Elrod

Allan Barr @barriphone 評価: 7.2千 Barr iPhone Repair 4 2 2 · Answer 1 · 2020-04-29T20:40:19-07:00

Allan Barr @barriphone

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Barr iPhone Repair

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投稿日: 2020年4月29日

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Has this phone been hooked up to a carrier before? It could have been a display phone and it cannot be hooked up to service.

It should looks like it was a display, it doesn't have a IMEI number. So I would bet with a 99.99 percent possiblity that it was a display. They do that so people can't steal them and hook them up.

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I would doubt it but that could be a possibility, I bought this phone in wholesale from BuyBack Boss.

Preston Elrod さんによる2020年4月29日

The phone is stuck on No Service, all the evidence points to the fault in the motherboard.

Preston Elrod さんによる2020年4月30日

this is not how demo units work, the 7's are littered with problems

Ray Shipler さんによる2024年8月15日

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