iPhone 6s front camera not working

[Sly]

Pin 5 is the PP1V8_FCAM_CONN line. If you have a short on PP1V8_FCAM_CONN as you had mentioned, Pin 5 would be shorted to ground. Your last comment says that pin 5 measured fine.
Could you please explain exactly how did you come to the assumption that pin PP1V8_FCAM_CONN is shorted? What exactly did you measure to assume that PP1V8_FCAM_CONN is shorted?

Good luck!

[eDigitCom]

Yes pin 5 is shorted OK

You are spotting all my typo mistakes

See the PDF I uploaded and it says pin 5 shorted

Thanks

[Sly]

Ok, well If pin 5 is shorted to ground, that means that all of the pp1v8 rail is shorted to ground. The inductor does not seperate the short from one side to the other. For pratical purposes you can condirer it as a wire.
You could remove the filter and then see what side of it the short is located.
Although I'm surprise that the rest of the phone is working because I beleive that line supplies many other functions

[crea2k]

That's exactly what I said earlier regarding the 1.8v line

[crea2k]

Sounds like the short has fried the remainder of the line otherwise the rest like you say would be shorted. So sounds like one of the caps on the remains of the line is short to ground as well as the line being OL from the rest of the 1.8v line. Either that or it's blown out the line and the conn end of the trace is touching ground somewhere. Either way he has a case of 1x short and 1x OL .

[eDigitCom]

I understand what is been said. It is possible I took this reading at another location I have to wait to check whenl I get the phone back

But the phone is not fried If it was I would have been left know I can tell you

I not have the phone in my position at present to check all that we spoke about here

I check all the lines on the connector has shown on the PDF file I uploaded This is all the time I had. Then had to give it back to the customer has needed it for the weekend Waiting on her to get back to me on it

There is no one more interested in the theories we write about here but cannot do anything until I get the phone back


Thanks

[crea2k]

I don't mean the phone is fried I mean the line. On a working phone that line links into the other 1.8v lines. On your phone though it has a short on that line, but the phone still works. If it had a short usually on that line it would stop the phone booting as there would be no 1.8v line on anything. But your phone works. So this would suggest the short has blown out the 1.8v line somewhere between the short and where it splits off from the rest of the 1.8v feeds.
What you should do is first remove the short, then diode mode test the line and you'll probably find it's an open line and needs a jumper back to the rest of the 1.8v lines.

[Sly]

Following what crea2k is saying.

It would make sense that C3100 or C3101 shorted to ground and blown FL3100 at the same time. That would isolate the rest of the PP1v8 line from the short, and make the remainder of the phone work while the front camera would not.

Maybe instead of injecting current in the phone, it would be less intrusive to check FL 3100 for continuity, or see if one side is connected to ground while the other is not.

If this is true, it would make sense that the side of PP1V8_FCAM_CONN of FL3100 would be connected to ground, while the side of PP1v8 would not.

This would mean you only have the option of 2 caps to remove to find the short. Once the short is removed, you would need to replace FL3100 to reestablish continuity from PP1v8 to PP1V8_FCAM_CONN.

[eDigitCom]

Logic sense I have to wait until the phone comes back to me These days people cannot do without there phones and expect them to be fixed in a hour

Great feedback

[Sly]

Urgh... tell me about it haha

[Jessa_the_Professa]

I’m pretty sure I posted this earlier—-this is going to be a cpu data line problem because...that’s how these fail.

your 1v8 is not short, how do we know? Because the phone boots. Don’t believe me? Test—you will have 1v8 on that line.

you listed a bunch of lines telling me that you don’t have a data line problem —-but let’s be more inclusive with the word “data”. A data line for fcam is going to be anything with ones and zeros that is required for the device to understand that an fcam is plugged in, to enable it to turn on, to communicate back and forth actual data, to provide feedback, to modulate its activity under different conditions etc. not just mipi lines.

your fcam is not working because you know that you are missing an Fcam enable line. Hopefully it is a bad or missing filter or problem at the connector, otherwise it is likely within cpu.

[eDigitCom]

This is what I was saying all the time about this problem if the 1v8 volt was shorted then they be much more not working on the phone. This was always my theory above

Regarding a data line you are 100% correct about this.


However were I worked and was taught when someone said there was an open or short on a data line we be looking at the mipl lines (like an 8 bit data bus) The enable lines and clock lines we would call control lines

I was working on equipment where you could connect a special socket to these lines and see the lines on an oscilloscope by triggering on an enable line or a clock slope (positive or negative) so you be getting the information when the chip was enabled.

But these boards were of course not iPhone where I say would be impossible to do something like this However It would be great to be able to this on a phone



I think I be getting the phone back today so will keep people updated

Appreciate all you great advice

Thank You

Jerry

[crea2k]

You can technically do it on an iPhone but you just need a really fast oscilloscope, like £10,000-20,000 fast. That's if you want to capture data anyway because the clock speed is faster than all but the most expensive scopes can handle. If you just want to see if it's turning on and not look at any data etc any old crappy scope should do.

[eDigitCom]

Have the phone back now from the customer will start going deeper into the cause now

[Sly]

Can you clarify if there is a short on that 1v8 line, and if so if the first filter after the pin is blown?

I would help a tone towards knowing where to look next.

A shorted power rail would cause other problems. But, a shorted power rail with with a blown filter would have one side of its rail with a short to ground, and on side fully functional.

[eDigitCom]

UPDATE

Was working on this board all day

Easy enough to find the cause but that Apple Black stuff is a pain to remove


Diode Readings



PP1V8_FCAM_CONN Pin 5 Diode Reading 0.35V


PP2V85_FCAM_AVDD_CONN Pin 7 Diode Reading 0.59V


AP_TO_FCAM_CLK_CONN pin 13 Diode Reading 0.64V

I2C_ISP_TO_FCAM_SCL pin 15 Diode Reading ).502


PP_TO_FCAM_SHUTDOWN_CONN_L pin 17 Diode Reading 0.506

2C_ISP_BI_FCAM_SDA pin 19 Diode Reading 0.509


TOUCH_TO_PROX_RX_EN_FCAM_CONN pin 25 --- OL


I followed the signal TOUCH_TO_PROX_RX_EN_FCAM_CONN taking measurements in Diode mode and Resistance mode. Up to the R3141 it was OL all the way


The resistor R3141 was missing from the board. The other side of the resistor read 0.54v in diode mode This was the PP1V8_TOUCH line


Touch however is now not working has a few components around the resistor was lose and just came away when removing the Apple black stuff

These were FL4251 and C4241 Looking at schematics they are touch related

Found the protection covering difficult to remove I was told in another post that heating it would make it easy to remove. I did not find this helped that much. Maybe I not heat it enough but not take the change in case it may lift caps etc

Also will need it very clean around the pads in the area when the new components have to be replaced All pads good

Any other feedback on how to remove this bloody apple stuff??


Located the components on Digi-Key Found them great, You can go live chat and they will give you a link to the components you need. They give free shipping if you spend $50 or more


https://www.digikey.com/en/resources/homepage

See image attached of location of R3141


Will keep post updated once components replaced


Appreciate all help and feedback

Thank you

Jerry

[Sly]

I use 110 fahrenheit and a sharp x-acto blade. It take some time to get use to it.
Watch out for cutting tracing on the board if your using a blade.

It is easy to pry off components if your tool is too thick and your trying to remove that black stuff between components. Keep trying and learn from your mistakes. We all do mistakes. They will make you better at your job if you learn from them. Don't let a mistake go to waste.

At 110 you dont really need to worry too much about over heating the board, although you still want to be careful. Once the stuff is warm enough it comes off pretty easily.

Note: They use a different type of black stuff on certain IC which is harder to remove.

[eDigitCom]

Sly thank you this worked great. With the gun you know exactly what temp you can set. Worked like a dream


Now I wondering how to deal with these new miniature caps , resistors and filters in how to get them on to the logic board. To the naked eye you not see them hardly,and then to transfer the new once from the plastic bag they come in, to under the microscope and the final step to get them in place and then to solder them to the board.


Thanks again

[Jessa_the_Professa]

Re: Apple black silicone---use something very very very fine----like a sewing needle. I use a particular pair of dumont tweezers that are extremely fine pointed, but they break all the time and are expensive. I constantly file tweezers to be fine enough for this work. With 200C hot air and a very very very very fine tool, removing the silicone is no problem.

My advice for reinstalling--tin the pads with the mini hot tweezers, and then the components will go back on nicely. If this is a customer board that you intend to fix, then first practice on another board---components around a 5s or 5c battery connector is a similar project but with more space to learn how to manipulate little dudes.

Moving little guys around is all about surface prep. Fresh puffy pillows with not too much solder = easy job. Anything else = all day struggle.

Just put back on the resistor and the missing filter to see if it works before trying for the cap.