iPhone 6 hangs at 60ma - GSM-Forum

short_toground · 01-18-2017, 19:03

Originally short on vcc_main, traced severe corrosion under pmic so I replaced it.

No more short on vcc_main but when power button pressed bench supply goes to 60ma and hangs never starts booting

pp1v8_always = 1.7v
CPU voltage = .8v
Nand voltage = 3v
Reset_1v8_l = 0v

Diode mode testing reset test point gives me 0 voltage drop. Anyway to determine if it's the CPU or something else pulling it low?

short_toground · 01-18-2017, 19:46

Ok I traced reset line to u1501. Reflowed it and no more short on the line.

However now a new issue, as phone is trying to boot amps jump to 2a (due to current limiting. If I crank to full amps on supply it jumps to that) and then it drops down to 0 until I press power again. And there is no image when powered on.

I've included a video. Anyone know the power on sequence? Looks like whatever gets power a few seconds into the boot sequence is shorted

Pallle · 01-18-2017, 22:09

Hello

Check for short on the backlight circuit.

short_toground · 01-18-2017, 22:17

Quote:

Originally Posted by Pallle

Hello

Check for short on the backlight circuit.

So the short was the baseband pmic. Now phone boots and iTunes recognizes it but no display.

I don't measure a short but backlight diode at cathode only measures 4v (vcc voltage) should be 16v

Pallle · 01-18-2017, 22:35

I think, you need replace U1502 and D1501.

short_toground · 01-18-2017, 23:34

Quote:

Originally Posted by Pallle

I think, you need replace U1502 and D1501.

Anyway to test to make sure? D1501 measures ok. Has a voltage drop one way and none the opposite so it's good.

How can I make sure it's u1502 before replacing?

I need to determine if I have no backlight or no display. Can't see anything when I use a flashlight on the screen

zarbourne · 01-19-2017, 09:24

Quote:

Originally Posted by short_toground

Anyway to test to make sure? D1501 measures ok. Has a voltage drop one way and none the opposite so it's good.

How can I make sure it's u1502 before replacing?

I need to determine if I have no backlight or no display. Can't see anything when I use a flashlight on the screen

This is to know if it's no display, make sure you have the screen connected to board first, then check voltages like in pic

If missing or low, (This means no display), replace U1501, then test... If still nothing replace L1519 (be quick if you are removing one from different board, these are sensitive, if you have new one that would be best).

Let me know if it's backlight gone, not display

short_toground · 01-19-2017, 17:56

Removed u1501 and reballed it. It was corroded. Installed and only 5v1_grape_vddh present measured at c1541

No shorts to ground on the other rails that should be there.

How could I measure l1519 without removing it? Should have done so at the pp_chestnut_lxp pin when had u1501 out.

Do you know if display comes on first then that enables backlight or backlight first enables display?

short_toground · 01-19-2017, 21:36

Ok here's where I'm at:

Replaced u1501 and l1519

Now I have the display and backlight voltages but still no display. Grrr anyone have any ideas? I've checked all filters for display and backlight

UPDATE: the damn connector was dirty lol. All good now

zarbourne · 01-19-2017, 23:05

Quote:

Originally Posted by short_toground

Ok here's where I'm at:

Replaced u1501 and l1519

Now I have the display and backlight voltages but still no display. Grrr anyone have any ideas? I've checked all filters for display and backlight

UPDATE: the damn connector was dirty lol. All good now

Hahaha these things happen sometimes lol

Sent from my iPhone using Tapatalk Pro

short_toground · 01-20-2017, 00:37

Quote:

Originally Posted by zarbourne

Hahaha these things happen sometimes lol

Sent from my iPhone using Tapatalk Pro

Lol acted up again turns out the pad was corroded. Had to run a little jumper.

Now that's set but it's not detecting a simcard. Any idea on that?

zarbourne · 01-20-2017, 01:34

Quote:

Originally Posted by short_toground

Lol acted up again turns out the pad was corroded. Had to run a little jumper.

Now that's set but it's not detecting a simcard. Any idea on that?

Make sure gold pins on simslot are clean. Reball BB PMU. Reball BB CPU.

Test between each step. Let me know how it goes.

short_toground · 01-20-2017, 20:22

Quote:

Originally Posted by zarbourne

Make sure gold pins on simslot are clean. Reball BB PMU. Reball BB CPU.

Test between each step. Let me know how it goes.

Replaced baseband PMU and same issue. No sim detected

If I boot phone with SIM card installed it says "searching" but never changes. If I remove sim it still says "searching"

If I boot without a sim it says "no sim" regardless if I insert one

zarbourne · 01-21-2017, 00:01

Quote:

Originally Posted by short_toground

Replaced baseband PMU and same issue. No sim detected

If I boot phone with SIM card installed it says "searching" but never changes. If I remove sim it still says "searching"

If I boot without a sim it says "no sim" regardless if I insert one

Try to do a network reset, I'll look at schematic soon and see what else

Sent from my iPhone using Tapatalk Pro

short_toground · 01-21-2017, 00:05

I'll have to restore the phone it's password locked.

Btw baseband pmu is PM8019 correct?

01-18-2017, 19:03	#1 (permalink)
short_toground No Life Poster Join Date: Jul 2016 Posts: 536 Member: 2598526 Status: Offline Thanks Meter: 52	iPhone 6 hangs at 60ma Originally short on vcc_main, traced severe corrosion under pmic so I replaced it. No more short on vcc_main but when power button pressed bench supply goes to 60ma and hangs never starts booting pp1v8_always = 1.7v CPU voltage = .8v Nand voltage = 3v Reset_1v8_l = 0v Diode mode testing reset test point gives me 0 voltage drop. Anyway to determine if it's the CPU or something else pulling it low? Last edited by short_toground; 01-18-2017 at 19:29.

01-18-2017, 19:46	#2 (permalink)
short_toground No Life Poster Join Date: Jul 2016 Posts: 536 Member: 2598526 Status: Offline Thanks Meter: 52	iPhone 6 hangs at 60ma Ok I traced reset line to u1501. Reflowed it and no more short on the line. However now a new issue, as phone is trying to boot amps jump to 2a (due to current limiting. If I crank to full amps on supply it jumps to that) and then it drops down to 0 until I press power again. And there is no image when powered on. I've included a video. Anyone know the power on sequence? Looks like whatever gets power a few seconds into the boot sequence is shorted Last edited by short_toground; 01-18-2017 at 19:55.

01-19-2017, 21:36	#9 (permalink)
short_toground No Life Poster Join Date: Jul 2016 Posts: 536 Member: 2598526 Status: Offline Thanks Meter: 52	iPhone 6 hangs at 60ma Ok here's where I'm at: Replaced u1501 and l1519 Now I have the display and backlight voltages but still no display. Grrr anyone have any ideas? I've checked all filters for display and backlight UPDATE: the damn connector was dirty lol. All good now

01-18-2017, 22:09	#3 (permalink)
Pallle Freak Poster Join Date: Jan 2016 Location: Hungary Posts: 362 Member: 2515187 Status: Offline Thanks Meter: 114	Hello Check for short on the backlight circuit.

01-18-2017, 22:35	#5 (permalink)
Pallle Freak Poster Join Date: Jan 2016 Location: Hungary Posts: 362 Member: 2515187 Status: Offline Thanks Meter: 114	I think, you need replace U1502 and D1501.

01-19-2017, 17:56	#8 (permalink)
short_toground No Life Poster Join Date: Jul 2016 Posts: 536 Member: 2598526 Status: Offline Thanks Meter: 52	Removed u1501 and reballed it. It was corroded. Installed and only 5v1_grape_vddh present measured at c1541 No shorts to ground on the other rails that should be there. How could I measure l1519 without removing it? Should have done so at the pp_chestnut_lxp pin when had u1501 out. Do you know if display comes on first then that enables backlight or backlight first enables display?

01-21-2017, 00:05	#15 (permalink)
short_toground No Life Poster Join Date: Jul 2016 Posts: 536 Member: 2598526 Status: Offline Thanks Meter: 52	I'll have to restore the phone it's password locked. Btw baseband pmu is PM8019 correct?