6s+ short on GPU and CPU Help - GSM-Forum

short_toground · 01-05-2017, 03:19

Have a water damaged iPhone 6s+ that has a short on both pp_gpu and pp_cpu lines.

I've applied power directly to those lines individually and in both instances the same area gets warm which seems like the CPU itself.

How could I in fact determine if it's the CPU and not the PMU chip?

cosmin96 · 01-11-2017, 21:03

I have the same problem. Do you find the issue?

short_toground · 01-11-2017, 21:34

Quote:

Originally Posted by cosmin96

I have the same problem. Do you find the issue?

Yes it's a fault short. Both those lines have very low ohm readings. Use diode mode to verify they are not 0 ohms, a low reading is normal. 0 reading isn't.

I compared to a known good board to understand it.

cosmin96 · 01-11-2017, 22:07

PP_CPU show 44 ohms and PP_GPU show 10.2ohms. Both get a beep in diode mode.
Is It normal?

short_toground · 01-12-2017, 00:54

Quote:

Originally Posted by cosmin96

PP_CPU show 44 ohms and PP_GPU show 10.2ohms. Both get a beep in diode mode.
Is It normal?

Seems pretty normal. On my good board I measure 10ohms on pp_gpu and 22ohms on pp_cpu

mosaique_boy · 01-12-2017, 02:43

I like this conversation

ro_24 · 01-12-2017, 03:03

nice share sir..now i have a idea..thanks....

short_toground · 01-13-2017, 15:32

Keep in mind that if you are working with complex chips (like CPU/GPU chips) you will get a low reading, the bigger the chip, the lower the reading will be.

That's the take away here

nerowebx · 09-22-2017, 07:09

Any news about this problem ?

mosaique_boy · 09-24-2017, 14:02

the only way to know if you have a short is to compare with a good board with diode mode

Handy Reparatur Bensheim

01-05-2017, 03:19	#1 (permalink)
short_toground No Life Poster Join Date: Jul 2016 Posts: 536 Member: 2598526 Status: Offline Thanks Meter: 52	6s+ short on GPU and CPU Help Have a water damaged iPhone 6s+ that has a short on both pp_gpu and pp_cpu lines. I've applied power directly to those lines individually and in both instances the same area gets warm which seems like the CPU itself. How could I in fact determine if it's the CPU and not the PMU chip?

01-11-2017, 21:03	#2 (permalink)
cosmin96 Junior Member Join Date: Jan 2013 Posts: 13 Member: 1865746 Status: Offline Thanks Meter: 0	I have the same problem. Do you find the issue?

01-11-2017, 22:07	#4 (permalink)
cosmin96 Junior Member Join Date: Jan 2013 Posts: 13 Member: 1865746 Status: Offline Thanks Meter: 0	PP_CPU show 44 ohms and PP_GPU show 10.2ohms. Both get a beep in diode mode. Is It normal?

01-12-2017, 02:43	#6 (permalink)
mosaique_boy Freak Poster Join Date: Sep 2009 Location: Germany Posts: 214 Member: 1124915 Status: Offline Thanks Meter: 13	I like this conversation

01-12-2017, 03:03	#7 (permalink)
ro_24 Junior Member Join Date: Jan 2017 Posts: 5 Member: 2671246 Status: Offline Thanks Meter: 1	nice share sir..now i have a idea..thanks....

01-13-2017, 15:32	#8 (permalink)
short_toground No Life Poster Join Date: Jul 2016 Posts: 536 Member: 2598526 Status: Offline Thanks Meter: 52	Keep in mind that if you are working with complex chips (like CPU/GPU chips) you will get a low reading, the bigger the chip, the lower the reading will be. That's the take away here

09-22-2017, 07:09	#9 (permalink)
nerowebx Freak Poster Join Date: Oct 2004 Age: 47 Posts: 129 Member: 85529 Status: Offline Thanks Meter: 5	Any news about this problem ?

09-24-2017, 14:02	#10 (permalink)
mosaique_boy Freak Poster Join Date: Sep 2009 Location: Germany Posts: 214 Member: 1124915 Status: Offline Thanks Meter: 13	the only way to know if you have a short is to compare with a good board with diode mode Handy Reparatur Bensheim