Hypothetical question - iPhone PMU

Tony Tone

Is it possible to have all the power rails working coming out of the PMU but one? So like if you had just one rail not working you would have to change the PMU?


New member
Yes I had that already. A 4s had water damage and the PMU had internal short. I replaced it with a new one from China and it would not turn on as a power rail was missing. I thought I had a bad install but reflowing and reballing did not solve. I harvested a PMU and this time it worked and all the power rails were present.
Also, you have to make sure all the enable lines are present and that the components needed present also. Such as when testing display voltages, the display must be connected.

Tony Tone

Louis needs to add a buy a beer button.

Thank you. I always wonder about stuff and have no one else to ask for clarification. I thank you immensely.
Yes, of course forgot about checking enables! & thnx for the tip on the screen being connected. That used to throw me until I found out, jeeezzuss.
Lots of things to keep in mind and things I keep pondering. Like Louis says you gotta think, use your brain. So thanks for the reinforcement.

This phone is actually not water damaged. A tech knocked off a cap and I guess all hell broke loose. Backlight fuse blown 2 holes (wire off near the diode fixed), and another fuse and 3V mesa. I'll figure it out or save it for another day. But I was just wondering about there being that possibility.

(already have the pmu's, I'll try it next week maybe).