Skip to main content

Everything you need to repair your iPhone yourself! From the newest iPhone 15 lineup, all the way back to the original iPhone 2G released in 2007, iFixit has free repair guides and disassembly information for every single iPhone, as well as the best replacement parts, tools, and tips in the galaxy.

36384 Questions View all

Port Board Logics or Tristar Chip?

I have been repairing phones for a while now as well as watching a lot of repair videos and I have a question about troubleshooting charging issues.

I see a lot of folks start with a USB multimeter, see the phone pulling no amps and try a good and charged battery. Phone turns on, still not pulling any amps, instantly blame the tristar chip on the main board.

I have often tried to hang a good charge port off the side of the phone and it pulls amps with a new charge port (not the port itself has gone bad physically, but the logics or SMDs on the port cable/board).

If the tristar is bad, will it just slowly kill a new charge port??

Answer this question I have this problem too

Is this a good question?

Score 0
Add a comment

1 Answer

Most Helpful Answer

Haven’t heard of a bad tristar killing a charging port.

Usually if unlucky it’s the charging port that dies with the tristar at the same time. Usually it’s just the tristar chip that fails from a combination of aftermarket cables and wall chargers.

Was this answer helpful?

Score 3

2 Comments:

After repairing a few thousand iPhones, I have found very few phones with charging problems that were not fixable with a port change. I realize the main culprit for dead tristars is flat out cheap cables and chargers, but it seems that is also the main reason for port failures. My theory is that port logics act like a fuse for the tristar in many but not all cases. I do not do board level work, but I get a lot of no-charge status phones. Number one reason seems to be a bad battery the phone refuses to charge likely out of safety concerns. Number two is the port logics, and very rarely I find its the board…as a minor of fact I can not remember the last time I even had a case where the phone powered up with charged battery but would not charge the battery after a port change. Maybe this is not as common with the 7-X

by

In my experience I find out that the iPhones with bad tristar have a dead flat battery that works when plugged into an external battery charging board to jump start the battery to make it work again.

The most common symptom you probably have heard of is that everything charging related to the phone works except it can't charge flat batteries.

The newer phones (7 and higher) have a more robust Tristar chip / charging circuit so they fail less often than the previous iPhones.

by

Add a comment

Add your answer

Nate Thibault will be eternally grateful.
View Statistics:

Past 24 Hours: 0

Past 7 Days: 1

Past 30 Days: 3

All Time: 234