iPad mini 1 - OL on PPVBUS_CONN

[Jenzo]

Hi,

Working on an iPad mini 1 for data recovery. At first I thought it was back docking flex, so I replaced it, but still no charge.

Device is taking 0 amps. When checking my soldering job I measured OL on all PPVBUS_CONN pads. Traced the line, 5V gets to the tristar, so no clue how to continue from here. Should I just assume tristar is bad?

[mon2]

Re: iPad mini 1 - OL on PPVBUS_CONN

It is very possible that the tristar IC is defective and needs to be replaced but do you have a lightning breakout test board ? Or perhaps a Tristar tester?

Ben's Tristar from Germany is good but has a design flaw which he was being stubborn to listen to our advice. He is unable to charge the module using Type C PD power adapter connector. We shared the fix but he is in denial and does not believe there is a flaw. Our free consultation services are closed for his case.

With the lightning breakout board, you can perform diode mode testing to determine if the tristar is defective. Plan B is to just replace it but be aware that it is a tiny bugger and will take extreme care and proper tools / skills to replace it. There are some good videos from Louis and Alex (Northridge) - both helped us to learn the process. Louis with his 'make it dance' is priceless. Lots of flux and hot air in circles till the IC 'dances' -> remove it -> apply standard leaded low temp solder -> flatten with soldering braid -> flux and apply a fresh tristar IC.

Plan C is to seek out a local cell phone tech shop that probably does this repair daily.

[Jenzo]

Re: iPad mini 1 - OL on PPVBUS_CONN

Hey Mon!

I do have a tristar tester (this one: http://tristartester.com/en/), it indicated docking flex, that's why I replaced it in the first place. But it keeps failing the test 9 out of 10 times when testing again with the tristar tester. I triple checked my work on the docking connector, so very sure that's not the actual issue.

Don't have a breakout board, sorry.

I have experience with iphone 7/8 tristars, did about 15 of those so far so I should be fine on replacing this one. I just like to avoid unnecessary risk. And I did learn mainly from those 2 people indeed haha, and don't forget Jessa!

Guess I'll just replace it then, thank you for the advice!

[Jenzo]

Re: iPad mini 1 - OL on PPVBUS_CONN

Replaced the tristar, but no luck. Line keeps measuring as OL.

My next assumption was that it's the zener diode, dz5701, but took it off and it measures correct.

Mosfet Q5700 has 4.8v on source and drain, 0v on gate.

Mosfet Q5701 is not letting power trough, I have 4.8v on source and 4.6v on gate.

I'm lost :')

[mon2]

Re: iPad mini 1 - OL on PPVBUS_CONN

I think we are going through a similar h*ll with these ipads. Parts are so small and personally not using a microscope. Ours is the A1566 ipad AIR 2.

Which model is yours for the logic board # ?

So far, have replaced the dockflex cable -> still the unit consumes ~15mA. Then replaced the tristar, a few times with the 610A3B (backwards compatible with the original A2).

No difference in the current consumption and the battery is not charging. The replacement battery just kept draining and now down to 1%. Ran out of time on Friday and may go to the office tomorrow to catch up but observed that the PMIC IC is heating up to ~45C upon FIRST power on of the button press. That is, if we power cycle, the consumption is ~3.5A !!!! (immediately for a few seconds) then down to 15mA. Found a video on youtube and also a chinese paid database of ipad repair cases and the fix is the same, replace the PMIC. We brought in the PMIC IC but was too tired on Friday. Perhaps review your case as well for the same. FYI - have another identical model with 100% same fault. The client just abandoned the unit and did not even pay us for the review. We will now fix it and just flip it.

If you share the logic board #, will check if we have the schematic for ideas but getting too old for these tiny buggers to handle by hand. Our next SMT machine can support under 01005 SMD parts (world's smallest) but totally different game if a machine is placing the part.

[Jenzo]

Re: iPad mini 1 - OL on PPVBUS_CONN

The board number is 820-3400-A if I'm not mistaking.

The iPad I'm working on has no current draw at all, when looking at some other cases I noticed that often it's PMIC indeed, but it's not heating up under the thermal cam at all. As far as I can tell, power isn't even reaching PMIC (U8100 on the schematic).

It bothers me that the fault seems to be straight forwards, only so many things can cause an open line :') Yet here I am, failing haha

And damn that machine sounds nice!

[mon2]

Re: iPad mini 1 - OL on PPVBUS_CONN

If you have 0.00A of current draw then the issue is with the dockflex cable.

It is possible that the dockflex cable is not properly soldered onto the PCB. If indeed it is, then you should be able to measure 5V from your USB cable onto the logic board.

Check the larger caps that are mating with the VBUS of the lightning connector on the logic board for a voltage.

[mon2]

Re: iPad mini 1 - OL on PPVBUS_CONN

See attached. From my paid database which they call as resistance readings. However, believe these are DIODE readings.

Meter in DIODE mode -> red meter lead (yes red) to ground.

Black meter to point to test.

Check the readings against this chart and post your updates.

update- check the voltage to ground @ L5700. Do you see 5v from your USB power adapter ?

[Jenzo]

Re: iPad mini 1 - OL on PPVBUS_CONN

Sorry, went to bed yesterday ^^

Measured the connectors, all have the same reading as the chart you provided.

I have 5v on L5700, the dockingflex should be fine.

What I am wondering about atm is Q5701. I have 4.6v on pin4, the gate, but if I'm reading the diagram correct it should be <4.5v to let the mosfet pass trough power. Or am I reading this wrong?

[mon2]

Re: iPad mini 1 - OL on PPVBUS_CONN

Yes, P-channel requires a lower gate voltage than what is being passed between source & drain pins to enable.

What are the voltage readings on each side of R5704? The 2*resistors on the gate are creating a voltage divider.

If the bottom resistor is a logic low, then the voltage at the gate will sink down enough to enable the P-channel mosfet. Also remove all power and confirm the resistance of the voltage divider resistors on the gate of this P-channel mosfet.

While you are doing resistance checks, check the resistance of this mosfet as well:

Source & drain
Source & gate
Gate & drain

[Jenzo]

Re: iPad mini 1 - OL on PPVBUS_CONN

I got it! Been going at this all wrong. One of the feedback lines was damaged, so the iPad went into overcharge protection

Thank you for the assistance! This has been a very learnable experience once again!

[mon2]

Re: iPad mini 1 - OL on PPVBUS_CONN

Good job! Thanks for the update. Will update this thread once our ipad air 2 is repaired which sure is pointing to the pmic fault. Not too many public posts on this fault but found one youtube video.

[Jenzo]

Re: iPad mini 1 - OL on PPVBUS_CONN

Thank you! Good luck with that, PMIC doesn't seem fun to change, I hope it goes well!

I'll be working on another iPad (2019 model) that bootloops