Apple iPad Pro 12,9" 4Gen no charging, but working fine

[waterchill]

Hey folks, I have this iPad Pro 12,9" 4Gen A2232 here with no charging issue. The main fault was a crossed pins / faulty USB charging port due a bad cable.

So I started to replace this parts:

- replaced usb-c port -> no result
- replaced battery -> no result
- replaced usb-c chip CD3217B12A -> no result
- replaced 343S00326 -> no result
- replaced 343S00327 -> no result
- replaced 343S00328 -> no result

I have no more ideas for this issue. There is no short on the whole board, and the iPad is working fine with battery. Also no connection with cable to PC. Any ideas on this?

Regards

[mon2]

Would you have a USB Type C meter? If not, check your local Amazon stores. Be sure it is a bidirectional type.

Share the voltage and current draw of the target iPad.

If shopping, does not hurt to consider a USB Type C breakout board. It can be used in DIODE mode to confirm the status of the USB Type C connector / pinout / wiring to the logic board.

[waterchill]

Yes I have a "Mechanic" USB-C and lightning Tail insertion tester. After changing the usb dock it said some faults. After changing the usb chip CD3217B12A it says everything is ok. All values are normal and exactly same as an other iPad with usb-c. The current drwa if you plug in an USB-C cable from USB-C charger is 0,000A it only switches to 5V. From USB-A charger also 0,000A. I have also a breakout board, but all values are ok.

[mon2]

Flip the USB Type C cable by 180 degrees. Test again. Still 5V @ 0A current draw?

5 volts is a default, power on voltage by the power delivery adapter. After a proper communication over the single wire CCx line, the logic board will negotiate the 20V power delivery contract out of the power adapter.

At 0A, you have no load. Is it exactly 0A or a few mA. This is important to know.

I have also a breakout board, but all values are ok.

Which values? Post each diode mode measurement and pin number under test. Without measurements, we will be guessing.

What is the origin of the CD3217 PD controller?

When you dock the power adapter to the iPAD, do you hear the usual wake up chime that the USB port has been plugged into a power source? That is when the screen lights up and usually shows a battery graphic.

[waterchill]

Flip the USB Type C cable by 180 degrees. Test again. Still 5V @ 0A current draw?

Same result, 0A current draw

At 0A, you have no load. Is it exactly 0A or a few mA. This is important to know.

I'm using a power supply Aixun PS3208 and I know that between 0 and 5mA it will show 0mA. So I cannot say exactly. Can you point me a better way to measure this exactly?

Which values? Post each diode mode measurement and pin number under test. Without measurements, we will be guessing.

Same as the USB-C checker. The USB-C checker give same result +/- 0,01V as same functional iPad on each pin

What is the origin of the CD3217 PD controller?

Aliexpress

When you dock the power adapter to the iPAD, do you hear the usual wake up chime that the USB port has been plugged into a power source? That is when the screen lights up and usually shows a battery graphic.

Exactly nothing happens when plug in cable.

[mon2]

You are not drawing any current. Be sure that the USB-C paddle cable is firmly seated onto the main logic board. Do this confirmation without the power adapter attached. The B2B mating must be firm, otherwise, this cable is just 'floating in the wind' so there is no load = 0A current draw.

[waterchill]

I know exactly what you mean. I have tried 2 different usb connectors also tried not to install this in the iPad case because it is easier to connect it. But all this without result and the usb-c checker would not give me a good measurement. I can alsomeasure on the board some voltages with connected usb cable and disconnected battery.

[mon2]

Interesting tool. Have not seen this one yet. Will investigate it later.

Remove the USB connector paddle board / cable. Remove all power. Meter in DIODE mode.

Carefully measure each pin in DIODE mode to confirm their values. Do not worry about the ground pin checking but interested in RED color pin. Your BV diagram will offer the locations of each non-ground pin.

With no power -> meter in DIODE mode -> RED meter probe (yes RED) to ground & Black meter probe to the point to test.

Post the table of values.