A1707 20Vs works, faulty left charge port

[Stephen]

Faulty left charge port, both ports do not work, swapped out port with good one no life on this side, no water damage. Board turns on and fully functions and charges on right side. So this rules out USB C chips etc. I am not seeing any power on both ports on the left side on J3300. Replaced diode that had solder balls under it and still no life on this port. Any suggestions would be great thanks!

[Stephen]

Re: A1707 20Vs works, faulty left charge port

I am leaning towards a faulty Chip on U2800 but correct me if I am wrong

[mon2]

Re: A1707 20Vs works, faulty left charge port

Review fuse F3000 / F3001 / FB200 / FB201 - whichever is applicable for that side of the logic board.

[Stephen]

Re: A1707 20Vs works, faulty left charge port

all fuses not blown

[Stephen]

Re: A1707 20Vs works, faulty left charge port

Any suggestions?

[mon2]

Re: A1707 20Vs works, faulty left charge port

By default of all power delivery products, you must see 5 volts being delivered by the external power adapter.

Mate to each USB-C port (do also test the 180 rotated orientation) and confirm that you are able to see 5 volts at the end of the local fuse(s).

If not, someone is shorting that Vbus rail. Remove all power. Measure the resistance to ground at the local fuse(s).

[Stephen]

Re: A1707 20Vs works, faulty left charge port

No voltage on J3000, computer turns on on other side 20volts and working fine. No power to fuse I guess I should check VBUS rail.

Measured F3001. Definelty a short but fuse is not blown. I am getting randoms drops and reads consistently. 1.80 to 60 and repeats, tested donor board that has good fuses not blown and they show perfectly at 333.00. Tested FB200 and it shows 333.00 so makes sense why that side turns on for both those fuses.

[mon2]

Re: A1707 20Vs works, faulty left charge port

Tested FB200 and it shows 333.00

I am not sure I follow this sentence. Is this the resistance to ground measurement? If yes, what is the unit of measure? 333 ohms?

Apply the units of measure in the posts.

When measuring the resistance, be sure that there is not power to the board and no battery either.

Where you are missing the voltage on the bad side of the logic board, measure the resistance to ground at the fuse and post the measurement with units so we are clear. The fuses are often high current fuses so while you have a short condition, it appears that the current consumption is not exceeding the fuse trigger value.

[Stephen]

Re: A1707 20Vs works, faulty left charge port

sorry 333k ohms

The other fuses go from 1.80k ohms to 60k ohms and just keeps repeating itself.

This is the measurement of F3001 that is dropping and repeating. The 333k ohms is the good side fuses.

[Stephen]

Re: A1707 20Vs works, faulty left charge port

F3001
PP20V_USBC_XB_VBUS_F 180K ohms
PP20V_USBC_XB_VBUS 109K Ohms

FB200
310K ohms on both sides

Update: The bad side fuses are not repeating now, just staying at 180k ohms to 220 range
(normal readings need to be 330k ohms)

[mon2]

Re: A1707 20Vs works, faulty left charge port

Connect the external type C power adapter onto the non-working side.

Meter in DC volts mode (20v or higher scale is ok).

What is the voltage to ground @ F3001 ? Is it stable?

[Stephen]

Re: A1707 20Vs works, faulty left charge port

No voltage whatsoever at F3001 when plugged in.

[mon2]

Re: A1707 20Vs works, faulty left charge port

Check each side of F3001. Then do the same at fuse F3000.

[Stephen]

Re: A1707 20Vs works, faulty left charge port

Yes, I have checked both sides of F3001 and F3000
Both fuses have no voltage whatsoever on both ends of each fuse. Tested multiple usb c adapters and they do not turn on on both ports. Use adapters on other side and power is cycled and computer turns on. I would say faulty USB C chip but then if that was the case the computer would be 5volts on the good side and that would be easy to replace the USB C chips

[mon2]

Re: A1707 20Vs works, faulty left charge port

Mate a USB Type C meter between the power adapter and the defective port(s).

When you apply the power (suggest a power bar on/off so that the connections are 100% stable onto the type C port) - does the meter show a voltage & current draw or does it go dark?

[Stephen]

Re: A1707 20Vs works, faulty left charge port

We are using a USB C type meter its completely dark. No power no voltage reading.

[mon2]

Re: A1707 20Vs works, faulty left charge port

If I recall correctly, this logic board uses a small USB C connector on a paddle board?

If yes, disconnect this paddle board and while it is in the air, mate it to your power adapter. Leave the power adapter unplugged from the AC side - again, suggest a power bar so the type C pins do not cross short.

Then power on the external adapter using the power bar. Does the USB C meter light up as it should or is it still dark?

You should see 5 volts with close to 0A current draw since there is no load from floating USB C connectors.

[Stephen]

Re: A1707 20Vs works, faulty left charge port

Yes that is correct the USB C adapter is a paddle board with two ports. It is removable.

Ok you have me a little confused and I do apologize but I am a little confused what you are suggesting.

The usb c port is removable. I have a USB C meter that will plug into it and it won't turn on but if I use the same port on the other side it will turn on with the usb c meter. please advise.

[mon2]

Re: A1707 20Vs works, faulty left charge port

Something is causing your external in-series type C meter to go dark. Often a short condition. Just trying to rule out who is the guilty party.

Start with using only the external adapter and paddle board -> does the meter turn ON like normal? The logic board will not be connected in this quick test.

If all is well, remove all power. Meter in DIODE mode.

Then red meter probe to ground, yes ground.

Black meter probe onto the paddle board socket on the logic board -> probe each test point and record the DIODE measurement of each test point.

Ground will show 0v but concerned about the other USB connections on J3300 (as an example). Compare the same DIODE measurements with the known to be good and working side. We are checking for defective ESD TVS diodes, etc.

[Stephen]

Re: A1707 20Vs works, faulty left charge port

Meter is still dark. Question would it be a faulty USB C pad itself on the board? I was wondering if these have ever gone bad? I am kind of just confused on this, I replaced all the diodes in question (they had solder balls under them so it showed some kind of issue what was going on) however I still have no power on this port. I am so lost at this point. Have measured Diodes and they are reading correctly from what I am seeing but however you say the ESD TVS diodes. Could you point an example of one of these diodes on this board, I been working on boards all day so now my brain is fried, (brain fog) and we had like 20 customers come in today so been in and out of preparing this board,