820-00239 no charge on one of the USB-C's

Revive

Member
Board is clean, no liquid a or signs of drop damage. Everything seems to work well except the back left USB-C port does not charge the battery or power the computer, though it works fine as a data port.
The other 3 USB-C ports take a charge and operate normally.

I'm assuming this has something to do with the PP20V_USBC_XB_VBUS?
I've checked the bank of relevant caps around it and resistance seems fine. tried another I/O board, no change.

Any idea what the usual suspects are for USB-C charging issues?

Many Thanks
 

JohnB8812

New member
The CD3215 that controls that port is very likely bad or has a cracked ball under it. Which port is it exactly that doesn't work?
 

Revive

Member
It's the USB-C port where the charge port used to be, top left when viewing the laptop normally. Its probably the jack that was used most for charging because of its legacy positioning.
The weird thing is that all the other ports work correctly I thought if there was problems with the CD3215 it would show up in both ports?
 

JohnB8812

New member
In most situations, YES a bad CD3215 will cause all ports to cease functionality. I have found that a partially bad CD3215 will allow ports to work except the one that it corresponds with. Take at U3100 and U3200 for any signs of corrosion or bad components. Diode mode the PP3v3_G3H rail as well as the LDO rails near each CD3215. My guess is either U3100 or U3200 will have a low reading for PP3v3_G3H near the chip.
 

2informaticos

Administrator
Staff member
First of all you must check voltages on the board when you connect charger to that port.
Usually SMC doesn't allow PPBUS_G3H if detects USB-C controllers problem
Maybe that controller doesn't receive charger voltage at all, SMC thinks is in battery mode then.
 

Revive

Member
Okay so the port started to work intermittently, reading on the PPBUS_G3H look normal, and diode mode readings seem to match across all four IC's, I did notice the Q3200 is getting really hot and I'm pretty sure that's the issue which makes sense.
My question is whats the best way to deal with these underfill chips in close proximity to the rework area? lots of Kapton tape and frugal with the flux? Any other tricks or techniques?
 

JohnB8812

New member
Best thing to do is put a heatsink over them (quarter, iPhone shield etc) and to not blow hot air directly at them if possible.
 

Revive

Member
Replaced Q3200, area no longer hot and the port's is now getting 20V, but the port only works when the USB-C is plugged in one way, if I take the plug and flip it over and plug it in "upside down" I get nothing, not even 5.2V. Not sure if this was happening before (though I didn't think so) had never even thought to look for it.
Is it fair to say this is a U3200 issue? what specific lines have to do with USB-C orientation?
 
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