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Old 12-13-2021, 01:46 PM   #3
reformatt
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Join Date: Feb 2020
City & State: Noosaville
My Country: Australia
Line Voltage: 240V 50hz
I'm a: Professional Tech
Posts: 309
Default Re: Quanta X31 DA0X31MBAF0 Schematic

I have fixed one of these recently with problems with the USB C ports. It's a shitty design. These are used to charge the laptop. So if both fail, you pretty much have a dead lappie.

There are 2 ports, CN1 and CN2. The connectors use a combination of through hole and surface mount pins, the latter of which are concealed under the connector. The strain relief for this connector is just the grounding lugs on the PCB. Given that you have the AC adaptor being plugged into them on a daily basis, chances of physical damage are quite high. The supplied adaptor was iffy at best, so likely owners will wiggle these cables to get them to work. This increases the chance of pad damage under the connector greatly.

In this case, CN1 was not working at all and CN2 worked when the cable was plugged in one direction only. Both connectors were removed, CN1 was ok, however 3 of the concealed pads were ripped off the board. Replaced both, have 20V on CN2 when connected, but zero life on CN1. Probing around, I found a short on TBTA_CC1 of U13 (you can check it on C47). Removing the IC removed the short. I installed a new TPS65982DA and working again. CC1/CC2 are the connection sense pins to tell the other end to switch on the port.

It's worth mentioning that the DA suffix is very important here for this IC. I wasn't paying too much attention when I ordered them. The TPS65982 chip I installed worked, however there was no 20V on either port with that installed. Wasn't till I went to look at the datasheets that I realised I had f---ked up. So like the CD3215's, you need both of these chips working to get your negotiated 20V.

Don't use low melt on the USB C connectors (like I saw NorthridgeFix do) as you will likely rip the concealed pads (as these will still have lead free on them). Heat from the opposite side of the board to these pads and only nudge the connector when the lugs are molten.
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