[BPI-R4] Supplying power through USB PD stopped working

Banana Pi Router design BPI-R4(MT7988)
1

I somehow managed to brick the USB PD port on my R4.

It was working earlier today, then I was unscrewing some things and checking my NVMe SSD, because it wasn’t being detected. When putting the R4 back onto the spacers (which surely was a dumb thing to do, while the board was powered), I shorted something which made the R4 reboot.

The next time I reconnected the USB plug, it didn’t power on. First, I thought my whole board is broken, but I found a 12V power supply with the right plug and when using that, it powered back on.

I also tried something else. Using a FNB58 USB tester, I forced the PD power supply into delivering 12 or more volts (options are 12/15/20, but it always worked with 12), which also made the R4 boot again.

So, my assumption is, that I somehow broke the PD communication chip when I shorted something on the board. Anyone got an idea how to fix this or had a similar issue? I guess the only solution is to replace the chip. :roll_eyes:

2

First view said, it is the CH224K

grafik
grafik2687×665 59.5 KB

grafik
grafik1577×920 58.4 KB

The chip should be located beneath USB-C Port:

grafik
grafik1339×1557 131 KB

This is without promises!

3

Big thanks Michael!

Thanks for digging that out of the data sheet for me.

I already found a distributor for a replacement chip. The chip costs less than 0,50€, but ordering just one or two adds a handling and decent shipping fee. :sweat_smile:

Only thing I couldn’t test yet are the signals from the chip through a multimeter. My FNB58 only shows an oscilloscope for the USB VBUS channel, but not for the two CC channels PD uses. Because it could just be, that one of the resistors on the R4 handling the pin inputs is defective.

4

You can measure over the resistor when board is off and check their value…maybe you have only broken solder point? Or usb connector has issues? Have you looked if you can measure voltage directly on connector?