Dead Dell Latitude 5420 not receiving 20 volts from USB-C charger

[bk304]

I gave up. I determined that the short is in the 5V circuit. I removed the PD chip and the 5V regulator. I injected 5V and cranked up the current and nothing much happened. I found one part of a trace on the circuit board that showed up on the thermal image. I could not find any other component that stood out. Usually it's a cap, a diode, or a MOSFET. That would be easy to fix. I don't want to put anymore time into this one. I made a copy of the BIOS if someone needs it.

[mon2]

5v short may be the vbus rail or load switch used by the usb ports.

[facta]

hello GUYS, i would like to ask about TPS65994AD/AE PD controller recently it is becoming a common problem on Type-c connectors. does this require programming before installation or if yes how do we program it. i have several of these new chips from different suppliers but none worked on several models of laptop where they will turn on from a charged battery but fail to power from charger or negotiate 20v . please help.

[mon2]

After a bit of reading of the PD controller by Texas Instruments, the TPS65994AD/AE PD controller can be configured by an external EC over I2C OR an external EEprom.

In reviewing the Lenovo LA-L931P laptop schematic, this PD controller is being configured by an external EEprom. See attached.







Be sure that U15 is properly soldered and is present on your board. From my understanding, U15 is holding the configuration firmware for this PD controller. If all looks well for this controller then perhaps the contents of this standard eeprom is corrupt.

[facta]

well explained and now it is making sense to me using the example provided.

i can confirm that i have u15 properly soldered and am yet to check the status but i believe it is okay and i have downloaded TI customization tool just to get familiar with the interface as shown below.
my next question is which programmer do i use to program this eeprom via I2C bus? i only have CH341A Mini Programmer for the bios and would like to know if this is compatible? lastly is the Dump inside the eeprom useful in anyway during the process of build the configuration file?

the attached schematic is for DELL latitude 5530 and i once failed to fix it with same problem and i want confirm what is written on your TPS65994AD datasheet that sometimes configuration file is stored in an external EC as shown below.

[mon2]

Yes, the 24c256 eeprom should be supported. Only perform a read and save copies of the original to archive the current firmware. Ideally, for testing, you will need a full dump of this eeprom from a known good and working motherboard. Also post this pd eeprom dump in the bios section forum.

[mon2]

On the Dell, the firmware is injected over the i2c lines driven by the EC. Check the bios local to the EC or attempt a full bios reflash of the main bios. This process may apply the current pd firmware. Post all updates.

[facta]

i checked u 15 and it is okay because i have found 3.3v on I2C pins(5,6) as well as pin 8 and i have copied and pasted the dump on BIOS FORUM

so you believe copying the eeprom file from a working laptop will solve my problem? what kind of laptop; same brand or model or any other laptop which has same configuration?


For the dell laptop i returned it to the customer because i gave up after failing three times up until this lenovo came.

however i want to testify that TPS65994AD/AE has two form factor : QFN (48) and BGA (50 pins), the QFN model doesn't require programming because i have replaced them over 10 times in models like lenovo thinkpad t16, T14 gen 3 and i never experience the problem that am having with BGA version and now am interested to learn by understanding this configuration and i appreciate your effort to help me.