Any Idea for repair L13 Gen2 LAR-2 PD Charger Mosfet CSD87501L always Burned

[Mike_Ho]

Dear All

Anybody have experience to repair L13 Gen2 Board Number : LAR-2 PD charger problem?

I have one board the U4201 CSD87501L are burned and the 20V_VBUS_USB2 can't switch to 20V_VINT_IN, after replace this Mosfet it's still very HOT and just use few hours will burned again. i have repeat replace this Mosfet 3 times and all dead.

After that i try to shorted Mosfet Source 1 to Source 2 to bypass the 20V, and found the Control Gate 1 and Gate 2 voltage both are 20v same with 20V_VBUS_USB2.🤨

So did anybody know this case will need to replace the PD Controller IC TPS65994AD ( it have Black epoxy under chip can't reuse after remove ) or it have another parts fail.?

P.S. The Bios are updated to last version.

Thank's a lot.

Best Rgds.
Mike.

[mon2]

Remove all power. Meter in resistance mode. Measure the resistance to ground of 20V_VINT_IN. Post the measurement.

Is the replacement mosfet from a reliable source? It may be to not the same specs. Good sources are Digikey, Arrow and Mouser. Texas Instruments has good and better rated mosfets as well.

[hoeralu]

I'm currently having the exact same issue - TPS65994 replacement didn't solve it.
The laptop is currently back with the owner with new FETs (mine are from Mouser) because I didn't have time for more detailed analysis.
I expect to get it back in about a week with the same issue for the third time, then I can investigate further.

What's weird is that the gate voltages don't reach high enough to fully switch the FETs on, so there's always about 1V VDS which can produce 2.5W on an empty battery.
No wonder the FETs almost desolder themselves.

According to the Datasheet the TPS has internal charge pump for the gate voltages so I can't really measure anything other than gate voltage.

I will keep you posted next time I have the device, please let me know if you find something.

EDIT:
Now that I think about it: The charge pump apparently delivers only 10µA of current, does anyone have experience if excess flux from manual soldering could pull the gate voltage down a lot with that low source current? Might be worth a try to work a lot cleaner, I tend to go generous on the flux...

[MAREBELE]

I'm currently having the exact same issue - TPS65994 replacement didn't solve it.
The laptop is currently back with the owner with new FETs (mine are from Mouser) because I didn't have time for more detailed analysis.
I expect to get it back in about a week with the same issue for the third time, then I can investigate further.

What's weird is that the gate voltages don't reach high enough to fully switch the FETs on, so there's always about 1V VDS which can produce 2.5W on an empty battery.
No wonder the FETs almost desolder themselves.

According to the Datasheet the TPS has internal charge pump for the gate voltages so I can't really measure anything other than gate voltage.

I will keep you posted next time I have the device, please let me know if you find something.

EDIT:
Now that I think about it: The charge pump apparently delivers only 10µA of current, does anyone have experience if excess flux from manual soldering could pull the gate voltage down a lot with that low source current? Might be worth a try to work a lot cleaner, I tend to go generous on the flux...

Hi.

I have this same problem on lenovo yoga 9 do you find the solution?

My pd chip tps65994bf need to be program so I can't replace the pd but I've changed the mosfet 2 time but still hot