Lenovo t470 Bad pathway

[lofton]

Hello, I was updating the bios on my t470 20jn pf1q6dx5 using the soic8 clip that came with the Ch341A on the bios and pressed the clip too far back when i was taking it out and it knocked off what look like little capacitors, can this be repaired or bypassed with solder or a wire or what was originally on there, they are extremely small. I have attached two pictures, one with the capacitors on and one with them off. It took me weeks to figure out why the board wouldn't power on. I thought I had broke the bios. THe machine turns on for a second then turns off.

[mon2]

See attached - as a confirmation of the work to be done.

[mon2]

The critical parts are the tiny black ones. These will be low resistance resistors to assist in stopping ringing. Values like 33R (ohms). Not super important to have onboard so you can bridge the pads with a tiny piece of solder.

Review the good picture and note the location of the black resistor. Carefully bridge only this area to bypass the missing resistor. This will allow for the signal to travel to this bios once again. Double check your work before powering up.

[lofton]

THANK YOU MUCH, I will try it in a bit.

[mon2]

See attached - as a confirmation of the work to be done.

[mcplslg123]

I dont recommend putting solder blob in place of this resistor. Should be replaced with a resistor between 15-33 ohms. By shorting the resistor pads, it may work but not recommended. Do it just for test purpose only.

[lofton]

See attached - as a confirmation of the work to be done.

WOW THAT WORKED!!!!! Thank you so much!! I just received the replacements boards ( yes it happened two motherboards! 🤦🏾♂️) I see now why people desolder the chip instead of using that clamp.

[lofton]

I dont recommend putting solder blob in place of this resistor. Should be replaced with a resistor between 15-33 ohms. By shorting the resistor pads, it may work but not recommended. Do it just for test purpose only.

Would happen to know where I can get that small of a resistor like the original that was on there?

[mon2]

See attached. Personally am ok with the solder blob but you can replace it with a very steady hand + tweezers and lots of spares

Ok to use a 33R (33 ohms) 0201 sized part here. See attached on the logic of the size of this missing part.

The large flash chip = SOIC8. In reviewing the PCB footprint for this SOIC8, we know that the pin-to-pin pitch = 1.27 mm. This missing part is about 50% of the distance between the 2 pins so ~ 1.27mm / 2 = 0.65 mm.

Based on this length, the missing part appears to be a 0201 SMD sized resistor.

You can buy from Digikey / Mouser / Arrow, etc. or even Aliexpress but faster and still cheap in USA:

RC0201FR-0733RL YAGEO | Resistors | DigiKey
* I would order at least 50 of these tiny buggers as they will go flying across the room a few times
* no coffee / caffeine before the surgery
* practice on donor boards before attempting this repair - best if you have a hot air tool + flux -> apply flux -> use tweezers to pin down the part -> hot air at low air pressure to secure the part onto the PCB pads

PS: If you are proceeding with this resistor sourcing -> grab some 0.1 uf X5R or X7R 0201 caps for the OTHER missing capacitor that is south of this resistor.

[lofton]

See attached. Personally am ok with the solder blob but you can replace it with a very steady hand + tweezers and lots of spares

Ok to use a 33R (33 ohms) 0201 sized part here. See attached on the logic of the size of this missing part.

The large flash chip = SOIC8. In reviewing the PCB footprint for this SOIC8, we know that the pin-to-pin pitch = 1.27 mm. This missing part is about 50% of the distance between the 2 pins so ~ 1.27mm / 2 = 0.65 mm.

Based on this length, the missing part appears to be a 0201 SMD sized resistor.

You can buy from Digikey / Mouser / Arrow, etc. or even Aliexpress but faster and still cheap in USA:

RC0201FR-0733RL YAGEO | Resistors | DigiKey
* I would order at least 50 of these tiny buggers as they will go flying across the room a few times
* no coffee / caffeine before the surgery
* practice on donor boards before attempting this repair - best if you have a hot air tool + flux -> apply flux -> use tweezers to pin down the part -> hot air at low air pressure to secure the part onto the PCB pads

PS: If you are proceeding with this resistor sourcing -> grab some 0.1 uf X5R or X7R 0201 caps for the OTHER missing capacitor that is south of this resistor.

THANK YOU SO MUCH!!!!!!!!!!