Lenovo T440s (NM-A052) dead

[reassor]

So i just got this laptop back after 2 weeks. First time i just cleared cmos and it started now its dead.

I did some preliminary but i found 260 Ohm on L1 (VCCCPUCORE).

Is that dead proc/chipset?

Im asking cause this mobo has me confused to hell.

Got no 3.3v on Bios 8th leg

There is +3 and +5 @ S5

[mon2]

Re: Lenovo T440s (NM-A052) dead

Link or post the schematics for this laptop, if available.

If not available, post clear pictures of the logic board starting with where the external power adapter mates sign the logic board.

The resistance referenced in your post is fine at this time.

Need to confirm that the adapter voltage enters the logic board and how far the voltage continues. The fact that you have some power rails is a good start.

Power down and place your meter in resistance mode (200 ohms). Then check the resistance to ground of each coil. Any super low readings? ( Under 10 ohms)

[reassor]

Re: Lenovo T440s (NM-A052) dead

https://www.badcaps.net/forum/attach...5&d=1603128029

There is schematic. Rail names are so silly wierd,

could not find any low ohms. (will confirm morning when i go to work and actually measure again.

Got 3v at power button. Will check power to this silly 2 chip KBC.

Mainly i was confused that this coil (there is only 1 around CPU) has 260 ohm O_o schematic says its VCCCPUCORE

[mcplslg123]

Re: Lenovo T440s (NM-A052) dead

+19V is definitely reaching the mb as you have +3V/+5V S5 rail present. Resistance on vcore area will be low-so that's fine. You need to check the basic requirement for laptop to turn on. Flash known good bios dump first and dont forget to save your existing bios dump.

[reassor]

Re: Lenovo T440s (NM-A052) dead

+19V is definitely reaching the mb as you have +3V/+5V S5 rail present. Resistance on vcore area will be low-so that's fine. You need to check the basic requirement for laptop to turn on. Flash known good bios dump first and dont forget to save your existing bios dump.

Bios was first thing i did (got it from this forum). 200ohm on cpu is good? (im not that goot at this yet - still lots to learn). Its an i7 Version. Besides this schematic confuses the hell out of me with the naming scheme. will dive into it tooday if i find time.

[mcplslg123]

Re: Lenovo T440s (NM-A052) dead

200 Ohms on cpu is definitely good.

[reassor]

Re: Lenovo T440s (NM-A052) dead

thx cause that was wierd for me. I always measured under 10 on CPU's. Even under 1ohm on GPUs.

Im no expert and it seemed odd to me.

Didnt have time to get to that mobo in 2 days. So much work :O

EDIT:
Read somwhere that 1 of the KBC's (not think engines) likes to die on these boards (it holds all serial numbers and stuff. Ill buy some mobo with broken cpu and will work off that

[mcplslg123]

Re: Lenovo T440s (NM-A052) dead

@REASSOR. 4th gen cpu's show resistance in the range of 100-200 ohms and a reading of 10ohms is definitely bad. Newer cpu's like 8th/9th gen cpu's show very low resistance, sometimes even 2-3 ohms.

[piernov]

Re: Lenovo T440s (NM-A052) dead

10 ohms can be ok on some Haswell-H/M CPUs. For Haswell-U it's more like 50-70 ohms (can be higher).
That's with black probe on ground, red probe on ground causes higher resistance IIRC
Skylake/Kaby Lake/Coffee Lake are often around 5-6 ohms but can be a bit lower.
Lowest I've seen is 3rd gen at 1.5-3 ohms (and even a bit lower on iGPU power rail).
That's on laptops, on desktops it can be even lower.

[reassor]

Re: Lenovo T440s (NM-A052) dead

thx. tooday i measured again and it shows around 190 ohm.

Also board draws around 1.5W - very low amps (0.0024? - something like that)

MEC1633L-AUE its getting relatively hot fast.

Thx guys. Will let you know ehn i figure out how to dump whats in this kbc and send it to a dude who sells those with your code.