a few questions re. x220 fan replacement

[naltar]

Hello,
A fan on one of my daughter's x220 has died (or, at least, runs unbelievably quiet, with no outflow ). Laptop still works, runs v. hot, of course. I bought a couple of _used_ replacement fan+heatsinks off ebay (some new ones are priced at something around 100gbp mark, and I don’t want to wait a month + on aliexpress either.
Seller claims his stock is checked, and I have no reason not to believe them but, given disassembly is a bit of a pain (plus, I’ve never done it, so I’m pretty nervous, despite numerous videos), it would be great if I could test if the fans do work, before I gut the x220. The fan/heatsink assembly comes with this tiny, 4 coloured wire connector, my question is, is there any way to test the fan, with something like an AA cell and some wires, or similar? (I can see that the fan is DC 05V, 0.30A). However, unless I unpick (and resolder) the wires from the connector, presumably there is no other quick way but to to plug it into the motherboard and re-assemble the laptop?
Another question, re. thermal paste/grease and pads, I saw in some videos, that people apply just the paste (after cleaning the cpu, etc.) on the cpu, i.e. no pad, but they put the pad against the gpu (presumably, you don’t need paste when you use the pad?). My question re. paste and pad, is this a recommended way (paste on cpu, pad on gpu), or is it horses for courses, and one of those subjects, people will argue for ever? (btw, I’ve got a 1 mm pad). What was the original, factory assemply on gpu and cpu, pads or grease?
And, if I get to the point of swapping the fan, while I’m at it, is there anything else I should do re. cleaning / pasting internally, other than the obvious removal of dust and other… artefacts?

Regards,
n.

[as.nielo]

Paste goes to CPU and pad to controller chip (this is not a GPU, in X220 GPU is a part of CPU die). In case of your laptop thickness of pad isn’t very important, just pay attention it isn’t too thin.

Regarding fitting a fan with 4 wires IDK for sure. My guess one wire (usually it’s white) don’t need to be connected or connected to the ground point. It’s used to control resistance end thus the speed of fan. In X220 voltage applied is controlled on the mobo. Correct me if I’m wrong.

[axur-delmeria]

Paste goes to CPU and pad to controller chip (this is not a GPU, in X220 GPU is a part of CPU die).

Correct. That's the Intel QM67 PCH (Platform Controller Hub), and is the equivalent of the southbridge chip in Core 2 Duo and earlier designs. It handles USB, SATA, and the PCIe lanes for the WLAN slot and the NEC USB 3.0 controller (only on X220 i7 models).

In case of your laptop thickness of pad isn’t very important, just pay attention it isn’t too thin.

From personal experience with an X220, I disagree. Don't get a thermal pad over 1mm thick, unless it's very soft and mushy like the original. But then, is it even possible to know if you're ordering online?

I ordered 0.5mm, 1mm, and 1.5mm thick thermal pads, but the 1mm one was out of stock. The 1.5mm arrived first, and I put it on the PCH chip, but due to the thickness the heatsink doesn't lie flat against the processor, resulting in very high temps under load.
I replaced that with the 0.5mm pad when it arrived and the temperatures returned to normal. Since I wasn't able to get a 1mm pad I don't know how it will fare, but I guess it won't be as bad as the 1.5mm one.

Regarding fitting a fan with 4 wires IDK for sure. My guess one wire (usually it’s white) don’t need to be connected or connected to the ground point. It’s used to control resistance end thus the speed of fan. In X220 voltage applied is controlled on the mobo. Correct me if I’m wrong.

A 4-pin fan uses PWM (pulse-width modulation), wherein a separate pulse signal tells the fan how fast to spin. If there is no PWM signal, the fan runs at full speed. The other signal is the fan speed signal, which is sent by the fan to the laptop's system board in order to determine how fast it spins. Unfortunately I don't know which wire corresponds to which signal, so you'll have to do some trial and error to find the +V and ground pins. You can use two AA batteries in series (+3v total) and some very thin wire (maybe AWG 30 solid wire could work).

[as.nielo]

A 4-pin fan uses PWM (pulse-width modulation), wherein a separate pulse signal tells the fan how fast to spin. If there is no PWM signal, the fan runs at full speed. The other signal is the fan speed signal, which is sent by the fan to the laptop's system board in order to determine how fast it spins. Unfortunately I don't know which wire corresponds to which signal, so you'll have to do some trial and error to find the +V and ground pins. You can use two AA batteries in series (+3v total) and some very thin wire (maybe AWG 30 solid wire could work).

Very nice explaination! I thought it's more simple, just https://en.wikipedia.org/wiki/Voltage-c ... d_resistor connected in front of the fan supply. Cheers

[naltar]

Thank you very much for the suggestions! In the meanwhile, the x220 finally decided that the super-ultra-quiet-(dead) fan is definitely a no-go (fan error, etc.), so I took the first, easy step, i.e. disassembly. To my surprise, I discovered empty space where blutooth card was meant to sit facing centrino wifi (n6205) card. The two cables (antennas?) for bt card, were properly "terminated/taped", but overall this left me somewhat confused, i.e. it was/is a relatively hi-spec x220, i7, with nice screen, so I presumed bt would have been included by default? To be honest, I never actually tested it actually has bt, my other x220s are so hopeless with bt connection (windows) that I gave up on it altogether.
re. 1 mm pad, well, I ordered 1 mm and I got it. I hope that no extra parts are left after re-assembly, and that it... works
Regards,
n.

[RealBlackStuff]

That slot is not for BT but for WWAN.
The BT-module is a small strip along the front, under the palmrest.
Get the X220 manual from the HMM-link above for details.

[naltar]

That slot is not for BT but for WWAN.
The BT-module is a small strip along the front, under the palmrest.
Get the X220 manual from the HMM-link above for details.

sorry, certainly! In the meantime, I did have a closer look at one of the videos and I saw it was a wann card (I'd thought it strange that bt card is so... big!
Yes, I should definitely read up on what's inside and where (I somehow assumed wann card is by the battery, as this is where the other x220 has a sim slot...). Unfortunately, I need to hurry a bit with fan/heatsink replacement in the meantime, cause my daughter's struggling with her online lesson today, with an old(er) laptop and a mobile
Regards,
n.

[naltar]

[cut]

just to report, because sometimes those stories end abruptly half-way before resolution, this one's with a happy ending, i.e. fan installed (yes, it was a long process to disassemble!), but all's been well for over 2 months. I know, for some people fan replacement is a 'meh', but for me, it was probably the most advanced repair I've ever done in my life.
...
now, that same laptop's developed a vertical strip, darn! daughter's demanding a 'propa' (aka new, shiny, [sh***y] laptop. Over my dead body!

Regards,
n.