[Help] Dell Inspiron E5440 - Fan Pulsing Issues

[NickLAranda]

Hey, I noticed this happening one day so I bought a new fan:

Still pulses.

How would I diagnose where the fan plugs in to where it gets controlled to check for bad components?

Or, is there another method I can use to figure out why my fan is speeding up, the slowing down every second about?

Thanks.

 

[DVDR_Dog]

I think I can help you out Nick. I work on these models pretty frequently.
First you mention you have replaced the fan. Is that the CPU heatsink and fan? First thing I can tell you is most of the OEM's do a horrible job applying paste to the heat sink and CPU. I would start there because you are almost guaranteed a performance increase. Use 70% or better isopropyl alcohol to thoroughly clean all old paste off both surfaces.
Keep in mind that the only purpose of paste is to fill in the irregularities, the less you use and the thinner the film the better. Paste doesn't conduct heat as well as metal. Dell's CPU heat sinks have numbers related to the order you tighten them, pay attention to that.
Once you have the whole rig tightened back up use software to check the sensors, why I wait is because if the heat sink is wonky you will get inaccurate readings.
For a Dell, hit f12 directly upon power-up and select diagnostics. That will let you see the readings the BIOS receives relative to internal temps and fan speeds. If things are still crazy the only other option I can think of is to install the program "Speedfan". Do a web search, it's freeware from Almico and I think it still allows manual over-ride of automatic fan control. Make sure you monitor your temps too if you go that route, the program allows you to do that as well.
That's what I would do and I have serviced a number of this model (You meant Latitude E5440 didn't you?)
Good luck and let me know how you made out.

 

[NickLAranda]

I'm an advanced tech, 20 years of experience. I for sure changed the paste hahahahah

Dell Diagnostics and POST say the Fan has Malfunctioned [definitely a good fan, works on another machine].

SpeedFan can't this particular laptop :/ I've watched so many "SpeedFan +Dell" setup videos on YouTube lol When I change the speeds, it they max out, like a minute later they spin back down to default speeds.

For more precise narrowing down of exactly what my laptop is, here is the Express Service Code:

34292414054

Lastly, since the fan is still on, using Open Hardware Monitor, I am able to see my pulsing fan temps are around 40-50c idle and 68c when the laptop is on my bad & I'm making a light dubstep loop in FL Studio.

So at least this problem isn't an issue. Yet.

Spoiler

Yes, I wave all liability by volunteering to provide "sensitive personal information" about ONE of the COUNTLESS machines I use {this is NOT a daily driver or a customer's laptop. It's an extra "lug-it-around" do everything machine.} and that I will never seek legal action against the websites this post ends up on, the users who view my information and any administrators, moderators, etc.

YES, you CAN find the HARDCODED MAC address OF BOTH my wifi and ethernet adapters with this information, possibly more info. The warranty is dead, thank you if you purchase one for me ahahahahhaha

But that's why I posted this. I don't care what do you with information about my laptop & I won't hold any person or entity responsible or accountable.

 

[DVDR_Dog]

I'm an advanced tech, 20 years of experience. I for sure changed the paste hahahahah

Longer than that here. If that's what's being reported to the BIOS and you already checked the heatsink you and I know it's a hardware problem. Unless you care to reflow and replace the faulty sensor, live with it.

 

[NickLAranda]

Longer than that here. If that's what's being reported to the BIOS and you already checked the heat-sink you and I know it's a hardware problem. Unless you care to re-flow and replace the faulty sensor, live with it.

I can re-flow, I just got a heat-gun that has a small tip, but I can either order another smaller tip or get a ton of Kapton Tape if I need to mask other components for whatever reasons.

I have tweezers but I need liquid flux.

Where is this sensor? Do you have a schematic for this motherboard?

Do you know exactly what chips I need to probe to diagnose them?

Do you know which componets that I could just replace and guarentee a fix [without a length of how long it'll be fixed of course, due to various other factors that could make this casue this again]?