Lenovo ThinkPad Edge E530 only posts with fan unplugged

[tk1]

Hey all,

Here is what's happening:
Laptop - Lenovo ThinkPad Edge E530, Core I5
Turns on but no POST. (sometimes after several tries it might POST but it is random)
If I unplug the cooling fan, it causes an error and laptop POSTs right away every time.
I can plug fan back in once laptop is running with no issues. Fan works fine.
Bought new fan just to be sure and same issue even with new fan.


Have already completely disassembled laptop.
Tested for POST after removing/unplugging each individual component.

Any ideas? Thanks

[poot36]

Try updateing the bios or reseting it.  Also check that the cmos battery is good.  I have seen some computers that would refuse to post without a good cmos battery.

[Rasz]

Turns on but no POST. (sometimes after several tries it might POST but it is random)

how many drinks have you spilled on it? intermittent most likely means corrosion
take it apart, make few detailed photos, look for copper pads with brown/pink discoloration and grey solder joints.

[poot36]

1+ for liquid damage.  It could also be damage from a drop as well.  I have learned the hard way that well most laptops do start working better after cleaning the liquid damage up I have had one that went from working just fine to turning on but no video output so be warned.

[tk1]

I tried updating and resetting bios - still the same.
No liquid damage as far as I know.
Heat sink was very clogged when I received it. Cleaned heat sink and installed new fan.
Will turn on with charger plugged in (usually takes 2 tries). Will not start up with just battery.
I have seen many other people post same issue even when their laptop was new.
Still weird that unplugging the fan will allow it to boot right up.
Thank you for replies.

[amyk]

Google "LA-8133P", that seems to be the schematic for it. Looks like the fan is driven directly off the +5VS rail and has tach/PWM signals connected to the EC. You can try disconnecting the PWM/tach (probably will cause fan to run at full speed) and see if that works... it could be a corrupted EC firmware.

[Rasz]

No liquid damage as far as I know.

there is never any liquid damage, that is until you show your client actual corroded PCB, then they miraculously remember that one time

look for pink/brown vias, and grey solder joints.

[poot36]

Here is a few other water damage colors that I have seen, white fuzz or just a flat white over the affected location, black on the pins of components, sometimes green but not as common.  Try cleaning the entire board with alcohol and a stiff bristled brush and using compressed air to dry it off it may still work.  Also try it with the original fan if it still works your replacement could be faulty and I have seen bad fans cause bootup problems before.

[MiataMuc]

My Lenovo R61 didn't booted without the fan running (it was clogged..). I find it funny that this one starts without the fan?

[grumpydoc]

Is the fan pulling a power rail low?

It might be working because once booted the fan management kicks in and it won't be trying to turn the fan very quickly - just after power on the fan is often  running at full speed.

Is the new fan the correct type for the motherboard.

[Po6ept]

Many BIOS have a "Stop on errors" setting that you can disable.  The BIOS may be halting startup if it sees a CPU fan error.

[grumpydoc]

Many BIOS have a "Stop on errors" setting that you can disable.  The BIOS may be halting startup if it sees a CPU fan error.

True but the OP said it boots with the fan disconnected despite reporting the fan error.

It might be worth getting one of the POST code display widgets and seeing if that sheds any light.

[Rasz]

It might be worth getting one of the POST code display widgets and seeing if that sheds any light.

and capturing that 5V rail during startup to see if it sags
my bet is still in liquid damage, or bad caps in one of the inverters

[tk1]

I disassembled again. Fully cleaned the motherboard, it was a bit dusty. I didn't find any evidence of liquid damage. Made no difference.
5v rail reads at 5.3v-5.6v before fan kicks on. It reads a steady 5v once fan kicks on.

Google "LA-8133P", that seems to be the schematic for it. Looks like the fan is driven directly off the +5VS rail and has tach/PWM signals connected to the EC. You can try disconnecting the PWM/tach (probably will cause fan to run at full speed) and see if that works... it could be a corrupted EC firmware.

I disconnected the PWM and tach. Laptop booted right up with fan on high but of course got fan error.
I downgraded the bios to older version and it will now boot on every second attempt with only battery. Before it would only do this with adapter plugged in.
So, that is where I am at. Will always boot on second manual attempt, will run all day long with no problems. Will boot fine on a restart as well. It just will not boot up on first attempt.
Any other ideas?

Thanks again.

[sunnyhighway]

Any other ideas?

Try booting from different power-source configurations, battery, power-brick, both.
See if it changes the behavior.

[amyk]

Try connecting only one of PWM and tach, see how it behaves.

I suspect EC firmware corruption or damaged EC.

[tk1]

It will boot with PWM connected and give fan error.
With tach connected it suffers the previous issues.

[Rasz]

5v rail reads at 5.3v-5.6v before fan kicks on. It reads a steady 5v once fan kicks on.

before and after doesnt matter much, its the moment boot fails, capture it with a scope and look for the dip

check C2503 R2451, maybe EC_TACH is shorted to ground/3vs

there are special external programmers for KB9012 which leads me to believe bios upgrade doesnt flash its internal eprom