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143 Posts

11-15-2009

Stockholm

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Re: T420s Fan noise Issue

2011-12-30, 5:21 AM
Lenovo now has my laptop so hopefully they'll be able to find something out!
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2483 Posts

04-08-2011

United States of America

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  • Message 772 of 1217

Re: T420s Fan noise Issue

2011-12-30, 5:31 AM

wrote:
Lenovo now has my laptop so hopefully they'll be able to find something out!

I am more interested in trying to find out if the problem is resolved, and they have stopped shipping defective machines.  Have they?

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143 Posts

11-15-2009

Stockholm

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Re: T420s Fan noise Issue

2011-12-30, 5:37 AM
It's hard to tell at this point - I'd have to wait until I get back to my normal working environment in a few weeks.

What I can tell you now:

I received a replacement T420s last week. Here are some details:

1. Significantly later build-date (Dec vs. May)
2. i7-2640 instead of the i5-2540
3. I have the nVidia Optimus in the new unit
4. I have an SSD in the new unit
5. Bios 1.30.
6. AVC fan (like my old unit)

At this point, I don't have the fan problem. But then again, the ambient temperature is significantly lower than my normal working environment. Once I get back to my original environment, I'll be able to compare very easily just by playing an HD video.
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3538 Posts

07-12-2010

Malaysia

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Re: T420s Fan noise Issue

2011-12-30, 7:32 AM

@calkenneth,

Engineering have tested your unit and they said that it was working fine. Thus it was sent to the returned center.

 

Findings below.

---
The customer sent a note explaining the problem he's seeing. He claims that in his native Stockholm where the average inside temperature is 20-23 C (70-74F), the fan will at be around 2000rpm when the machine is idle, will spin at about 4000rpm when watching a video or doing some other intensive task, but when no longer watching the video and just "using the computer normally", the fan stays at 4000rpm.

He states that while visiting the US, the inside ambient temperature is about 16-17C (61-62F), the fan will drop back down to about 2000rpm.


First thing is that I don't know what "using the machine normally" really means; it's a subjective description. Because is this, I used two repeatable, measurable CPU states to do my testing: idle and 100% utilization.

BIOS is 1.30, embedded controller 1.12. After booting the machine on AC to the Win7 preload (customer reloaded the system prior to sending in). I let the machine sit for a few minutes to stabilize. Power Manager scheme was the default Energy Star. Ambient temperature was 74F (23C), on the high end of the customer's Stockholm temperature.

I used our THI fan / temperature logging tool. To run the CPU at full utilization, I used HeavyLoad. I started THI and the fan was at 1960rpm +/- 25rpm. CPU temperature was 35C; ambient temperature was 23C. I then ran HeavyLoad; CPU temps began to rise and as the temp passed through the 40s, the fan speed picked up. 4000rpm was reached when the temp was in the 60s; the CPU eventually stabilized at about 78C with the fan spinning at 4060rpm +/- 30rpm. I then stopped HeavyLoad. Temperatures began to fall, much slower than they rose. When the temp hit 35C, the fan speed dropped to 1960rpm +/- 25rpm. I then connected to the internet via wireless and brought up Internet Explorer and began browsing. CPU temps fluctuated in the low to mid 40s but the fan speed stayed around 2000rpm.

The customer's claim is that in an ambient temperature of 70-74F, the CPU temperature will drop low enough for the fan to spin down. My testing shows that this is not the case. The crux of the issue may be what the customer considers "normal usage".

Note: this is not the issue that many T420s users were reporting. The issue that was investigated, and resolved via BIOS / embedded controller was that even at idle, the fan would ramp up to 4000rpm and stay there. This customer's situation is different since the fan ramps in accordance with CPU temperature.

 

---


I need a T420s which shows that its always on 4k RPM despite idle and does not spin down even though its cooled else I am unable to proceed further on this case.


//JameZ

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107 Posts

06-28-2011

Italia

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  • Message 775 of 1217

Re: T420s Fan noise Issue

2011-12-30, 9:06 AM

wrote:

I received a replacement T420s last week. Here are some details:


At this point, I don't have the fan problem. But then again, the ambient temperature is significantly lower than my normal working environment. Once I get back to my original environment, I'll be able to compare very easily just by playing an HD video.


@calkenneth: are you allowed to keep the replacement unit or they'll give you back your old one?

 

: is volunteering still bound to the U.S.? I would send mine in if it was possible. I think that Lenovo should be able to request items outside the States if there are no other solutions to fix this long standing issue!

 

Besides, I am planning to call Lenovo support during Jenuary asking for a fan replacement, maybe I'll be more lucky!

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143 Posts

11-15-2009

Stockholm

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  • Message 776 of 1217

Re: T420s Fan noise Issue

2011-12-30, 15:56 PM
@JameZ:

That is very very odd. After I viewed an HD (720p or 1080p) video in VideoLan VLC, the fan would stay at 4000 RPM indefinitely, even when idle.

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107 Posts

06-28-2011

Italia

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Re: T420s Fan noise Issue

2012-01-03, 20:54 PM

Besides,

 

JameZ could you ask the engineering team if they can explain why it works on battery? I'd rather have a BIOS that controls the fan as if my laptop was always on battery than this annoying noise!

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3538 Posts

07-12-2010

Malaysia

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Re: T420s Fan noise Issue

2012-01-04, 3:31 AM
@calkenneth,

They tested the laptop and after a while the laptop fan did indeed slow down. Your previous laptop was then shipped off to the return center.

@alexcriss,

My advice is to send your laptop to service center to get the hardware checked and replaced if needed.

//JameZ
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22 Posts

09-06-2011

Columbus, OH

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  • Message 779 of 1217

Re: re: T420s Fan noise Issue

2012-01-04, 15:02 PM
this may be asked before in this. Is there any windows tools to measure fan rpm, temps etc. I have a t420 optimus with i5 2540,
After playing games for 30 mins, the cpu(video) gets awfully. i cant even touch the serial port next to the cpu fan exhaust.
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8 Posts

01-04-2012

USA

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  • Message 780 of 1217

Re: T420s Fan noise Issue

2012-01-05, 3:44 AM
@JameZ

I sent you a PM. I am in the US and willing to loan my T420s to engineering.
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