Question Alienware Alpha R1

adconley95

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Hello everyone!


I've embarked on an interesting quest.

I have recently received an Alienware Alpha R1 i7 4765T version. They're decent at best of a device but struggled with thermal throttling issues. So I've decided to do something about that.

I'm doing some testing before I drop 16GB of RAM, 2TB SSD, EGPU, etc.

I have a Noctua NF-A12x25 5V PWM fan running to an Adapter into the motherboard. I'm getting a CPU Fan Failure on boot.

The factory fan runs a 5V @ 1.10A and the noctua runs at 5V .26A

I'm wondering if the noctua has a different pin out (so power is the ground vice versa) setup compared to OEM? The fan also doesn't spin until I give it a push and it also twitches when its stopped. How does this motherboard control the fan headers? There's no features in the BIOS to edit fan speeds or disable them.

I'd say the power and ground are working properly but maybe the Tach and PWM are backwards? I don't mine chopping of the harnesses to make it work as long as there was accuracy.

- - - - - - -

OEM CPU FAN: PVB070E05N-P02

Noctua Fan: B07DXQTCK6

4 Pin Adapter: B07Q5BTTDX

- - - - - - -

View: https://imgur.com/0478lOj


View: https://imgur.com/vmFPmtt


View: https://imgur.com/ufIKoOv


View: https://imgur.com/MRbCiAs
 

Unolocogringo

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The adapter you used for connecting the fan may be the problem.
Most Noctura fans come with a low voltage adapter. Not an extension cable.
2 options.
Check the bios to see if you can calibrate the fan PWM.
If not purchase a regular fan extension, not low voltage adapter.
You can check to see if the fan runs properly by connecting it directly to the motherboard without the extension.
 

ElectrO_90

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I very much doubt they would change the pinouts because it's pretty much standard.

I'm curious why its 5v, I thought the headers were all 12v and if you want 5v you have to get that from your psu/molex

I'd say the noctua CAN run at 5v, but needs the 12v to "jump start" it. Like a car, when it starts up, it needs extra revs to start, but once started, it idles lower.
 

adconley95

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The adapter you used for connecting the fan may be the problem.
Most Noctura fans come with a low voltage adapter. Not an extension cable.
2 options.
Check the bios to see if you can calibrate the fan PWM.
If not purchase a regular fan extension, not low voltage adapter.
You can check to see if the fan runs properly by connecting it directly to the motherboard without the extension.
Mine did not come with an adapter, I may have to just plug it into USB. I might start with that. I'd love for the fan to change speeds based on temps though.

Unfortunately there are no settings in BIOS regarding fans.

I bought the 'extensions cable' as an adapter not to make the cable longer, I guess there are two types of 4 pins. Large and small. The noctua fan is large and the MB is small. Maybe you can link the Low voltage adapter


I very much doubt they would change the pinouts because it's pretty much standard.

I'm curious why its 5v, I thought the headers were all 12v and if you want 5v you have to get that from your psu/molex

I'd say the noctua CAN run at 5v, but needs the 12v to "jump start" it. Like a car, when it starts up, it needs extra revs to start, but once started, it idles lower.
That was my assumption that most headers are 12v, I did struggle to find a fan and this $20 noctua fan was my only option regarding 92mm and 5v.

The fan is designed to run at 5v
 

ElectrO_90

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That was my assumption that most headers are 12v, I did struggle to find a fan and this $20 noctua fan was my only option regarding 92mm and 5v.

The fan is designed to run at 5v
I guess you don't have a multi-meter to check the voltages or anything like that?
If you do, attach the old fan cable - cut the fan off, strip the wires and then put that on the board and monitor the voltages
 

adconley95

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I guess you don't have a multi-meter to check the voltages or anything like that?
If you do, attach the old fan cable - cut the fan off, strip the wires and then put that on the board and monitor the voltages
Not a bad idea, I'll try that when I get home.

I'm thinking its a power issue, the OEM fan cable is 3inches roughly. My new setup including the fan and the adapter cable is probably +6 inches.
 

ElectrO_90

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There is neglible power loss over 6inches of copper at 5 volts.
To put this in perspective
1000BASE-T uses all four pairs bi-directionally using hybrid circuits and cancellers.[11] Data is encoded using 4D-PAM5; four dimensions using PAM (pulse amplitude modulation) with five voltages, −2 V, −1 V, 0 V, +1 V, and +2 V.[12] While +2 V to −2 V voltage may appear at the pins of the line driver, the voltage on the cable is nominally +1 V, +0.5 V, 0 V, −0.5 V and −1 V. Which is guaranteed upto 100m
 

adconley95

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There is neglible power loss over 6inches of copper at 5 volts.
To put this in perspective
1000BASE-T uses all four pairs bi-directionally using hybrid circuits and cancellers.[11] Data is encoded using 4D-PAM5; four dimensions using PAM (pulse amplitude modulation) with five voltages, −2 V, −1 V, 0 V, +1 V, and +2 V.[12] While +2 V to −2 V voltage may appear at the pins of the line driver, the voltage on the cable is nominally +1 V, +0.5 V, 0 V, −0.5 V and −1 V. Which is guaranteed upto 100m
Ok thats pretty cool. Thank you. The noctua fan requires less amps so how would that play into effect when the OEM requires more? Should be easier to power the noctua correct?

So you're thinking the fan header is 12v? Then why would the CPU fan sticker and replacement parts advertise as 5v? I'm not questioning you in a negative way, just trying to understand.

Thank you.
 

ElectrO_90

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As I understand this is a reference design here - http://www.interfacebus.com/ATX_Motherboard_Fan_Connector_Pinout.html
I think it would be strange to change, but it is a custom system.
The only way to be sure is to measure the voltages. I'm not questioning that its 5v, it's just unusual if it is.
The voltage drop shouldn't even come into it really. As for the power draw, if the system needed 0.5amp to start (because it monitors the draw) then the fan is not drawing enough to start it up either.

NOTE - just realised this is probably a laptop motherboard which is why it maybe 5v - not confirmed, theory
 

adconley95

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As I understand this is a reference design here - http://www.interfacebus.com/ATX_Motherboard_Fan_Connector_Pinout.html
I think it would be strange to change, but it is a custom system.
The only way to be sure is to measure the voltages. I'm not questioning that its 5v, it's just unusual if it is.
The voltage drop shouldn't even come into it really. As for the power draw, if the system needed 0.5amp to start (because it monitors the draw) then the fan is not drawing enough to start it up either.

NOTE - just realised this is probably a laptop motherboard which is why it maybe 5v - not confirmed, theory
I like where you're going with this, definitely a pin check would be the best option as of now

Here is the MB http://www.ascendtech.us/dell-alienware-alpha-r1-mboard-j8h4r_i_mbdktpdellj8h4r.aspx
I was having a hard time finding anything out about this motherboard. Maybe you have better resources?
 

Unolocogringo

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The noctura fans can run down to 5 volts.
It needs at least 7 volts to start. once started it will run at 5 volts.
The low voltage adapters use 12v+and5v+ to get 7v+.
Might be an option, you probably dont need more cooling than that and the fan would be near silent.
 

adconley95

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The noctura fans can run down to 5 volts.
It needs at least 7 volts to start. once started it will run at 5 volts.
The low voltage adapters use 12v+and5v+ to get 7v+.
Might be an option, you probably dont need more cooling than that and the fan would be near silent.

Thank you for the reply, I don't think I understand. Is the low voltage adapter the big pin to small pin 3 inch cable you're referring too? This fan is strictly designed for 5v so I don't think it would look for anything higher than 5v
 

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