S17 APW9+ FAN problem

[Gabrics]

Hi Guys,

We have a few Bitmain S17 units and the 15K RPM FANs in the PSU started to die (~ 1y old). No problem (we thought). We ordered a bunch of 40x40x28mm 12V ~same FANs and installed them (originals and the replacement are both 12V are 2 wire no PWM type).

And here comes the surprise: Original FAN works from a given FAN header (inside the PSU). Replacement FAN doesn't work from FAN header (inside the PSU) (several PSUs and FANs tested).

But the replacement FANs do work from: 12V test PSU; from the 12V coming from the APW9 PCI-E connector.

Voltage measured on the FAN connector ~12V. Voltage measured on wire of the new FAN, ~12V. So the correct (looks correct) 12V is reaching the new FAN, but the FAN just won't work at all.

Now I am stunned. How can a simple two wire FAN not working if correct voltage applied (and working from the same PSU's PCI-E 12V)?

Any idea would be welcomed as these are relatively hard to come by and not that cheap either.

Original FAN: Nidec UltraFlo  W40S12BMD5-01Z90.

Replacement FAN: Sunon PDM1204PQBX-A Double Ball Fan 12v 8w Fan 40x40x28mm.

Thanks.

PS: Please also advise if you know any online store selling two wire 40x40x28 15k RPM fan's and not shipping from China.

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[HagssFIN]

Did you measure the voltage in the fan connector in the psu? What was the result?

Maybe the problem is not in the fan, but in the psu circuit.

[euhctcyn]

The one that you bought should work, is pretty equivalent in terms of CFM/performance/specs:

https://imgur.com/a/TpJJVgG – First graphic is the Sunon specs, second one the original Nidec.

PS: Please also advise if you know any online store selling two wire 40x40x28 15k RPM fan's and not shipping from China.

Why 15k RPM? Afaik the 17 series fans work @ 7k RPM at max.

[Gabrics]

Original FAN works at 15K: http://www.equipment-coolingfans.com/sale-12327231-12v-15000rpm-utra-flow-axial-fan-plastic-frame-dc-nidec-type-w40s12bmd5-01z90.html

Voltage on the FAN pins is a good 12V. 12.23V to be precise.

Yepp, it should work. And it doesn't . We a bought like 50 and none of them work tested in 6 PSUs. I am thinking that they (Bitmain) may pulse the voltage on the FAN pins and that somehow doesn't work with the Sunon replacement FAN (we don't have an oscilloscope at the shop).

We found the problem finally. The FAN pins (two pin one way header!) 12V PINs inside the APW9+ are reversed on the PCB. The original FAN works with the reverses polarity, but the new fan only works if the polarity is correct. Weird.

[euhctcyn]

Good to know, thanks for sharing!