Electronics > Repair
Can this Noctua 12v Fan be fixed?
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fzabkar:

--- Quote from: enut11 on July 31, 2024, 02:08:01 am ---It's a Q. Similar to your URL.
--- End quote ---

Then it's probably an RK7002 by Rohm:

https://avtronic.eu/medias/rk7002/rk7002.pdf
fzabkar:

--- Quote from: enut11 on July 31, 2024, 01:56:58 am ---There is 5.6R resistance between 4 (+IN) and 6,7 (Gnd).
--- End quote ---

ISTM that if V1 and V2 are shorted to ground, then the IC has a shorted internal MOSFET. Is that the case?
magic:
The discrete circuit seems to short the negative terminal of the supply bypass cap (C1) to ground after a time delay determined by R5,R6,C2. Is it supposed to limit inrush current? :-//

At any rate, this part doesn't seem particularly critical and most likely the IC is blown. If R5 measures 3k3 then the supply can only be shorted by the chip or by C1. Easy to check by desoldering C1.

edit
"Shorted by the chip" could either be internal short between VCC and GND or shorted power transistors in series with motor windings, as suggested by fzabkar. Maybe 5.6Ω is simply winding resistance and the chip has about 0Ω from V1/V2 to GND...
enut11:
Both R5 and R6 measure 1.65K in circuit.
It is a nuisance when manufactures use custom chips, especially in what would otherwise be a valuable and repairable item.
thm_w:

--- Quote from: enut11 on July 31, 2024, 01:15:38 am ---
--- Quote from: thm_w on July 31, 2024, 12:14:05 am ---This fan was released in 2018 or 2019, warranty 6 years, surely it was still under warranty?

--- End quote ---

I am not the original owner and do not have the receipt. Also, cost of postage from Australia could exceed its value.

--- End quote ---

They are not going to ask you to mail it back.
https://www.reddit.com/r/Noctua/comments/st4vb7/noctuas_amazing_warranty_services_secondhand/
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