The ASROCK A520M-HDV fan isn't functioning correctly.
The ASROCK A520M-HDV fan isn't functioning correctly.
Hello, thank you for your feedback. It looks like your new motherboard isn’t managing to control both fans properly. One fan responds to DC control—its lights dim when it slows—but the other doesn’t react at all. Both are the same model with 3-pin fans connected to 4-pin CHA_FAN connectors. It’s quite noisy, and the controllable fan spins slower than the other. I’m not sure if there’s a fix, I’ve tried asrock a-tuning but it didn’t help. The UEFI version is 1.10.
When linking a 3-pin fan to a 4-pin socket and the motherboard lacks a DC mode for that header, the output will be 12V, causing the fan to run at its maximum speed. PWM controls speed by rapidly switching voltage levels, whereas DC adjusts voltage to regulate speed. A possible fix is using fan connectors with built-in resistors—Noctua often provides such adapters. Alternatively, you can purchase individual DC fans with a potentiometer that lets you modify resistance, thereby altering the fan's rotational pace.
The original 3 pin fans ran at a steady speed. Speed adjustment was done by changing the voltage, which suggests the issue might not be with the fan itself. You could purchase small wire extenders with resistors to reduce voltage and thus control speed. I already have one in my possession, so it seems there’s no easy fix. Possible problems could lie with the individual fan, the connection adapter, the motherboard, or the software. A quick test is to replace the fan with a working one: if it stops working, the fan is faulty; if it continues, the problem is elsewhere. Edited May 20, 2021 by Bombastinator
I see what you mean, and the dim lighting isn't an issue. The main concern is only one fan is being controlled. The settings don't seem to work with the CHA_FAN 1 connector. I've changed them, and it functions normally—CHA_FAN 2 works well, while the one on CHA_FAN 1 runs at full speed. I'm considering connecting both to CHA_FAN 2 using an adapter. Would that affect the motherboard?
Ah. It wasn’t clear if the device was spinning fast or not spinning at all. If it’s spinning, it might still be a faulty fan. However, it’s much less likely. The other fan would have to be of the same model for this to happen. Placing two fans on one motherboard pin isn’t too risky—they can handle it easily, possibly even more. I haven’t tried it before. A standard approach is using a Y connector. It does cost a bit, though even a few dollars. For extra testing, check if the rear area of the fan is the issue: the faulty one should work on the good port and vice versa. Dropping one port might be a simple solution without needing much confirmation.
I believe I've discovered a suitable alternative solution. Both fans function properly when connected to the CHA_FAN 2 connector. (Observe the "2" in the connector.) I've tested BOTH fans using BOTH connectors, confirming the issue lies with the connector rather than the fans themselves. Additionally, I've reviewed the diagram you shared: notice how header 1 indicates 12V (seemingly stable), while header 2 shows variable voltage. This aligns with my findings—header 2 supports DC control, whereas header 1 does not. Please, anyone reading this, proceed with caution; these boards exhibit limited fan control both in hardware and software. Thank you all for your assistance—I'll go ahead and purchase a Y connector or splitter.
My fans don't respond to PWM signals, so I'll keep using the single connector. Even the UEFI doesn't display a control mode for fan 1, unlike fan 2. To be clear, header 1 can handle PWM (though I haven't tested any PWM fans), but it can't manage DC control. Header 2 supports both PWM and DC control. It seems odd that a maker would make this choice, though the manual evidence shows otherwise.