The rear case-fan light is experiencing random on/off behavior.
The rear case-fan light is experiencing random on/off behavior.
Hi guys,
I recently assembled a new PC with the following specifications:
CASE: DeepCool CC560 V2
Mainboard: MSI B550 Pro-A
CPU: Ryzen 5 5600 with Thermalright Assassin X 120 SE RGB Cooler
GPU: XFX Radeon RX 6800
RAM: Aegis G.Skill 3200 16GB
PSU: Seasonic G12 GM 650W
SSD: WD Blue SN580 1TB (system is running on this drive), Patriot Burst 512GB
Everything is functioning well, but recently I noticed an unusual problem.
Occasionally, the back fan light in the case would briefly stop and then restart repeatedly. The fan continues spinning only during gaming and stress tests (Furmark + prime95). It doesn’t occur during idle, and there’s no flickering—just a smooth on/off cycle.
I’ve checked the fan connectors and re-seated them, but nothing seems amiss. I also disabled XMP settings, which seemed to resolve the issue for about a week.
Could this be related to XMP causing instability with the power supply? Or is there another cause? Any suggestions would be greatly appreciated!
What type of fan is it? Permanent LED colors, RGB or ARGB? How is it linked, directly to the MB or via a hub?
the setup includes four 120mm permanent LED color fans. Three are positioned at the front and one at the back. they are linked using three-pin Molex connectors, then directly attached to the MB without a hub, through three-pin connections to the 4-pin system fan pins. the three front case fans are functioning properly.
I have identified several potential reasons:
All LEDs are linked serially to function properly at 12V; a fault in any one would stop the entire circuit.
Since they are designed to operate at the same voltage (up to 12VDC) and 3-pin fans control speed by reducing voltage, it's conceivable that when the fan receives insufficient voltage to run at its lower speed, the LEDs won't receive enough power. They generally only switch on or off, with brightness changes occurring in a square wave pattern rather than due to voltage fluctuations.
Adjusting the fan speed to maintain a steady speed should stabilize the voltage, which may resolve the problem. If all LEDs share the same fan and a fault occurs in one, only that fan might fail while others continue working.
Yes, it would provide increased voltage for the motor as well as the LEDs.
The fan might have at least one faulty diode. Think about the old Christmas tree lights—those were wired in the same way, and if one failed, the whole thing would stop working.