Hp z420 very noisy

[Onur919]

I have a hp z420 and the fan noises are very very loud i have changed the transistor the 2n2222 and still nothing changed any suggestions? 

[NonSequitur777]

@Onur919,

Welcome to our HP Community forum!

Thanks for sharing the details -and hat-tip for trying a hardware-level fix! That said, on the HP Z420, the fan speed control is managed by the motherboard’s embedded controller, and if that circuitry is failing or misreporting temps, it can cause the fans to ramp up constantly, even under no load.

 

Things to Try Before Giving Up:

1. BIOS Reset or Update – Try resetting the BIOS to defaults or updating to the latest version if not already done.

2. Thermal Sensor Check – If any of the system sensors are reporting crazy temps (e.g., 100°C), the system will ramp fans as a failsafe.

   • Tools like HWMonitor or Open Hardware Monitor might help identify that.

3. Check Fan Connectors – Make sure fans are plugged into the correct motherboard headers (CPU, system, etc.).

4. Inspect VRMs and Surrounding Area – Heat damage or capacitor bulging near the fan control circuitry might explain the issue.

 

If That Fails...

Given that you already replaced a 2N2222 (probably near the fan control area), and the issue persists, it's very possible the board has deeper issues — either in the fan controller logic or its thermal feedback loop.

Recommendation: Unfortunately, you might want to consider sourcing a replacement Z420 motherboard: used Z420 motherboards may still be available on Sahibinden.com or Letgo Türkiye — cheaper than importing.

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The Z420 is still a solid system when running properly!

Kind Regards,

NonSequitur777