What should a fan replacement qualification checklist cover?

Twelve checks across five areas: mechanical fit and direction; electrical window, steady and inrush current; PWM/FG/RD behaviour and connector; acoustics and vibration; and thermal validation on the real unit at worst-case duty. Anything not on the written checklist will eventually escape to the field — the checklist is the qualification.

The checklist

Run all twelve on first-article samples, in this order, and record measured values (not 'OK'). Stop at the first red flag — interface mismatches are cheaper to find before thermal validation.

How to run checks 5–8 without a lab

The host controller is your signal lab. Read the tach register at fixed PWM duties; command a locked-rotor by stopping the fan with a non-conductive tool at low duty and confirm the alarm propagates; mate the connector on a production-grade fixture; scope the PWM line for clean edges at your controller's frequency. Each takes minutes and has caught real problems in our sample validations.

• Record duty→RPM at 20/50/100% duty for the map.
• Test RD at both locked and slow-rotation states.
• Check tach pull-up level matches the host input spec.

Close-out

File the record: measured values per check, sample serials, ambient conditions, and the approving engineer. This record is what your customer's quality team will ask for — and what protects you when the incumbent supplier allocates that part away. MEGA Tech provides sample data packs structured for exactly this close-out.