On Oct 1, 12:50*am, "
wrote:

I have one of these on my workbench and both the fans aren't working,
the switch itself is fine. On inspection it appears that an SMD
component has come off the motherboard, Z1. Whether this was due to
bad soldering or if it's been knocked I can't tell. There doesn't
appear to be any signs of physical damage or heat.
Tracing the circuit shows that the power to the fans was delivered by
this component and I would suspect it was a zener.

If it's in series with the fans, and they're 12V fans, you can reverse-
engineer
the component value. Usually, there WOULD NOT be a Zener in series,
because Zeners fail (typically) in short circuit; it'd more likely
be a limit resistor, or maybe even a thermal-sensing resistor with a
negative temperature coefficient.

I'd expect "ZD" or "CR" markings for a Zener diode.

I'd also expect the component to be rattling around inside the case
somewhere (get a hand lens and do the Sherlock thing...).