Input voltage tolerance of Mesa 7i96S

Hey guys, 

I'm using Mesa 7i96S with linuxcnc. To power this board I am using a stepdown buck converter module.
24V power supply->buck converter->Mesa 5V input

But before connecting to Mesa I tried checking the voltage of buck converter by connecting a multimeter.
On 24V smps getting switched off, I see buck converted output varies drastically from peaking upto 16-18v for then dying down.

As per my understanding Mesa can not tolerate this high voltage ? Is there any protection on Mesa 7i96S for overvoltage ?

Pls help.

Cheers
 

The 7I96S has a overvoltage clamp diode but a large input surge that
is not current limited may overheat and damage this diode.

You might check you power supply with a small load, say 100 Ohms
and see if it still has an output overshoot.

sorry... It was my fault.... the reported voltages were in millivolts.... so not an issue.... buck converter is behaving sanely... Thanks