SMART Board 4065 sound issues

[TechMofo]

Hey guys,

 

We have a SMART Board 4065 connected via HDMI to a Dell Optiplex 3240 that's been having randomly occuring issues with sound.

 

When you login in the morning, sound works without an issue, however once the teacher logs out/machine locks, the sound completely goes.

 

I've tried disabling/enabling the sound card, to no avail. The only fix I've discovered so far, is to restart the machine, which is a massive inconvenience if this happens mid-lesson!

 

We have a second 4065 hooked up to a 3240, and this issue has never occured, does anyone have any ideas!?

 

Cheers