75 series Troopie cabin filter

We've had several 75 series troopies and they don't have cabin filters.

Cabin filters have only appeared in the VDJ series vehicles.

Thanks for the replies Guys. That must be why I cannot find how to get in. I can see some foam type media behind the slotted intake so I guess one of the previous owners must have stuck so in by dropping the fan out. Guess i will try that.

Thanks again for taking the time.
Peter