3300 Project Card Read Problems

I have several 3300 projectors and use the card reader module w/ Sandisks for presentations. We worked out the naming issue to get the slides to show up in order, but are  having problems at a greater and greater rate. Is anyone else having problems? Is there a known issue with the card reader?

 

Randomly, our presenters take out the machines, plug in the card and then the WAIT screen comes up. This on a machine where it worked before taking it out. We have reformatted the disks, reloaded the slides, changed the order of turning the machine on and inserting the card.

 

Last year, we didn't seem to have so many of these issues. Are the disks bad? (They work fine in a computer) Help!

 

It's extremely embarrassing and frustrating to not be able to trust the equipment to work as it should.

 

Any ideas?