Dell 1210s

Hello everyone!

I have searched online and through the knowledge base as well as the forum before posting so please forgive me if this is out there and I missed it. I have a customer that has deployed projectors for their classrooms. Its been several years since their initial implementation so keep in mind that these projectors are at least 2-3 years old.

One of these projects has black dots on the display. It doesn't look like pixelation but rather something is on the display. I've attempted to blow off and clean the outside of the lens but they are still there. Is there a way to clean out the projector? I have worked with other models that allow me to get inside and clean them out but not sure how to do it on this model.

I also have another projector that after 10 mins of use it begins to get lines on both sides of the display. It juststarted recently on this projector but in the past this happened to a projector and theyjust replaced it. I've read that the frequency needs to be adjusted but I didn't know how to accomplish this as most of the menu is grayed out.

Thank you!