Lights will not stop flashing on the screen

When it tells you to check the fan it mans the device is overheating.
you can try buying a air spray and spraying it into the device/use a vacuum cleaner on the fan ports in case there is dust blocking the system

The manual is no help but I would think it's trying to tell you there's a short sensed on one of the rear speaker cables. Disconnect them both and see how that works out, then diagnose.

If the message doesn't reset the base unit is sick. take it to someone to look at it.

http://www.retrevo.com/support/Samsung-HT-Z510T-Home-Theater-Systems-manual/id/14714ci454/t/2/

I had the very same problem, and found that if you power up the receiver in DVD/CD mode, or tap the function button to display DVD/CB mode, the Wireless Rear Speaker AMP will automatically recognize and turn on the sound. This work around was not posted anywhere in the manual, just 1 of many workarounds I have had to put up with this system to work. Right now my fan went and it just keeps shutting down, I have had this system for about 15 months and very disappointed with the quality. My DVD player stopped working a few months ago, so now the system is rendered useless, not even sure it is worth fixing at this point since it is no longer under warrenty.

It is just that main unit is looking for the "Wireless sub-woofer" and shows this message when it can't find the sub.
wireless connection between main unit and sub should be reset.

Got that exact same problem and do not know what to do. Help !!

Did u ever find a solution? The room I use the home theater in gets quite hot. I use an air conditioner but I think prolonged use in the heat has ruined the fan(s). The speakers will power up, and sound can be heard but after a minute or two the CHK FAN will come across the display, and ultimately, shut the system off. Is this what happens to you? T?hanks for any and all responses!,
Ed

With the home theater system off, press the 0-1-3-5 buttons in that order on the home theater's remote control.

Power on the home theater system.

With the wireless module on, press the [ID SET] button on the back of the wireless module for five seconds.

If your home theater continues to display rear check after you have tried the steps above, call Samsung Customer Care at 1-800-SAMSUNG (1-800-726-7864). Have your model number and serial number on hand to set up service.

Hope this helps!

it means the home theater is over heating and the unit will shut down to prevent any damage. This can happen if the unit is stacked along with other electronic devices or the unit is in an enclosed area that prevents the unit from cooling properly. To decrease the chance of overheating, relocate your home theater to a more open area.

If the home theater display reads PROTECTION every time you turn it on, no matter where or how the unit is placed, it needs service. To set up service call Samsung Customer Care at 1-800-SAMSUNG (1-800-726-7864). Have your model number and serial number on hand to set up service.

Wireless speakers are not turned on or they may be placed out side of range.

Looks like it is to do with the rear wireless speaker. Now, my problem is over. Its gone. I first turned the reciever on and then turned on the rear speaker wirel less on. No rear chk in problem now. Hope this helps. R.