First of all thank you for posting your question here at Fixya.
You've mentioned that you can hear a slight grinding noise. This noise came from either a faulty color wheel or fans. To isolate where the fault came from, first I would advice you to access the "error code operational check". This is a built-in software that log and give an equivalent error code by means of blinking LED to determine the exact caused of the symptoms.
How to access the "Error Code Operational Check".
1. Turn on the TV and wait until it automatically shutsdown.
2. Pressing the front panel "Input" and "Menu" buttons at the same time, and holding for 5 seconds, activates the Error Code Mode. The Timer LED flashses denoting a two digit Error Code.Example, if the error code is "42" the led will flash 4 times pause and flash 2 times and it will cycle for a total of 5 times.
Please let me know what is the error code.
If you can't access the error code mode because the TV didn't gone to shutdown. I would advice you to open the rear panel of the TV to pinpoint where the grinding noise came from.
1. Remove 8 screws (A) from the external input frame.
2. Remove 10 screws (B) form the rear cover.
3. Pull the rear cover from the TV.
Tape the lamp cover switch to closed position like on the picture above or else the unit will not turn on.
Your TV has a 3 fans :
1. DMD fan
2. Lamp fan
3. chassis fan
If the grinding noise came from the fan(s) you have to replaced it. All fans have the same part no. 299P312010
However if the noise came from the optical engine assembly, you have to replaced it part no.938P059050