Strange sound from PC when shutting off

I recently bought a PC 7424XP and used it for the first time yesterday, getting some practice on my '04 Honda Pilot. I installed 4" backing plate w/spacer and polished the hood using PO203S with a LC white 4" pad. As I was finishing the last few work areas, I noticed that when I was shutting the PC off, there was a grinding/screeching kind of sound the last couple seconds as the head stopped rotating. The PC wasn't making this not-too-good sounding noise when I first started polishing. It almost sounded as if the motor was binding up a little, since when I would use my finger to manually spin the counterweight it seemed a little sticky & then would free up and rotate more freely. I can't think that I did any damage to the PC since I only used it for maybe 20 minutes but it sure doesn't sound right.

Any thoughts or similar experiences?

 

I think that is some sort of a braking mechanism to stop it from rotating quickly..I've had woodworking tools with the same concept for added safety..I have the 7424XP and mine makes the same exact noise that you are talking about.

Sean,,,,,,,,,

 

Thanks Sean, that puts my mind at ease. I ddidn't hear that sound the first several areas that I polished, and everything came out ok, but I was freaking out a bit when I started hearing this!

 

My old 7424 did the same thing. I sent it in for warranty and it came back noise free. Not sure what caused it.

 

Before I snapped the thing in half, it used to move freely for quite a while before stopping. After the shaft got repaired, it was never the same. I suspect that I have to oil the bearings or something...