Omnitech 10 sheet shredder keeps running constantly after a page or pages have been completely shredded. I have to stop it and start it manually.

Unplug it, open it up and clear the jam, reassemble and give it a try, and try not to shred too many pages at once and make sure that you empty the lower part so it doesn't pick up already shredded material and jam up again.

Sounds like its jammed? Have a really close look for staples, paperclips etc stuck in the drive gears or blades

Drive mech

Drive mech depending on type it may either be a drive belt or adjustment of mech

This may be of help, this is a bit outside my experience:

Tale of the Dead Staples Omnitech Shredder Why Not Fix it Yourself

Good luck-

You must first unplug it and look inside the shredding blades, especially around the spot usually near the center, where there is a pressure button. When paper hits it, it starts shredding. Chances are some pieces of paper have jammed just over it stopping paper from hitting it and switching it on. I have had to use long tweezers to work the jammed bits out... Once clear it will work again. Also using shredder oil every 50 sheets through will help it cut easier , and jam less frequently. Do not put too many sheets through together in a bunch. No staples...

Sounds like a bad or stuck sensor, acting as if it is always seeing a peice of paper in it. Check if you can find it and maybe it is just stuck to the on position..

I don't have that model but have an 8 page cheapo shredder. It takes CDs, credit cards and staples with no whining.

Did you ever put shredder oil onto the cutting blades?????
The blades can clog with paper dust and then it can't shred as many papges as it should or even jam completely...you should occasionally shred a sheet of paper with shredder oil poured onto the sheet.