Carolyn Hardy, I checked the service manual and do not see much in the way of adjustments. You can download it from [http://csparts.com.br/csprinter.com/Samung/CLP-600N.pdf|here] . Seems like there are a few other reasons that could do that. Check the sensor listed in the manual:
"1) Jam0 (Jam in feed area)
* After a page was picked up, it was not fed.
* Paper does not reach the feed sensor in a certain time.
* Feed sensor is faulty and does not detect paper.
- FCF pickup error: When a paper is not picked up in the 1st cassette.
- SCF pickup error: When a paper is not picked up in the 2nd cassette.
2) Jam1 (Jam inside printer)
* After the leading edge of the paper has reached the feed sensor, the feed sensor doesn't turn off (fails to detect the trailing edge
of the paper) in a certain time
* After the leading edge of the paper has passed the feed sensor, it doesn't reach the exit sensor in a certain time.
* Exit senor is faulty and does not detect paper.
3) Jam2 (Jam in exit area)
* After the leading edge of the paper has passed, the trailing edge of the paper has not passed the exit sensor within a certain time
* The paper drive motor has been driving for longer than the time needed for the longest paper size and the exit sensor is not off.
5) Jam MPF
* Paper could not be picked up from the MPF tray.
* After pickup, a paper has been fed, but it doesn't reach the feed sensor in a certain time.
* Feed sensor is faulty and does not detect paper.
The other option you have, is to check on this site http://www.fixyourownprinter.com Hope that this will at least get you started.