The 1300 has a high failure rate of the fuser. When the fuser burns out, you can have that problem. It is easily replaceable. You can find a number of resellers with a Google search. If your laserjet has made around 5,000 copies that will be the case. It also has a power supply that can be replaced. Schematics are available at HP.
A common symptom before failure is the toner powder fails to stick to the paper. Look at recent copies to see if you can rub the toner ink off with your hand.
An electrician with a multimeter can tell if it is a power adapter. There are laser repair tech shops in nearly every major city. But you only need to be skilled with a screw driver to replace the parts. Cost about $80. You can remove the power unit yourself and test it or take it to be tested.
If you have made that many copies, all those things need to be replaced anyway.

thanks

If you knew how to use a multi-meter and knew what to look for you wouldn't be posting this, and because you don't I would be doing you a disservice instructing you to open the case and start playing around with line voltages.

If the unit has as many hours as you imply it may not be worth investing anymore time or money, a qualified tech is going to cost you anywhere from $60. per hour and up. If this is a business you should be able to write off the purchase of a new machine on your taxes.