My ML-3561 clicks on & off when I turn it on - Samsung ML-3561N Laser Printer

Common issue with Samsung Laser Printers. Your power supply is failing or in your case has basically failed. There are a series of capacitors on the power supply that go bad from heat and begin to fail. When this happens the machine usually begins "rebooting" after a print job, turns on and off randomly and eventually will not power on at all. Good news is it is a fairly simple repair. The power supply must be removed and the bad capacitors replaced. Parts are less than $25.00. Labor I would charge would be around $75.00 so a total of around $100. The trouble is going to be finding someone locally that can or will do the job. You can try checking your local yellow pages for printer repair places and see if they can help you.