Door switch on the SR 5060 and SR 5050 finishers can be a source of problems. We had one that we got in Monday the 23rd, main frame had come in the week before. It was delivered Wednesday. After 17K pages, it started giving SC 670-80 and SC 670-82 codes at powered on coupled with J 121, 123 and 125 as well as a couple of other SC codes in the SMC report. We called tech support and were told to check the door switch and harness, apparently some harnesses are being installed with no slack and that have been reports of switch failures. The harness was OK so I decided to try shimming the switch. Eight thicknesses of 20# paper under the tab on the door that actuates the switch allowed the machine to come to ready, but got a J100 as soon as the stapler cycled, causing enough vibration to cause the switch to open momentarily. J100 is a finisher door switch open. It took four additional layers of paper to stop the J100. In the past I have had to shim Pro 8110 finishers due to J100.