For example, if all LEDs turn on, holding the Go key down might turn off all of the LEDs except for the Attention LED.
![hp laserjet 1100 hp laserjet 1100](https://manualmachine.com/html/bf/bf58/bf58778261c1239974c7ac7ad801fadd1eee6a7d67155d781a033561beb69a18/htmlconvd-1Udo5h1x1.jpg)
This pattern can be used to identify what type of fatal error it was. Some LEDs might be on and some might be off, but it will be a non-changing pattern as long as the Go key is held down. During this mode, pressing and holding the Go key down will reveal a pattern on the LEDs. All LEDs will turn on or, in the case of an Accessory Error, all LEDs will start flashing. The printer may encounter a severe error, one that inhibits further operation. In the following anything in italics is my addition. The winding down noise is the laser/scanner spinning to a stop. Please, help me to solve the problem, if someone has any idea what to do. It drives me a little crazy, because it does not appear to be a true "fatal error", when from time to time the printer behaves correctly! I've made a phonecall to a HP service and they've told me, that could be a heater or fuser error, and fixing the problem would cost almost that much I've bought the printer for! It doesn't help every time, I'd say - almost never. Once it appeared it worked, on other times - no. I've read the posts above, make some probes with the cover switch. Once after such a experiment after pressing the button while the 3 leds were on, the led in the middle was flashing, the rest was dark. The printer becomes again unresponsive, and randomly after few minutes, hours or days, when powered on and off and on, it becomes ready again and prints correctly some pages. Sometimes the last page has a dark stripe in the middle across after the incomplete page. However, once for some time after powering the printer on it goes ready and prints normally! It prints 4 to 60 pages, as deserved, and then while printing it makes a descending noise, like some airplanes do, and stops printing, it doesn't intake paper and the 3 leds flash again constantly, after pressing the button flashes only the led of the button. After powering the printer off and on again there were similar results (leds, "ticks"). No control printout after pressing the button, the computer says, the printer is not responding. After pressing the button only the led belonging to button flashed, the 2 other leds became dark. I've made maybe 100 prints and one day the printer just didn't start printing like normally, but make no normal start noise, but some 2 quiet "ticks", and the three leds started to flash constantly.
![hp laserjet 1100 hp laserjet 1100](https://i.ytimg.com/vi/CHzBSij95ZY/sddefault.jpg)
I have much similar problem as described in previous posts: I've bought a LaserJet 1100, it should be almost new and it really looks new. My money is on the tab broken or missing. If that is not the case with your printer, then you have a laser/scanner error and you will want to check the cables (usaually not the cause) and the next step would be to replace the laser/scanner. If it does, you will have to replace the cover or as I have done on occasion, super glued a small piece of plastic fashioned to the size of the tab. About the only way to test this if the tab is broken is to unplug the printer, put a piece of cardboard or some other material to push in the switch, close the door and apply power and see if the printer comes to ready. I have seen this tab break off or be bent to one side so the swtich is not activated when the door is closed. If you open the toner door, on the frame near the top a little to the right of center is a switch which is activated by a plastic tab on the toner door when it is closed. One thing i have seen on may occasions with this error is a tab broken on the toner door. It can be as simple as the plastic tab which activates the laser/scanner switch breaking off. Post it here and someone will tell you what is wrong. If all the lights come on and stay solid without blinking then you have a fatal error and pressing the big button will give you a secondary light pattern. The only way to correct this problem is with crazy glue. I seen cases where the plastic posts which hold the main board in the front of the machine break causing all sorts of problems. If it does not print, you have other problems.
![hp laserjet 1100 hp laserjet 1100](https://images-na.ssl-images-amazon.com/images/I/71RySvTGLrL._SS400_.jpg)
If it prints, the formatter is the problem. Press the button and see if you get a page to print with vertical lines. Lift up the memory door in the back and a little to the right will be an engine test button. Real easy just remove the screws, lift up by the side and disconnect the connectors which go to the board. Remove the formatter from the botton of the machine. It could be the formatter, but also be the main board or the way the main board is secured to the frame.