Warranty Void if Removed

On monday evening I connected up the various parts of the printer and managed to get it to print for the first time since it was dismantled.

The printer is bristling with sensors to check that the various hatches are installed, the cartridge is in, paper isn't jammed, and so on. They all have to be fooled correctly to get it to print.

The door microswitch was taped open. A wadge of card was stuck in the paper sense photointerruptor to make it think the tray was full. The paper drawer photointerruptor was left open, which means "paper tray closed".

Here's a photo of the setup

 With the help of my housemates we 

• Turned on the printer with a bit of plastic wedged in the leading edge photointerruptor
• Waited for initialisation (green Ready light) and pressed the Go button to initiate a test page
• The main motor and laser motor then spin up. Rob held the paper load solenoid to feel for the paper load event
• About 2 seconds after the solenoid pulse, the leading edge photointerruptor was cleared. This signals to the laser head to start lasering
• About a second afterthat, a piece of paper was fed into the rollers.

 The paper came out with a beautiful, crisp test page image. The fusing stage wasn't performed, so the toner could very easily be smudged all over the place.

 These steps were repeated to print onto 1.6mm stripboard. We had no bare copper clad board, and it seemed a waste to strip a bit of presensitised board. Again, a beautifully crisp image was produced.

 Finally we fed the board through the fuser unit by hand to test for toner adhesion. With a very slow feed rate it looked promising, but the printer timed out before we had time to feed the whole board through. The printing cycle could not be easily restarted with the board inside the fuser as the fuser unit contains a paper jam sensor. 

I measured the voltage across the fuser for a full printing cycle and it remained  at 230Vac throughout.  So I decided to take a risk and connect the fuser straight to the mains. A sacrificial kettle lead and a bit of chocolate block later (with plenty of gaffer tape for safety) the fuser was ready for direct operation.

Slower manual feeding produced better adhesion, but the joy was short lived - the heating element gave up. I foolishly neglected to measure the element resistance before this insane experiment, but it now measured open circuit, which can't be right. So either the element has smoked, or some kind of thermal fuse has blown.

Time for a new fuser, some kind of temperature monitoring / control, and some copper-clad board.