My Pixma MP450 will not print, it just flashes

Hello, DH.

First and foremost, disconnect the power cord from the back of the Canon Pixma Printers. This is an important step when working inside ANY electronic device.

A 5100 error is a carriage jam error. That means something is jammed in the printer at some location. The error can be caused by 4 different sensors.

The Timing Strip (or encoder strip, plastic strip about 1/4" in width) that passes through the back of the carriage assembly can be contaminated with ink spots and this needs to be cleaned. Open the cover and use a flashlight to examine the strip. You really don't have much access to this strip unless you remove the cover, which can be difficult. But, clean with isopropyl alcohol and a Q-tip.

The other items that can cause this error are the sensor inside the carriage unit, the drive motor for the carriage arm, and the main logic card.

However, most of the time it is the timing strip which is easily contaminated with splattered ink.

If the problem persists, then use compressed air to blow the carriage assembly and the rollers.

Hope this helps.