The first test you should do will ensure that paper is loaded and power is wired up correctly and the printer is running.

First up, pull the little plastic tab up top to open up the paper holder. Then insert a roll of 58 millimeter (2 1/4 inch) thermal paper into the bay as shown in the image below.

To reiterate from the first page, the printer models and corresponding roll sizes are:

• Mini: 15m / 50 foot roll
• Tiny: 10m / 33'
• Nano: 5m / 15'
• Guts: no paper bay; use any size roll

Make sure that the paper doesn't bind or stick in the bay, it should rotate freely.

As described on prior page, power the printer using a 5V to 9V 2A or higher power supply, such as wiring up a 2.1mm DC power jack:

Print Test Page

Most of these thermal printers have a test feature providing basic diagnostics. You’ll then know that power is good, paper is correctly loaded, and have some configuration details of the particular unit.

On most Mini and Tiny printers: hold down the button on the top of the printer while connecting power to print a test page. In normal use, tapping this button feeds the paper by one line.

On most Nano printers and printer guts: connect power first, then tap the button on the control board to print a test page.

Not all “printer guts” units have a button installed. If needed, you can make a temporary connection across the “J1” pads using a jumper wire or metal tweezers.

Occasional factory production changes occur…if you don’t get a test page using the method above for you model, try the opposite method. A few may even lack a test page feature, but the status LED provides an indication of good power.

If you don't get a printout, check that the paper is inserted correctly and not binding, that the power is correctly wired, power supply is plugged in, etc. Then try again.

Note the baud rate on the test page. This may be 19200 or 9600. We'll need this number later: