Summary

A test pattern for debugging printrbot problems. May be useful to others.
The green example is PLA sliced to 0.1mm.
The red is ABS sliced to 0.2mm.

Instructions

There are several .stl files. The testtextonly.stl just has text on a 1mm base. The test.stl is much larger and has extra shapes. In particular people are having trouble with Y axis motion and the zigzags test this.
Slic3r often screws up the zigzags - you can see this if you preview the g-code. Don't panic if they don't print.

For people having trouble getting the first layer to stick - round shapes are easier. So I've added X.stl - a circular base with an X as another simple pattern.

100and50sqr-b.stl is what I use to calibrate X and Y steps.

holetest.stl is just some differents sized holes.

Rodtest is a test shape for checking printrbot rods are perpendicular. In particular people using their printers to print new printer parts should check everything is squared up. This is true for making other parts as well. The part has a 8mm tube to take a 8mm rod as used in the small PB.
The idea is to measure the rod angle against the flat bottom.
The cross shape can also be used to check X and Y are at 90 deg.

Test123456 is something I did to test my cooling fan. Each number is 1mm higher than the one before so there is less and less time for the layers to cool. If you can print this your cooling is pretty good - but maybe too good?

Ribtest (aka z-wobble).
This might get its own page later because it is a big subject.

My test shape is a cylinder/tube.
Ribbing due to variable Z lift shows up most on thick walls and solids.
It also shows up more when using solid fill.
It typically shows up on .2mm or less slices but can show up on .4 if it is bad enough.
But there is more.
It is worse if you are over-extruding.
For plastic bots the ambient and motor temperature also matter because the motor mounts are softer when hot.

This pattern also makes a good test for over-extrusion.

The pattern is solid at the bottom - this shows up over extrusion and ribbing.

Ribbing caused by Z lift will extend in all directions. Ribbing due to actual XY wobble won't do that.

There is then a section with a hole in the centre.

Z lift ribbing will also show up in the hole and the ribs will be the same "phase" as the ribs on the outside. IE it will bulge inwards at the same time as they bulge outwards.

The top section is a 1mm walled tube.
I would expect ribbing to be much less in this section but I can't test it because my printer doesn't make ribs any more.

Print this pattern solid at not more than .2mm slices.

I also mention the ribbing issue here - http://www.youtube.com/watch?v=Fu6An4-wFZQ

The test prints in the image are .2mm for the bottom two and .1mm for the top one.
For the bottom right one I tried to make it wobble by loosening my mounting screws but it refused to do it.
All my other mods may have somethng to do with that.

test pattern.