Printrbot 140507 diagnostic help

[barto]

Hello - I got a used Printrbot from a local maker space that was closing down. I got it for free with the caveat that its condition is unknown(there is a beginning of a print on the bed so seems to have been functional). I got an 850 watt ATX power supply for it, when I turn it own however it doesn't seem to work. I can see the green light on the Printrbots board but my computer won't detect it over USB. Micro SD doesn't seem to work either. Theres also a 4 pin molex connector that I'm not sure what to do with too.

Looking for any ideas on how I could diagnose the issue or any advice in general. Im not finding too much information on this model since it is a few years old. Ive been wanting a 3D printer for years and am lucky to be gifted this so I really want to make it work. Thanks!

[__Vinz__]

Hi there,

Based on the number, this looks like an old version of the Plus, as in http://printrbot.com/wp-content/uploads ... -front.png. Is that right?

Diagnostic-wise, I would start by pursuing the USB connection problem. You might want to disconnect everything from the Printrboard, except for USB and power supply and check your connection from there. Are you using Windows or Linux as your host computer?

If you could post pictures, I think this would help people identify it too.

[barto]

that looks like the one. Im using windows. i tried it on my macbook too and was getting the same results. the light on the Z sensor also lights up briefly when i turn on the power and again when i power it off. the board is a Rev F4

[RetireeJay]

The two Molex connectors on the back panel are clearly wired in parallel - meaning you could use either the 2X2 connector or the 4X1 connector for providing power to the unit.
One weak spot in the Printrboards below F6 was the USB connector. The "micro" connector was subject to partial breakage: it would still be physically attached to the board, but one or more of the individual circuits would have broken away from the board. This can be hard to diagnose. Sometimes you can apply some pressure in just the right direction on the connector so that the broken parts make electrical contact and it works. That's not a repair, but merely a diagnostic test to see if the problem is in the connection. If you decide that the problem is a broken USB connection, you may be able to find someone locally that can fix it. Shops that repair cellphones deal with broken USB connectors all the time.

[novice]

What happens if you try to export a sliced Gcode file to the SD card, rename it auto0.g, insert it into and then power up the printer, does it heat up and eventually start to print? IIRC, one of my 3 Windows OS would not recognize the Simple Metal F4 board before doing a serial driver install routine, have you done it?

[barto]

signs of life! so i unplugged everything from the board and plugged back in, also tried a new usb cable. my computer detected it! i tried to run a small test print with no filiment to see if it works. the build bed moved all the way to one side and started vibrating really hard so i powered it off. i assume i should probably calibrate it first but that gave me a little worry. when i try the home command in Cura, its going way too far on the Y axis and thats when it locks up.

thank you all so much for the insights so far!

[RetireeJay]

Exactly what were you doing when the bed moved all the way to the end and started vibrating? Were you giving commands to increase Y, or did you give it a "home" command?

When you turn the power on, the printer defaults to thinking that its current location is 0, 0, 0; this is generally not true. So before you move any axis under manual control or try to start a print, you need to first tell the printer to go "home". This causes it to move in the X, Y, and Z directions until it reaches microswitches or triggers the Z sensor. Once the switches & sensor have been triggered, the printer "knows" where it is.

If, when you give a home command, the printer reaches the end of an axis and starts vibrating then one of two things has happened. Either (a) your sensing switch or circuit is not working (which could be a mechanical or an electrical problem) or (b) your firmware is not matched to your printer, and the printer is looking for "home" in the wrong direction so it never finds the switch.

[barto]

i clicked the home button and it went +Y and then started binding up. i can move it in small increments but im unable to actually center the build platform with the extruder. i also raised the Z axis but now it wont go back down. really confusing. it definitely seems like it doesnt know where home is

does the same thing if i try to start a print. X axis seems to be fine, Y axis is off

[RetireeJay]

Printrbot created two different versions in regard to homing on the Y axis. One version homes to Y = 0; the other version homes to Y = MAX. See viewtopic.php?f=16&t=3484 for a pictorial describing where 0, 0, 0 is.

My favorite User Interface program is Repetier. They do ask for a donation, but you can download it for free if you want; if you don't plan on using it long-term I would say there is no guilt in using it free for testing.

So, with Repetier as the interface, here's how to figure out where the problem is.

First, you need to find the mechanical switch that gets activated by end of motion on the Y axis. It may be activated by Y reaching 0 or may be activated by Y reaching MAX, so you have to look around.
Next, have the power on and Repetier (or another UI that shows you "home" icons and also current X, Y, Z positions) connected to the printer - and also have your finger ready to push the Y axis "home" switch.
Next, click the Y "home" icon on Repetier and then, anytime you like before the Y axis hits a limit, you manually press the home switch. This SHOULD cause the motion to stop. If it does not cause the motion to stop, then you have a problem either with the switch itself or with the wiring from the switch to the board.
Finally, assuming that the motion did stop when you pressed the switch, look at what Repetier is telling you is the Y position. Is it zero, or is it max? This is where the firmware thinks Y "home" is.

At this point, you have three possibilities:
- If the Y axis was moving in the correct direction, toward either zero or max, and the switch should have been activated, then look for a mechanical issue that's preventing the switch from getting activated when the Y axis reaches that point.
- If the Y axis was moving in the correct direction (toward zero or toward max), but the switch is at the wrong end of the axis, then you need to get a different version of the firmware installed that looks for "home" where the switch really is. You need to have physical "home" match firmware "home".
- If the Y axis was moving in the wrong direction, then you can unplug the cable from the Y axis motor, turn it end for end, and plug it back into the Printrboard; this will reverse the direction of the motor. However, this won't fix the problem if the firmware doesn't agree with the actual location of the switch.

It's normal for the firmware to prevent you from going to negative values. It will move in the "negative" direction only when doing a homing maneuver.

Your printer has a Z "probe" to detect the metal bed. When you give a command for Z to go home, it should move down toward the bed and stop (after "bouncing" a bit) with the nozzle just a fraction of a millimeter above the bed.

[barto]

found the switch - but its not getting triggered by the build bed when it moves. out of curiosity i tried to do a test print to see what happens. it seems like the X and Y axis are working ok, they went to the center where i would expect the print to start. however the print started with the Z axis/extruder all the way up! then when the Z axis tried to move now that was making sounds and was stuck in place. i assume theres also some method for leveling the bed too that i need to do. also the fan isnt working. so many things to figure out! Yaxis.jpg

[barto]

heres a vid of it in "action". X and Y seem to be fine