How to identify hardware components?

Hello everybody,

I'm new to this forum and - after a lot of googleing around - hope to find some help in here...
I bought a cheap china Prusa i3 a couple of months ago on ebay and have already printed a lot of objects with it that came out quite nice.

Now I'm facing a couple of problems that I'd like to solve, but I just can't seem to find the right answers by searching around the web.

My main problem is, that I can't identify the components used in my printer. It seems like they're all no-name china clones of popular 3D printer components.
For example the board looks like a Geeetech 2560 board but it is missing the GT Logo (that's why I think it's a clone).
The stepper motors look like Nema 17 Motors but I have absolutely no idea how to find out, what model they've been copied off.
The stepper drivers have printed HR4988 on them, so I think they might be pololu A4988 clones.
The firmware is Marlin (says Repetier Host - I don't know the version number).
The extruder looks similar to an MK8 extruder, though it doesn't have the "clamp" thing that the MK8 extruder has.

For solving the main problems I'm facing, I think I need to determine, what components the printer is made of. Is there a way to find out?

Thanks in advance!

The steppers are not labelled? Maybe we can reverse engineer what they should be like, by reading the Vref of the stepper drivers. Identify the shunt resitors on the driver PCB and recalculate the current they are running ATM. Are they getting too hot? Do they skip steps? Does the driver get too hot? If so, then you know how to adjust that.

When you connect your printer to Pronterface ( or Repetier? ), you'll see a screen dump of the most relevant settings. Make a screenshot of it, in case you want to update the controller to a newer firmware ( from scratch )

Hey thanks for your reply!

I actually took the extruder motor off the carriage and found out it does have an imprint.
It is labeled as RB Step Motor 17HDC4023-24B, so I am now pretty sure it is a Nema 17 clone (with hopefully the same technical parameters).
I'm just going to assume that the other clone parts have similar technical parameters to the original ones.

One of my main problems at the moment is the very very noisy X-axis. I've tried everything already... changing the motor current up and down, taking the whole X-Axis apart completely, putting lubricant on the guide rods, checking the linear bearings, ...
It seems that the belt is causing vibration as soon as it is tightened. I'm currently operating the printer with a VERY loose belt on the X-Axis to avoid vibration, which is not the best idea, I guess.

Another problem is that my prints have wrong sizes. Holes are too small and outlines lines come out too big. I tried printing the supernova lamp from thingiverse (http://www.thingiverse.com/thing:810091) and none of the parts fit :-(
I've already read a lot about holes being too small on prusa printers but I just don't really know where to start. I'm currently trying different settings and slicers, though I can't seem to get any nice prints with slic3r at all (cura is working pretty good).

Nema 17 is a physical motor size only. The electrical characteristics are normally made to order by the manufacturer as is the shaft dimensions. The fact that it works off a 4988 chip means its fairly standard for reprap type specs

I bought a prusa I3 clone about 6 months ago, i allso had a noisy X axis which turned out to be the pololu driver chip (yes i measured the v ref voltage).
after fitting a replacement driver pcb (maybe this is why they supply spares) my printer is now hardly audible while printing,
the extruder fan is actually the noisier part now.

It seems 'holes' are allways a bit of a problem due to shrinkage of the different types of plastic used.

If it's not the driver chip being noisy, you might have non matching pulleys and belts ( GT2 belt on a MXT pulley or vice versa? ) or the idler bearing has a ball with a flat spot.

NEMA 17 is not a brand name, but a specification standard.

Hey everybody, thank you so much for your replies.

I thought NEMA 17 was a brand name... oops. I was actually trying to calculate the optimal motor current for my motor, but to do that, I need to know the maximum current the motor can take. How do I find out?

@Obewan: what do you mean by fitting a replacment driver pcb? Did you just buy a new stepper driver and got rid of the old one? I actually don't think the noise is coming from the driver. I took the whole X-axis apart and had the stepper motor run without a belt connected to it and it was very quiet. Then I connected the belt without the linear bearings and had it running - it was still very quiet. it seems when I connect the belt with the extruder carriage / linear bearings, there's some kind of vibration. The linear bearings and the extruder carriage run smoothly on the guide rods, tho (I moved them by hand with and without the extruder carriage). And the vibration doesn't occur, when the belt is very loose, it just starts vibrating when I tighten the belt :-( Could it be the motor itself? Then again - to exchange the motor, I need to know what motor to buy...

@o_lampe: the printer has a "S2M" belt on it and as far as I know, that's pretty similar to a GT2 belt. I have already changed the pulleys from the original (plastic) ones to GT2 metal pulleys. It doesn't make any difference at all. I now ordered a GT2 belt and will try to exchange the belt to find out if that fixes the noise. I'm going insane over that noise :-D!

Oh and concerning the size problem... is ABS filament more reliable than PLA filament when it comes to correct sizes? The parts on my printer that were printed by the manufacturer seem to have perfect sizes. When I print the exact same objects, they're not the correct size (holes too small, outsides too big). I'm guessing, the manufacturer is using a prusa i3 printer to manufacture the printed parts, too so why do they come out the correct size on his printer and not on mine? There must be a way to fix this...

Edited 1 time(s). Last edit at 12/30/2016 04:41AM by mitzy.

Swap the X and Y motor plugs and the X Y end stop plugs then see if the X carriage(now controlled by Y movement) is still noisy.

I know this is a really old post but I purchased what I assume is the same Prusa i3 clone off eBay and was having the same problem with the juddering x axis. I believe I may have solved the problem after having a play about with it tonight. The driver chips you mentioned had the Vref set as 0.8 volts and I believe this is way too low. After adjusting it to 1.6 volts the motion seems much smoother. I too was having problems with the scaling of my parts and solved this by changing the steps/mm in the firmware, however I haven’t managed to permanently change the values, they reset to default every time I switch it off. Hope this can be some use to somebody, I’m quite happy with my first 3D printer and intend to better it over the coming year now I have the bug