X-motor don't work properly

K8200 3D Printer K8200 - Assembly and user manual
1

I’ve ordered a new X-motor, took me some weeks to get it, and when switching with old X-motor, old problem is still there. My conclusion will have to be that it’s not the motor…

So, the problem is that the X-motor don’t run smoothly, or at all. My Z and Y motors feels and sounds fluid, X-motor sounds and fells grumpy.

Moving it manually is ok. It goes fairly fluid from side to side. Moving it with Repetier host 0.84 doesn’t work att all. It protests, and refuses to go anywhere.

Any clue?

2

I found this posting, that describes the same problem. It’s without the solution though.

viewtopic.php?f=48&t=9994&start=15

3

Hi TomWen,

just to be sure, I’d recommend to check the resistances of the motor coils in case there’s a short somewhere. With the connector unplugged, the pins should measure as follows:

  • pins 1 & 2 and 3 & 4: 2.0 to 2.5 Ω
  • all other combinations: high resistance / no connection

You can also compare with one of the working motors, of course.

If the measurement is ok, test the motor driver boards (Pololus):

  • doublecheck the reference voltage, is it between 0.425 and 0.550 V? A low voltage setting would result in low current and torque, a high voltage setting in thermal shutdown of the driver.
  • Switch two motor connectors and try to move the X axis with e.g. the Y controls (caution: endstop will not work). This way, you can make sure that the motor is ok and moving without blockage when driven by one of the outputs known to be working.
  • Last but not least, switch two Pololus and try to move the X axis with the other motor driver mounted on the X socket, and also try to move the other axis with the motor driver that was on X previously.

Cheers,
kuraasu

4

[quote=“kuraasu”]Hi TomWen,

just to be sure, I’d recommend to check the resistances of the motor coils in case there’s a short somewhere. With the connector unplugged, the pins should measure as follows:

  • pins 1 & 2 and 3 & 4: 2.0 to 2.5 Ω
  • all other combinations: high resistance / no connection

You can also compare with one of the working motors, of course.

If the measurement is ok, test the motor driver boards (Pololus):

  • doublecheck the reference voltage, is it between 0.425 and 0.550 V? A low voltage setting would result in low current and torque, a high voltage setting in thermal shutdown of the driver.
  • Switch two motor connectors and try to move the X axis with e.g. the Y controls (caution: endstop will not work). This way, you can make sure that the motor is ok and moving without blockage when driven by one of the outputs known to be working.
  • Last but not least, switch two Pololus and try to move the X axis with the other motor driver mounted on the X socket, and also try to move the other axis with the motor driver that was on X previously.

Cheers,
kuraasu[/quote]

Thanks. Switching X-motor and Y-motor connections moves the problem to Y.

5

[quote=“TomWen”][quote=“kuraasu”]Hi TomWen,

[b]just to be sure, I’d recommend to check the resistances of the motor coils in case there’s a short somewhere. With the connector unplugged, the pins should measure as follows:

  • pins 1 & 2 and 3 & 4: 2.0 to 2.5 Ω
  • all other combinations: high resistance / no connection[/b]

You can also compare with one of the working motors, of course.

If the measurement is ok, test the motor driver boards (Pololus):

  • doublecheck the reference voltage, is it between 0.425 and 0.550 V? A low voltage setting would result in low current and torque, a high voltage setting in thermal shutdown of the driver.
  • Switch two motor connectors and try to move the X axis with e.g. the Y controls (caution: endstop will not work). This way, you can make sure that the motor is ok and moving without blockage when driven by one of the outputs known to be working.
  • Last but not least, switch two Pololus and try to move the X axis with the other motor driver mounted on the X socket, and also try to move the other axis with the motor driver that was on X previously.

Cheers,
kuraasu[/quote]

Thanks. Switching X-motor and Y-motor connections moves the problem to Y.[/quote]

How do I measure this? I’m a bit off when it comes to multimeters, settings and voltage.

6

Hi TomWen,

your multimeter should have (among others) two modes of operation: resistance and continuity. Resistance is in most cases indicated with the Ω unit symbol, continuity with a diode symbol and/or a “sound” symbol (because of the beeping).

To measure the pins in the connector, you’ll need test leads with a fine tip. With those, it should be possible to contact the small hooks in the sideways opening in the connector housing. Alternatively, you can of course use alligator clips and two pieces of wire (from a paper clip or similar) to assure good contact with the pins in the connector.

In this case (resistance and conductivity), the polarity of the measuring leads doesn’t matter. Pin 1 is marked on the connector, but from the electrical point of view, it’s symmetrical: one coil is connected through pins 1 and 2, the other coil through pins 3 and 4.

Start with the continuity check and test all possible combinations of two pins. Only two combinations (the coils) should “beep”, all others must remain silent, and the multimeter display should read overrange (usually “1___”). If this measurement looks good, switch the multimeter to resistance mode, autorange (if present) or lowest Ω range, 200 Ω or 2 kΩ perhap. Measure the resistance of pins 1 and 2, and after that, pins 3 and 4. The resistance should be the same for both coils, and in the range previously given.

Cheers,
kuraasu

7

[quote=“kuraasu”]Hi TomWen,

your multimeter should have (among others) two modes of operation: resistance and continuity. Resistance is in most cases indicated with the Ω unit symbol, continuity with a diode symbol and/or a “sound” symbol (because of the beeping).

To measure the pins in the connector, you’ll need test leads with a fine tip. With those, it should be possible to contact the small hooks in the sideways opening in the connector housing. Alternatively, you can of course use alligator clips and two pieces of wire (from a paper clip or similar) to assure good contact with the pins in the connector.

In this case (resistance and conductivity), the polarity of the measuring leads doesn’t matter. Pin 1 is marked on the connector, but from the electrical point of view, it’s symmetrical: one coil is connected through pins 1 and 2, the other coil through pins 3 and 4.

Start with the continuity check and test all possible combinations of two pins. Only two combinations (the coils) should “beep”, all others must remain silent, and the multimeter display should read overrange (usually “1___”). If this measurement looks good, switch the multimeter to resistance mode, autorange (if present) or lowest Ω range, 200 Ω or 2 kΩ perhap. Measure the resistance of pins 1 and 2, and after that, pins 3 and 4. The resistance should be the same for both coils, and in the range previously given.

Cheers,
kuraasu[/quote]

I don’t get any reaction at all, anywhere.

8

[quote=“TomWen”][quote=“kuraasu”]Hi TomWen,

your multimeter should have (among others) two modes of operation: resistance and continuity. Resistance is in most cases indicated with the Ω unit symbol, continuity with a diode symbol and/or a “sound” symbol (because of the beeping).

To measure the pins in the connector, you’ll need test leads with a fine tip. With those, it should be possible to contact the small hooks in the sideways opening in the connector housing. Alternatively, you can of course use alligator clips and two pieces of wire (from a paper clip or similar) to assure good contact with the pins in the connector.

In this case (resistance and conductivity), the polarity of the measuring leads doesn’t matter. Pin 1 is marked on the connector, but from the electrical point of view, it’s symmetrical: one coil is connected through pins 1 and 2, the other coil through pins 3 and 4.

Start with the continuity check and test all possible combinations of two pins. Only two combinations (the coils) should “beep”, all others must remain silent, and the multimeter display should read overrange (usually “1___”). If this measurement looks good, switch the multimeter to resistance mode, autorange (if present) or lowest Ω range, 200 Ω or 2 kΩ perhap. Measure the resistance of pins 1 and 2, and after that, pins 3 and 4. The resistance should be the same for both coils, and in the range previously given.

Cheers,
kuraasu[/quote]

I don’t get any reaction at all, anywhere.[/quote]

Should I use the black or red multimeter stick for measuring or is it that I should put them simoulaniously? I suppose the pins are the x-motor pins on the circuit board? Is it enough to touch them with the multimeter stick edge?

My multimeter is a UNI-T Clas Olsson Edition UT132E clasohlson.com/se/Multimeter … 2E/36-5256

9

Hi TomWen,

you should use both leads, and measure at the unplugged connector like this (different connector, but you’ll get the picture):

The tip will push on a small hook that holds the connector in its housing, so don’t use too much force there. If you’re not sure whether you get good contact with the tips like shown above, use small wires instead.

Make sure that the leads are plugged into the COM and Ω ports of the multimeter.

Cheers,
kuraasu

10

[quote=“kuraasu”]Hi TomWen,

you should use both leads, and measure at the unplugged connector like this (different connector, but you’ll get the picture):

The tip will push on a small hook that holds the connector in its housing, so don’t use too much force there. If you’re not sure whether you get good contact with the tips like shown above, use small wires instead.

Make sure that the leads are plugged into the COM and Ω ports of the multimeter.

Cheers,
kuraasu[/quote]

Ok, done.

Result (measured with 200Ω) on X-motor connection:
Pin 1 and 2, 1.6
Pin 3 and 4, 1.6

All other combinations are quiet.

also tested Y-motor connection:

Pin 1 and 2, 2,2
Pin 3 and 4, 2,2

Z-motor

Pin 1 and 2, 2,3
Pin 3 and 4, 2,3

Hmmm, seems that that was done in recistance mode… and it beeps in the beep mode…

So, 1.6 on X versus 2.2 on Y and Z?

11

I really don’t want to replace the circuit board, it’s fairly expensive. Any advice?

12

Hi TomWen,

what about the third test? It should be useful in order to determine what’s at fault here:

The resistances of both the Y and Z motors seem to be ok. For the X motor it’s a bit low, as you also noted. That’s the replacement motor, right? Do you still have the “old” motor for comparison?

Anyways, the test with the Pololus switched over should tell you whether it is just the motor driver board or the controller board which is to blame here.

When did you buy the printer?

Cheers,
kuraasu

13

[quote=“kuraasu”]Hi TomWen,

what about the third test? It should be useful in order to determine what’s at fault here:

The resistances of both the Y and Z motors seem to be ok. For the X motor it’s a bit low, as you also noted. That’s the replacement motor, right? Do you still have the “old” motor for comparison?

Anyways, the test with the Pololus switched over should tell you whether it is just the motor driver board or the controller board which is to blame here.

When did you buy the printer?

February/Mars, from Elfa Sweden. This was the replacement motor, and the problem was there with the original. I’ve had ridicilous problems with getting the spare parts and then this problem, it’s kind of getting really annoying. Would really like to start printing.
Cheers,
kuraasu[/quote]

14

How do I switch the two Polulus? You will have to provide a photo on that. I’m a software and business guy, not an electronics engineer.

Measured drivers:
e 439
z 451
y 451
x 450

15

Just switch place on 2 of the driver boards you measured on. Keep track of the orientation though so you don’t burn them.

16

Thanks! Didn’t realize that they were unsoldered.

The result is that X-motor now works wonderfully, spins like a cat. Y-motor who got the X-motor driver inherited the problem, and that problem is not as big in this configuration - but it’s there.

Time to buy a new driver. Project is 14 weeks behind schedule… Buying a new motor in Swedn/Norway was a ridiculous project, it took 10 weeks to fail that in Norway.

17

No drivers to buy in the Swedish market. In theory www.kjell.com or ELFA should have the stuff, in reality they don’t. My new goal to build this i now scheduled to christmas.

18

We can offer inspection/exchange.
Please return assumed defective driver to:

Velleman Projects Tech. Dept.
Legen Heirweg 33
9890 Gavere
Belgium

19

Hi TomWen,

Reichelt seems to be out of stock, too. However, Conrad(.se) could be worth a look, from what I can see.

Maybe also helpful: there’s a Swedish user group in the RepRap forum. The wiki also lists a few shops from Sweden, but they seem to be focused on selling filament for the most part.

Cheers,
kuraasu

20

Conrad delivered a new driver card, did cost a bit. It did solve the problem though. I lost 10-12 weeks, root cause - the faulty driver card, main problem lack of spare parts on the market in combination with delivery problems in Norway.