[2-in-1] Temp does not stop rising + rambo issue  

Re: [2-in-1] Temp does not stop rising + rambo issue

Hi Wig

I do rather think that the 2 issues are related.

Diode D6 is a Schottky diode (SK310A-TP) between the 12V rail and heater output. If it is S/C or wrong way around or even damaged, then I think the extruder heater will be on permanently.

You will need to get the problem resolved before you can go any further.

Peter

Re: [2-in-1] Temp does not stop rising + rambo issue

Hi PJR,

Thanks for the quick reply! Hum okay, this is not a good news. Do you think I should talk directly to UltiMachine or PrusaResearch ? (in order to test/debug or just get another one, those are not cheap board :/ )

Re: [2-in-1] Temp does not stop rising + rambo issue

Hi Wig,

Probably the best thing to do should be to contact Prusa support via the chat on shop.prusa3d.com. They definitely will help you.

Christophe

Re: [2-in-1] Temp does not stop rising + rambo issue

Just had another look at the circuit

You have an open circuit there at present, effectively Zero volts on pin D of the connector (top pin of the 4 in the picture). Pin C is held at 12V and when the heater is off, pin D is also at 12V.

The diode is the pull-up to turn the heater off.

Ideally, you would replace the board, but as you say, they are quite expensive (the downside of an all-in-one board). Personally, I would try to fix the board as at least you do know what the problem is...

Test the diode with a multimeter. Check it's right way round. Try replacing it (temporarily) with a 1N400x (although ideally, you need a similar Schottky - low drop/high speed).

Unplug the heater, power up the board and with the heater turned off check that there is 12V on both sides of the diode. Turn heater on, and one side (without the bar) should drop to 0V.

Peter

Re: [2-in-1] Temp does not stop rising + rambo issue

Christophe

I think it somewhat unfair to ask Prusa Support regarding this. OK, if a board was DOA. But when one of my glass clips jumped into the RAMBo box ans shorted the microprocessor, I just ordered another board. If it was repairable, I would have repaired it.

Unfortunately Wig is in a similar situation. An accident has happened that is outside the control of Prusa Research.

Peter

Re: [2-in-1] Temp does not stop rising + rambo issue

Hi Peter,

I didn't mean to ask support to replace the board, but asking them for assistance to troubleshot the issue and identify possible solutions. They do not have a result obligation here, but they can help by providing advices. I admit my advice was not very clear.

However, with what you described just there, it's probably not needed anymore.

Christophe

Re: [2-in-1] Temp does not stop rising + rambo issue

Hi Christophe

Thanks for that!

In all honesty, I don't believe that the PR support staff would be able to help much with this; it would be the tech staff that would have to get involved and they are very busy and any worthwhile response may take some time.

The information I have provided was taken from the schematics provided by Ultimachine, so should be pretty accurate. Wig's best option would be to contact Ultimachine directly.

Peter

Re: [2-in-1] Temp does not stop rising + rambo issue

Thank you to all of you.

@PJR, I was extra careful to solder it on the right orientation (max zoom on every pictures to be sure). I attached some pictures below, my phone has a really hard time focusing on the tiny component (it's in red :))

I cannot test further with my current equipment (no multimeter and no easy access to electronics for swapping the 1N400x). I'll contact UltiMachine to see if they can to something that does not involved replacing the whole board (I doubt it!). I guess my Prusa will just be more expensive than others 🙂

Thanks again, I will try to update this post and maybe it will help someone in the future.
Cheers.

Re: [2-in-1] Temp does not stop rising + rambo issue

Hi Wig

Yeah, it looks as though you have it oriented correctly. Unfortunately, there is no way to test it without some sort of meter.

There is a possibility that the tracks are also damaged, but again without a meter, you won't be able to test.

Even a cheap multimeter (£5) would be a good investment.

It is very sad that these things happen; as I mentioned, I had to replace the RAMBo - the rear left clip jumped off when I was releasin a part and shorted some of the microcontroller leads. Sh1t happens.

Peter

Re: [2-in-1] Temp does not stop rising + rambo issue

First of all, thank you very much for your help Peter & Christophe!

I finally managed to sort things out :D. After talking with Prusa, they told me that under normal circumstances this damage (D6 diode) wouldn't cause any issue with printing, as it is used to protect the board from overloading. So their advice was: double-check every connection.

They were right. I was so focus on thermistor, motors... that I forgot to check the PSU & heat bed / extruder. And I find out that I swapped those two. You heard me right, I swapped the PSU with the heat bed / extruder! The manual is clear on that part but my head was not.

So I fix the connections, replace the 5A fuse (motors) that die in the process, fix some endpoints / y-axis issues and everything is good now !

The only "issue" I have, is that I need to move the Z endpoint up, otherwise the nozzle is just diving into the glass like there is no tomorrow...
Calibrating is hard for a beginner! But the printer is printing, so at least the issue of this post is resolved :).

Proof:

Re: [2-in-1] Temp does not stop rising + rambo issue

Hey Wig, that's good news !

Prusa support rocks, even in circonstances when they are not responsible, they are anyway helpfull !

Regarding your issue with z position, you have several way to fix it.

First thing is to make sure the frame is not positioned too low. You can follow the procedure I described here to be sure that the Y-axis is perfectly flat and the frame will be properly positioned in the same time: http://shop.prusa3d.com/forum/prusa-i3-kit-building-calibrating-first-print-main-f6/prints-being-knocked-off-suddenly-t689-s10.html#p5388
You can modify the number of business card below each corener, I'm not well sure it's the best position, it just worked like this.

The other and simpler way to adjust minimum Z position is to move the Z-endstop holders a bit higher. You can use some business cards between the Z endstop and the Z-axis-bottom to ensure that both are in the same position. Quick tip to move them easily: insert a screwdriver in the Z-endstop slot and turn a bit (gently, do not damage it) to spread a bit the Z-endstop, it will be way easier to move it up and down.

I hope this will help.

Re: [2-in-1] Temp does not stop rising + rambo issue

Hi Wig

Yeah, I now remember that you are not the first person to have swapped the connectors.

Not sure about that diode being in place simply for protection though. It did seem to be there for a different purpose when I had a look at the schematic.

With regards to the Z axis. I do think that you have something built incorrectly. You should not have to fiddle with or raise the Z end stop. If the nozzle is too low, then either your bed it too high or your extruder is too low; nothing to do with the endstop. You need to get this sorted before proceeding, otherwise you could have more issues in the future.

Post some more pictures of the underside of the bed and the extruder so we can have a look.

Peter

Re: [2-in-1] Temp does not stop rising + rambo issue

@Peter @Christophe
I agree with you, there is probably something not right. I think the extruder is okay, it's almost too high (too close to the plastic).
For the bed part, I almost need to screw the nuts together to compensate the gap I need!
I will check the frame, I did touch it after my rambo issue, I'll let you know

I attached 3 pictures to give you some idea:

Re: [2-in-1] Temp does not stop rising + rambo issue

Hi Wig

Yeah, the extruder looks OK.

The third photo shows 3 things:

1. There appears to be a gap between nozzle and glass
2. You have a larger gap on the calibration nuts than I have
3. You have a larger gap between the bottom of the X axis and top of the Z end stop holder than I have - for me, there is almost no gap at that point.

Looking at that third picture, I think the gaps I see there which are not present on my printer would make up the difference on your Z end stop holder.

Peter

P.S. one more thought - the nuts holding the Y chassis to the frame; is the threaded rod as far down into the frame groove as possible?

Re: [2-in-1] Temp does not stop rising + rambo issue

Ok, after some verifications, the threaded rod was not completely down into the frame groove (only for one side).
So that's fixed my tweaking of the z end stop, it is now resting as far down as possible in its rod, that's a good news!

I think the y-axis could have move a little (for example, not a perfect rectangle anymore), because I can see all the calibration nuts not being at the same position (top right being way off the other).

I can still calibrate fine and this give me a relatively plane surface but this bother me a little.
When going back home, I'll maybe try to remove the little pad under the 4 feet to see if one of them is not properly touching the ground.
With the pad on and just a little pressure on each of them, nothing is wiggling... so we'll see!

Thanks again Christophe & Peter

Re: [2-in-1] Temp does not stop rising + rambo issue

Wig

One more thing - make sure that the Y threaded rods are as low as they can go in the Z frame grooves. You will need to slacken off the nuts a tad and lift the Z frame to do this. The result will be hat the Z frame has a good gap underneath it; the printer will only be supported at the 4 Y frame corners.

Peter

Re: [2-in-1] Temp does not stop rising + rambo issue

Wig

A final thought...

Make sure that both ends of the X axis are the same height above the Z end stop holders. Adjustment of this is very simple; just turn one Z threaded rod by hand (holding the other) until the X axis is level. Then re-calibrate the bed.

Peter