5S / „There is a problem with the active level sensor“

[PhantomGnom 2]

Hi Makers,

 

I have an unusable S5 since nearly 2 months. Right from the beginning, the printer returned a „There is a problem with the active level sensor“ during the leveling. Normally, I was able to solve it by turning it off and back on. Not very good, but solvable (Should not happen in this pricing segment). In the meantime, the error persists and I cannot solve it myself. When starting the job, he tries to level. The plate moves up to approximately half of the way, then stops with the mentioned error moving back downwards.

 

What I already did:

 

Installed the latest firmware

Factory reset

Switched Print core

Manual bed leveling 

 

I don’t know what to do...

[gr5 1,627]

There are a few things to check.  One thing you don't need to worry about is the firmware or rebooting.  That rebooting "fixed" your issue is probably a coincidence.

 

1) First and foremost, check the wires.  Swing open the print head and check the wires.  The sensor is a flat plate at the base of the print head (as close as possible and paraellel to the print bed when doing active leveling).  There are 2 wires there (for me it's a red and white wire).  Tug on each gently and if one is disconnected then this is the issue.  Also remove the 2 screws at the back of the print head (very long screws).  Don't worry - nothing will come loose if you only remove those 2.  At that point the print head rear top pops off.  Push down firmly on the connector that is now revealed to make sure it is seated (with the print head in a corner so you don't bend the rods).

 

2) keep electromagnetic energy away from your printer during auto level - make sure there is a 1 foot clearance around the printer during autolevel (e.g. no laptops within a foot of the printer).  Other S5 printers side by side are fine.  Most importantly keep your hands, head and fingers at least a foot away from the printer during auto leveling.

 

3) Since it sounds like your leveling failed before the nozzle touched the glass these last 2 things aren't related: Springs in the cores and bed can mess up autoleveling - you'll see the nozzle hit the glass and keep going - for a long long time (not just a half second but maybe 2 seconds).  If that happens then the springs in the core are too weak and/or the springs in the bed are too strong.  Loosen the bed springs by rotated CCW (from below) quite a bit or try different cores on the core that has the issue.  DON'T DO THIS if the autolevel fails before it touches the build plate.

 

4) Finally contact your reseller.  If they are not helping you, let us know here in the forum and let us know who your reseller is or at least what country you are in.  We can direct you to better support if your reseller isn't helpful.  Unfortunately for this issue they may want you to return the printer.  If your printer is less than a year old I'm pretty sure you can get this fixed for free.

[PhantomGnom 2]

Hi, I have checked the cables and plugged them out and back in again.

 

Here are some pictures...

 

No change... 😔

 

Link

[PhantomGnom 2]

Looks like, I have to contact my reseller Conrad Electronic in Germany.

[gr5 1,627]

Woah!  What the hell - it didn't even get close.  I'm wondering if your z steps go messed up somehow or it thinks you have a smaller printer (an S3?)

 

[PhantomGnom 2]

yes, very strange. I have really no clue...

[fbrc8-erin 241]

11 hours ago, gr5 said:

 

2) keep electromagnetic energy away from your printer during auto level - make sure there is a 1 foot clearance around the printer during autolevel (e.g. no laptops within a foot of the printer).  Other S5 printers side by side are fine.  Most importantly keep your hands, head and fingers at least a foot away from the printer during auto leveling.

 

A note on another cause of electromagnetic interference--if your front fan cable gets pinched it can cause interference that makes your active leveling fail.

 

Unplug the white and black fan cable and try running your active leveling again. If it works fine you need a new front fan.

[PhantomGnom 2]

Hi, you did it. That was the issue. They were not really pinched (black/white) , but they have moved to the mid close to the sensor plate crossing it at the edge. Moving them back to the left side as far as possible fixed the issue. Thank you so much...

[fbrc8-erin 241]

Glad it's back up and running again. 😀

[uncle_bob 20]

Hi

 

Just to add to the list of "electromagnetic sources": 

 

A cell phone is a big source. If you are talking on it, that's pretty obvious and you likely will work out what's going on. What's not quite so obvious is that they "wake up" every so often to chat with the base station. It's sitting there in your shirt pocket seemingly doing nothing. At the "wrong time" it's making every bit as much of a racket (but for a short period of time) as if you were having a conversation on it......

 

Not an issue on a "does it every time" sort of problem. It could be an answer to "why does it fail once a week / month / year?"

 

Bob

[jeffroe 3]

I know this is an older thread, but is it possible to elaborate on the way that this sensor works to help with troubleshooting?  One of our 6 printers is doing exactly this, and we checked the fan cables and other cables - all look OK.  There are no sources of interference nearby either.

 

The capacitive board appears to be electrically connected to the steel bottom plate (the "shield").  Is the steel plate supposed to contact the brass extruder body?  Or is there supposed to be a nominal gap there?  When the nozzle touches the bed, I am assuming that the brass moves away from the steel plate causing a change in capacitance?

 

It just seems odd that the process fails before the bed even gets up to the nozzle.  This would seem to indicate that the sensor reading is out of range for the "nominal" condition of the extruder (when no bed contact is occurring).

 

We did notice that the right-side hole of the sensor board looks a bit "off" compared to the other printers we have (sort of looks corroded - or "fuzzy").  I attached pics of the "problem" printer board and the "good" printer board.  It appears to me that there is an insulator wrapped around that mounting tab on the right side and the insulator has deteriorated or something.  (Someone else took these pics so I wasn't there to see them in person).

 

Thoughts?

[jeffroe 3]

Also, why is there only an insulator placed on that right-hand hole?

[Smithy 809]

 

8 minutes ago, jeffroe said:

Also, why is there only an insulator placed on that right-hand hole?

 

I've wondered the same thing, it's the same with mine and also with the S3. I think that is also not electrical insulation, that would not make sense.

 

Have you tried to raise or lower the bed a little bit, this often helps in such cases.

[jeffroe 3]

12 minutes ago, Smithy said:

 

 

I've wondered the same thing, it's the same with mine and also with the S3. I think that is also not electrical insulation, that would not make sense.

 

Have you tried to raise or lower the bed a little bit, this often helps in such cases.

I am heading to the office tomorrow to investigate further.  I don't think raising or lowering the bed will help here, since the bed only gets halfway up to the nozzle (from the bottom location) before the error comes up.  At least this is how it was described to me - so I will confirm tomorrow.

 

My assumption is that those bent tabs are an interference fit into the holes so there is electrical contact between the steel plate and the plating on the inside of the PCBA holes, and they are then bent over (and outward) to mechanically hold the plate in place.  I think the plate needs to be electrically connected to those holes for proper operation.  And whether that is an insulative part is confusing.  My thought is that maybe there is a vulnerable trace on the right edge of the board that they are making sure doesn't get shorted to the steel tab during manufacturing - but this is pure speculation.

[Torgeir 172]

Hi @jeffroe,

 

Did you really unplug the cooling fan and test? This is a must to do as the fan might create to much noise, even if the cables are located in the right place when fan is running..  This is something @fbrc8-erin learned us sometime ago.

 

When the leveling process start, the program read the "capacity plus stray capacity" in the head. As long this capacity is within specs, the bed start ricing. At certain height the program expect to see that the capacity is increasing, but if this is not happen, the bed go to home position the process is aborted and signal an error.

Also, the inside shielding of fan and lo part of housing is part of the active capacitor (shield side).

This little "heat shrink tube" might be a "rubber spring", -placed there to prevent the capacitor plate to vibrate and give false reading. (Just needed on one side.)

 

There is a weak point in the cabling (all moving cables has a lifetime) and this point is where the cables is bent when opening/closing the core/fan cooling door.

 

There can be an open wire, either the red or the withe but this will not be detected by the system cause it still can read a capacitance as the ruptured parts is close together (because here is an A/C present with a frequency that's measuring the capacity of the setup).

 

So, there might be a rupture inside the insulation that you cannot see.

 

 

Thanks

Torgeir

 

 

 

[jeffroe 3]

17 hours ago, Torgeir said:

Hi @jeffroe,

 

Did you really unplug the cooling fan and test? This is a must to do as the fan might create to much noise, even if the cables are located in the right place when fan is running..  This is something @fbrc8-erin learned us sometime ago.

 

When the leveling process start, the program read the "capacity plus stray capacity" in the head. As long this capacity is within specs, the bed start ricing. At certain height the program expect to see that the capacity is increasing, but if this is not happen, the bed go to home position the process is aborted and signal an error.

Also, the inside shielding of fan and lo part of housing is part of the active capacitor (shield side).

This little "heat shrink tube" might be a "rubber spring", -placed there to prevent the capacitor plate to vibrate and give false reading. (Just needed on one side.)

 

There is a weak point in the cabling (all moving cables has a lifetime) and this point is where the cables is bent when opening/closing the core/fan cooling door.

 

There can be an open wire, either the red or the withe but this will not be detected by the system cause it still can read a capacitance as the ruptured parts is close together (because here is an A/C present with a frequency that's measuring the capacity of the setup).

 

So, there might be a rupture inside the insulation that you cannot see.

 

 

Thanks

Torgeir

 

 

 

Yes fan disconnected at the back, and it still errors out.

 

I just reinstalled the silicone boot and tried with the fan plugged in again - still errors out.

 

Also checked continuity from the board terminals to the connector on the back of the extruder - those look fine.  Tugged on the wires at the board, they seem solid.

 

So basically stumped here.

[Torgeir 172]

Hmm. Strange this..

 

Both side of the cap sensor attachment holes is shield connected.

In the first posting, you've mention there there seems to be a sign of "corrosion".

The contact point of the red wire is isolated from the shield, and it is passed through the PCB connection to the "active" sensor foil on the underside of this circuit board.

The two picture of the sensor is made before and after cleaning and I guess the sensor was removed for this issue.

 

Maybe worth mention, cleaning captive sensors with water is a no, no thing in general.

However, since you mentioned corrosion, could water (due to high humidity "storing")been entering the PCB infill?

In general, -very rare, -but possible.

Water in one of the worst thing to fight in any capacitive measuring system.

 

As the nozzle is true ground and the shield is not -there should be no electrical contact between them.

When the metering procedure is ongoing, the slow speed approaching bed toward the nozzle will meet and the "capacitance increase" stop changing, -this is the signal to the software to stop moving the bed.

 

When measuring this sensor for open circuit and more than 100 M ohm resistance (reading OL - open line) is good.

From the red connector point to the underside "PCB" foil, we should red ~0 Ohm resistance..

That's pretty much all you can do, -before sending the printer to repair..

 

Last thing, or "sometime" first thing to do, -is to try "reset all printer setting" -will not erase the print cores data..

 

Maybe someone else have something to add..

 

Good luck

Thanks

Torgeir

[jeffroe 3]

38 minutes ago, Torgeir said:

Hmm. Strange this..

 

Both side of the cap sensor attachment holes is shield connected.

In the first posting, you've mention there there seems to be a sign of "corrosion".

The contact point of the red wire is isolated from the shield, and it is passed through the PCB connection to the "active" sensor foil on the underside of this circuit board.

The two picture of the sensor is made before and after cleaning and I guess the sensor was removed for this issue.

 

Maybe worth mention, cleaning captive sensors with water is a no, no thing in general.

However, since you mentioned corrosion, could water (due to high humidity "storing")been entering the PCB infill?

In general, -very rare, -but possible.

Water in one of the worst thing to fight in any capacitive measuring system.

 

As the nozzle is true ground and the shield is not -there should be no electrical contact between them.

When the metering procedure is ongoing, the slow speed approaching bed toward the nozzle will meet and the "capacitance increase" stop changing, -this is the signal to the software to stop moving the bed.

 

When measuring this sensor for open circuit and more than 100 M ohm resistance (reading OL - open line) is good.

From the red connector point to the underside "PCB" foil, we should red ~0 Ohm resistance..

That's pretty much all you can do, -before sending the printer to repair..

 

Last thing, or "sometime" first thing to do, -is to try "reset all printer setting" -will not erase the print cores data..

 

Maybe someone else have something to add..

 

Good luck

Thanks

Torgeir

 

I just got back from the office and read your response.  Thanks for that!

 

The two photos show 2 different printers.  The one with the "clean" RH tab holding the PCB in place is from the working printer.  The other photo shows the sensor board on the printer that keeps throwing the error, and has the RH holding tab showing what I previously described as corrosion (before having the opportunity to see it firsthand this morning). 

 

After seeing it this morning - I think it might just be that that "insulating" sleeve is deteriorated (almost looks like it is shredded).  I am attaching another picture of it.

 

I ended up removing the bottom plate assembly and bringing it home with me, along with another bottom plate/sensor board that we had from a print head disaster about 9 months ago.  That failure resulted in getting a new extruder head assembly, but we kept the old parts "just in case" we needed them.  This spare plate is not in great shape (bent) because the entire extruder filled with melted plastic.

 

I may attempt surgery on the two - or just try to fit new wires/connectors to the spare and bend it back into shape.  

[Torgeir 172]

This last picture makes me wonder, could this heat shrink tube be used as an insulator, in order to avoid any short short between the heat block (no 2 - the right) and the shield...

It might be the heat block that's made this damage to the shrink tube.

This ruin the measuring..   The right nozzle go far down in the housing and this must be the real reason for this tube/insulation damage...

 

Maybe a new lesson for us, -and sure me..

 

I'm curious to see if this is the cause of your problem..

 

Awaiting..

Torgeir

 

[fbrc8-erin 241]

The reason the heat shrink is there is to protect the heater cable for Print Core 2 so the metal tab doesn't damage it when the print core is moving up and down.

It's not needed on the other side because that Print Core is static and doesn't move up and down. 

 

Is your Print Core heater cable damaged by any chance? Have you tried swapping the Print Cores from your other machine in?

[jeffroe 3]

2 minutes ago, fbrc8-erin said:

The reason the heat shrink is there is to protect the heater cable for Print Core 2 so the metal tab doesn't damage it when the print core is moving up and down.

It's not needed on the other side because that Print Core is static and doesn't move up and down. 

 

Is your Print Core heater cable damaged by any chance? Have you tried swapping the Print Cores from your other machine in?

We did try different print cores and that didn't help (I know they swapped the left core - i am waiting for confirmation that they also swapped the right).  I will inspect those wires more closely next week.

 

22 minutes ago, Torgeir said:

This last picture makes me wonder, could this heat shrink tube be used as an insulator, in order to avoid any short short between the heat block (no 2 - the right) and the shield...

It might be the heat block that's made this damage to the shrink tube.

This ruin the measuring..   The right nozzle go far down in the housing and this must be the real reason for this tube/insulation damage...

 

Maybe a new lesson for us, -and sure me..

 

I'm curious to see if this is the cause of your problem..

 

Awaiting..

Torgeir

 

I will go back in next week (I am off work for a few days now) and inspect further to see if I can see if that was being rubbed/damaged by something in the head.  I didn't probe them myself, but someone else confirmed no continuity between the metal bottom plate and the nozzle.  I will double check this too while I am there.  

 

So the print bed moving toward the sensor is what the sensor is detecting?  I was guessing that it was detecting a change in capacitance as the RH print core touches the bed and the brass block moves upward and away from the steel plate in the head.

 

Thanks for the feedback!

[jeffroe 3]

Update:  ONLY the LH core was swapped - not the right.  So I guess that is something else I need to try next week!

 

Thanks again

[jeffroe 3]

Update to my issues:

 

I replaced the heatshrink on the RH tab that was deteriorated and reinstalled the bottom cover with no change in the leveling test.

 

I then tried pushing the heater wires up to make sure they weren't in contact with the tab.  No change.

 

I then replaced the RH print core with a different one.  There was a noticeable mark on one of the wires (see pic).  Still no change.

 

Removed both print cores and tried to do the leveling sensor diagnostic.  Test wouldn't complete so I backed out.

 

Factory reset printer.  This DID change something.  It would at least go through the entire process of the test, and then popped an error about low performance of the sensor.  I made sure that the wires were separated well (front fan and sensor wires), and confirmed that the wires were all intact and not loose.  Still the same low performance error.

 

Tried running the XY calibration and it errors out saying that it couldn't complete.  Note this is  different error than i was getting before the factory reset.  The older error would be a white screen with black text that you can't exit from without power cycling the printer.  The new error can be exited out of and I can get back to the menus.

 

We have a new bottom cover/sensor assembly on order.  Hoping that fixes it, but I just don't know.

 

Note that the picture attached shows the print core that was in the printer initially in the RH location on the right of this photo.  The one I put in its place is shown on the left.  You can see a dark spot on the print core heater wire (or is it the temp sensor wire?) in the photo.

[Torgeir 172]

Hi @jeffroe,

 

Good catch.

It looks like it is burned, -should not be as the place it is touching is "cold"..

If you look more closely, could there be a hole in the insulation?

This is the heater, and if this is the +24 VDC this can make some heat.

So if 24 VDC enter this "ground" that's alternating at a frequency, the capacitive sensor might be destroyed.

This one is actually installed inside the print head, the mall PCB where the fan and the capacitive sensor connectors are installed.

Again check this little brown spot and if you see the wires in there, -you know whats failed..

 

Thanks

Torgeir

[jeffroe 3]

25 minutes ago, Torgeir said:

Hi @jeffroe,

 

Good catch.

It looks like it is burned, -should not be as the place it is touching is "cold"..

If you look more closely, could there be a hole in the insulation?

This is the heater, and if this is the +24 VDC this can make some heat.

So if 24 VDC enter this "ground" that's alternating at a frequency, the capacitive sensor might be destroyed.

This one is actually installed inside the print head, the mall PCB where the fan and the capacitive sensor connectors are installed.

Again check this little brown spot and if you see the wires in there, -you know whats failed..

 

Thanks

Torgeir

I will take a closer look next time i am in office.  I wondered the same - it could be a hole in the insulation or at least a place where it frayed (since the heatshrink on the tab was in bad shape I think this is a good possibility.  Here are a few more pics I took this afternoon along with a pic I think I posted before of the tab on that side of the sensor board.  I put new heatshrink on that tab now.