Probe stays lit

Need help troubleshooting hardware issues... talk here

Probe stays lit

Postby AgentTDM » 2018-Jan-Thu-01-Jan

Had the new sensor that I used as a replacement working for a while...Only to wake up to find the new one with its light staying on as well even after it finished printing. My fear was confirmed when I saw it was no longer stopping/leveling like normal when I went to start a new print...Second probe that this has happened to. I have no idea what to do now, especially since even running new wiring and installing a new probe only made the problem go away for a while.
  • 0

AgentTDM
Loading filament...
 
Posts: 17
Joined: 2017-Oct-Thu-23-Oct
Reputation: 0

Probe stays lit

Sponsor

Sponsor
 

Re: Probe stays lit

Postby RetireeJay » 2018-Jan-Thu-08-Jan

That does seem odd.
The probe senses nearby metal. Ideally, it would only sense metal "on-axis, in front" of the probe, but there's probably some sensitivity to metal that's off-axis but close to the front of the probe. So I'd suggest imagining that the probe is sitting on top of a slightly squishy ping-pong ball, and figure that any metal inside that ping-pong ball could trigger it. It will be more sensitive to steel than aluminum, but any metal can trigger it.
  • 0

Printrbot Plus operational January 2013
Brass threaded rods (5/16" X 18) & nuts for Z axis
GT2 belts & pulleys
Cable chain to reduce probability of fatigue failure in wires
E3D V5 Hot End, 0.4mm nozzle, also 0.8 and 0.25 in use occasionally
PB fan mount + 40mm fan -- using printed mount adapter, not the E3D supplied fan
Injection molded extruder gears
Optical Z "endstop" (custom designed and built)
Have used many pounds of T-Glase filament. Now also doing some work with Ninjaflex SemiFlex
Print on glass with Scotch Craft Stick or other glue stick
"My next printer is..." Prusa i3 MK3
User avatar
RetireeJay
My next printer is...
 
Posts: 4936
Joined: 2013-Jan-Wed-13-Jan
Location: Greenville, SC
Reputation: 495

Re: Probe stays lit

Postby AgentTDM » 2018-Jan-Thu-08-Jan

The probe still does it even if I take it off of the mount and keep it away from metal. So, I'm not sure what the deal is. The red light is dim as well. I wonder if the z-stop section on the Printrboard is just starting to fail.
  • 0

AgentTDM
Loading filament...
 
Posts: 17
Joined: 2017-Oct-Thu-23-Oct
Reputation: 0

Re: Probe stays lit

Postby RetireeJay » 2018-Jan-Thu-10-Jan

If you have the ability to temporarily jumper power to the probe (pins 2 & 3) but leave the "sense" lead (pin 1) disconnected, you could isolate the output signal of the probe from the input circuit on the board. Then you'd know for sure: if the probe stays "triggered" when connected only to power, then the probe is bad. If connecting the probe's output signal to the board is what forces it to appear "triggered" then there's a problem on the board.
Printrboard Rev F Endstops.PNG
  • 0

You do not have the required permissions to view the files attached to this post.
Printrbot Plus operational January 2013
Brass threaded rods (5/16" X 18) & nuts for Z axis
GT2 belts & pulleys
Cable chain to reduce probability of fatigue failure in wires
E3D V5 Hot End, 0.4mm nozzle, also 0.8 and 0.25 in use occasionally
PB fan mount + 40mm fan -- using printed mount adapter, not the E3D supplied fan
Injection molded extruder gears
Optical Z "endstop" (custom designed and built)
Have used many pounds of T-Glase filament. Now also doing some work with Ninjaflex SemiFlex
Print on glass with Scotch Craft Stick or other glue stick
"My next printer is..." Prusa i3 MK3
User avatar
RetireeJay
My next printer is...
 
Posts: 4936
Joined: 2013-Jan-Wed-13-Jan
Location: Greenville, SC
Reputation: 495

Re: Probe stays lit

Postby AgentTDM » 2018-Jan-Thu-11-Jan

After doing an M119 command on the terminal, I saw that "z_min" was saying triggered when nothing is connected to the z-stop. Other times it would say "open when I connected something to it. I used a regular endstop to test that. I could only get it change from open to triggered a few times before it stopped.
  • 0

AgentTDM
Loading filament...
 
Posts: 17
Joined: 2017-Oct-Thu-23-Oct
Reputation: 0

Re: Probe stays lit

Postby RetireeJay » 2018-Jan-Thu-11-Jan

AgentTDM wrote: "z_min" was saying triggered when nothing is connected to the z-stop

That's the correct behavior. If there's no electrical continuity between pin 1 and 3, then the board interprets that as "triggered". If there's a short between pin 1 and 3 (like an "endstop" switch that's not being touched) then M119 will report that as "open". Technically, it's actually an electrical closed circuit, but the switch is in the "open" or un-touched position.
  • 0

Printrbot Plus operational January 2013
Brass threaded rods (5/16" X 18) & nuts for Z axis
GT2 belts & pulleys
Cable chain to reduce probability of fatigue failure in wires
E3D V5 Hot End, 0.4mm nozzle, also 0.8 and 0.25 in use occasionally
PB fan mount + 40mm fan -- using printed mount adapter, not the E3D supplied fan
Injection molded extruder gears
Optical Z "endstop" (custom designed and built)
Have used many pounds of T-Glase filament. Now also doing some work with Ninjaflex SemiFlex
Print on glass with Scotch Craft Stick or other glue stick
"My next printer is..." Prusa i3 MK3
User avatar
RetireeJay
My next printer is...
 
Posts: 4936
Joined: 2013-Jan-Wed-13-Jan
Location: Greenville, SC
Reputation: 495

Re: Probe stays lit

Postby Mooselake » 2018-Jan-Thu-12-Jan

It's a safety feature. CNC home and limit switches are predominantly "normally closed" so a broken wire is interpreted as a trigger and you'll fix the problem. Not as important in a lightweight 3D printer where a full throttle crash might pinch your finger a little, but extremely important if you're slinging a couple tons around and a crash could mean continued employment for a paramedic, plus a spare parts and billable time bonanza for the repair tech.

Printrbots, like virtually all 3D printers, only check these switches when homing. A missing or broken switch won't affect normal operation, just finding home (or the dreaded alien probing) when asked to do so with the appropriate gcode

Kirk
  • 0

Modified KickStarter Classic Plus 7/2012
KS Thingybot Delta Pro 10/31/16
User avatar
Mooselake
My next printer is...
 
Posts: 3587
Joined: 2011-Dec-Tue-23-Dec
Location: Moose Swamp, Upper Michigan, USA
Reputation: 172

Re: Probe stays lit

Postby AgentTDM » 2018-Jan-Thu-14-Jan

RetireeJay wrote:
AgentTDM wrote: "z_min" was saying triggered when nothing is connected to the z-stop

That's the correct behavior. If there's no electrical continuity between pin 1 and 3, then the board interprets that as "triggered". If there's a short between pin 1 and 3 (like an "endstop" switch that's not being touched) then M119 will report that as "open". Technically, it's actually an electrical closed circuit, but the switch is in the "open" or un-touched position.

I
If there is a short in those pins, can the z-stop connector on the board be replaced?
  • 0

AgentTDM
Loading filament...
 
Posts: 17
Joined: 2017-Oct-Thu-23-Oct
Reputation: 0

Re: Probe stays lit

Postby AgentTDM » 2018-Jan-Thu-14-Jan

I wonder also if this type of sensor contributed to the problem as well. It says 6v on its lowest side..And someone was telling me later on that the Printrbot only puts out 5v on that z-stop. Is that right? https://www.amazon.com/gp/product/B075F ... UTF8&psc=1
  • 0

AgentTDM
Loading filament...
 
Posts: 17
Joined: 2017-Oct-Thu-23-Oct
Reputation: 0

Re: Probe stays lit

Postby RetireeJay » 2018-Jan-Thu-16-Jan

We need to know exactly which version of Printrboard you are using. There are slight differences from version to version regarding how they feed power to the probe and how they receive the signal from the probe.

That said, the probability of a failure of the connector itself is nearly zero. My reference to a short circuit or open circuit between the outer pins was in terms of experimentation you could do for troubleshooting.

Depending on the exact model of Printrboard, there are different possible scenarios regarding the transistor on the board that receives the sense signal, and the wiring that sends power to the probe. For example, in the schematic I showed earlier, you can provide the probe with a choice of either 12V or 5V for its power supply.
  • 0

Printrbot Plus operational January 2013
Brass threaded rods (5/16" X 18) & nuts for Z axis
GT2 belts & pulleys
Cable chain to reduce probability of fatigue failure in wires
E3D V5 Hot End, 0.4mm nozzle, also 0.8 and 0.25 in use occasionally
PB fan mount + 40mm fan -- using printed mount adapter, not the E3D supplied fan
Injection molded extruder gears
Optical Z "endstop" (custom designed and built)
Have used many pounds of T-Glase filament. Now also doing some work with Ninjaflex SemiFlex
Print on glass with Scotch Craft Stick or other glue stick
"My next printer is..." Prusa i3 MK3
User avatar
RetireeJay
My next printer is...
 
Posts: 4936
Joined: 2013-Jan-Wed-13-Jan
Location: Greenville, SC
Reputation: 495

Re: Probe stays lit

Postby AgentTDM » 2018-Jan-Thu-22-Jan

RetireeJay wrote:We need to know exactly which version of Printrboard you are using. There are slight differences from version to version regarding how they feed power to the probe and how they receive the signal from the probe.

That said, the probability of a failure of the connector itself is nearly zero. My reference to a short circuit or open circuit between the outer pins was in terms of experimentation you could do for troubleshooting.

Depending on the exact model of Printrboard, there are different possible scenarios regarding the transistor on the board that receives the sense signal, and the wiring that sends power to the probe. For example, in the schematic I showed earlier, you can provide the probe with a choice of either 12V or 5V for its power supply.


The one I'm using for the Simple Metal is the Printrboard Rev F4.
  • 0

AgentTDM
Loading filament...
 
Posts: 17
Joined: 2017-Oct-Thu-23-Oct
Reputation: 0

Re: Probe stays lit

Postby RetireeJay » 2018-Jan-Fri-08-Jan

The schematic that I showed a few posts earlier is correct for the Rev F4. You have a jumper on the board that selects whether to power the probe with either 5V or 12V. If your probe is indeed one that can be powered from 6 to 36V, then your power selection jumper should be on the 12V (or HV) side.

At some point in the production of Rev F boards, they changed from using an FET (as is shown in the schematic) to using a bipolar transistor with built-in biasing resistors. That's because the FET is more fragile than the bipolar variety. There was no change in the layout of the board; each transistor fits in the exact same space. I say all this to say that it's possible for the FET to "burn out" without any visible damage. BUT if your board actually has an FET instead of the bipolar transistor, and IF the FET is burned out, then you would NEVER see any change of state using the M119 command, no matter what you did to the sense lead coming from the probe (or switch).

Not knowing the schematic of the probe, I can't say whether a burned-out FET could cause the probe's LED to come on continuously.

IF the problem is the FET, I can dig through my files and find the part number for the bipolar transistor. It would only cost you a couple of dollars to get from DigiKey. Then a shop that repairs cell phones should be able to replace the transistor on your board. Total cost would be much less than buying a new board.

But if you do decide to get a new board, don't get a Rev G unless you want a big adventure; they are totally different. Any of the Rev F boards would be physically and firmware compatible with what you have now.
  • 0

Printrbot Plus operational January 2013
Brass threaded rods (5/16" X 18) & nuts for Z axis
GT2 belts & pulleys
Cable chain to reduce probability of fatigue failure in wires
E3D V5 Hot End, 0.4mm nozzle, also 0.8 and 0.25 in use occasionally
PB fan mount + 40mm fan -- using printed mount adapter, not the E3D supplied fan
Injection molded extruder gears
Optical Z "endstop" (custom designed and built)
Have used many pounds of T-Glase filament. Now also doing some work with Ninjaflex SemiFlex
Print on glass with Scotch Craft Stick or other glue stick
"My next printer is..." Prusa i3 MK3
User avatar
RetireeJay
My next printer is...
 
Posts: 4936
Joined: 2013-Jan-Wed-13-Jan
Location: Greenville, SC
Reputation: 495

Re: Probe stays lit

Postby AgentTDM » 2018-Jan-Tue-13-Jan

RetireeJay wrote:The schematic that I showed a few posts earlier is correct for the Rev F4. You have a jumper on the board that selects whether to power the probe with either 5V or 12V. If your probe is indeed one that can be powered from 6 to 36V, then your power selection jumper should be on the 12V (or HV) side.

At some point in the production of Rev F boards, they changed from using an FET (as is shown in the schematic) to using a bipolar transistor with built-in biasing resistors. That's because the FET is more fragile than the bipolar variety. There was no change in the layout of the board; each transistor fits in the exact same space. I say all this to say that it's possible for the FET to "burn out" without any visible damage. BUT if your board actually has an FET instead of the bipolar transistor, and IF the FET is burned out, then you would NEVER see any change of state using the M119 command, no matter what you did to the sense lead coming from the probe (or switch).

Not knowing the schematic of the probe, I can't say whether a burned-out FET could cause the probe's LED to come on continuously.

IF the problem is the FET, I can dig through my files and find the part number for the bipolar transistor. It would only cost you a couple of dollars to get from DigiKey. Then a shop that repairs cell phones should be able to replace the transistor on your board. Total cost would be much less than buying a new board.

But if you do decide to get a new board, don't get a Rev G unless you want a big adventure; they are totally different. Any of the Rev F boards would be physically and firmware compatible with what you have now.

The jumper is set to the "HV" side of the board. So, it may have just been that the sensor that I purchased as a replacement was faulty and just went out on its own. I have another sensor coming in a few days. So, I'll try that first, before doing anything else.
  • 0

AgentTDM
Loading filament...
 
Posts: 17
Joined: 2017-Oct-Thu-23-Oct
Reputation: 0

Re: Probe stays lit

Postby AgentTDM » 2018-Jan-Wed-05-Jan

Just tried the new probe and wiring now. It's still not doing anything with the sensor problem. Even when I use the old wiring or new, nothing happens. There's not even a light showing anything is active in the sensor now. I'm afraid that that section on the board has just gone bad. Time to switch over to one of my spare RAMPS or other boards. That Printrboard in there right now is just showing that it can't do the job anymore.
  • 0

AgentTDM
Loading filament...
 
Posts: 17
Joined: 2017-Oct-Thu-23-Oct
Reputation: 0


Return to Troubleshooting talk

Who is online

Users browsing this forum: No registered users and 1 guest