Selftest failure  

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paul.p7
(@paul-p7)
Active Member

Hey 🙂

I managed to get my upgrade assembled and upgraded the firmware, so all was fine up until then. When the self test runs, the first step with the extruder fan fails, and gives me a "Selftest error ! Please check : Left hotend fan? wiring error" message. So I checked, and rechecked and re-rechecked it, but it's wired as in the assembly documentation and can't be plugged in in the wrong direction from what I can tell, and still can't get through the first step of the self test (which then worries me that this is the tip of the iceberg ;))

The fan is switched on and turning when I power the printer on, if that makes any difference. I am really at a loss about what to do next, so any suggestions would be appreciated

 

Thanks

Paul

This topic was modified 6 months ago by paul.p7
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Posted : 28/01/2020 8:18 am
BillCampbell
(@billcampbell)
Reputable Member

The left end fan should NOT run as soon as the printer is turned on, so sounds like there is something wrong with the wiring.

It should only run during the short calibration test and when the hotend temperature exceeds 50 degrees C.

Compare your positioning of the Rambo connector with the photo from the electronics section of the online assembly manual. If it is right you need to find a short circuit in your wiring.

 

Bill
Tagaytay City, Philippines
Founder member of Philippines Prusa Printer Owners FB Group
Sponsor Pillars of God Academy in Bacoor...
Posted : 31/01/2020 10:08 am
paul.p7 liked
paul.p7
(@paul-p7)
Active Member

Thanks Bill, I did skip the self test and went to settings to see the RPM of the fans, and even though it was spinning, it was reading as 0 .... so then I am guessing something somewhere is miswired. I unplugged everything and replugged it and the exact same thing happens. This time with a MIN HEATBED error ... so I dunno where to start the trouble shooting - am even tempted to do the 4 hour drive to Prague and wait outside Prusa's offices to see if theres someone there who can help me 😀 

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Posted : 31/01/2020 11:19 am
BillCampbell
(@billcampbell)
Reputable Member

You may be able to find someone a little closer than that. Use the World Map here on prusaprinters to  find someone offering tech support in your area.

Bill
Tagaytay City, Philippines
Founder member of Philippines Prusa Printer Owners FB Group
Sponsor Pillars of God Academy in Bacoor...
Posted : 31/01/2020 1:19 pm
paul.p7 liked
wayne.w3
(@wayne-w3)
New Member

I just finished by MK2S to MK2.5S upgrade and am in exactly the same situation. I did all the assembly, upgraded the firmware to 3.9.0 which seemed to go fine. I went next to this self test. But the left fan comes on instantly when I power up the printer--just like the prior report--and the self test fails on the first step with the same message as reported above.

But there is no resolution to this problem posted?

Other things I have done:
1. The printer being upgraded is 2 years old and was in good condition (so I am pretty confident of all the other parts).
2. I have built this MK2S and, later, an MK3 and then MK3S upgrade--that is, I have gone through the build of several printers several times successfully.
3. I looked very carefully at the left fan v cable. All looks in order. If I power up unplugged at the Rambo, the fan doesn't come on, but the self test fails on the first step that way, too. I discovered that only the single-cable black connector need be unplugged at the Rambo to prevent the fan turning at power up.

4. All 3, xyz axis can be manually moved.

5. the heat bed and nozzle will heat up manually and properly read out their temperatures.

6. After heating the bed from Settings...I retried self test and it first went to "cooling down" and successfully turned on the other fan. The left fan, as is the problem, runs all the time regardless.

I haven't tried heating the extruder or moving its motor or loading filament. Need to figure out this fan problem first.

I have removed the Rambo from its case, but with all its cables still plugged in so I can see  all the connectors, and top and bottom of the Rambo PCB. I see nothing of note.

Any hints?
Wayne

Posted : 02/07/2020 2:40 pm
wayne.w3
(@wayne-w3)
New Member

Well, as soon as I admit publicly I am an idiot and go through the instructions one more time, I see my mistake. I had installed the reverse of the color coding on the Extruder Cable bundle: PINDA and left hot end fan. Self test is fine after cabling as instructed.

 

Posted : 02/07/2020 3:28 pm
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