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New Kit won't Run thru Self Test  

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Sam
 Sam
(@sam-14)
Active Member
New Kit won't Run thru Self Test

I have built a new MK3 and cannot get it to get past the Self Test . I get an error for the heater/thermistor is not connected. We have been online with Prusa support and have tried everything including replace thermistor, heater cartridge and einsy board. It will not send power to the hotend or bed even if we bypass the Self Test and go to the temperture page.

Napsal : 10/04/2018 6:29 pm
digibluh
(@digibluh)
Reputable Member
Re: New Kit won't Run thru Self Test

if you replace all that and it still don't work, it can't be anything but User error.... or one of the PSU power plugs.... Multimeter helps. everyone should own one anyway.

Napsal : 10/04/2018 6:35 pm
Sam
 Sam
(@sam-14)
Active Member
Topic starter answered:
Re: New Kit won't Run thru Self Test

I am going to check the PSU tonight. Does the PSU power the hotend seperate from the steppers?

Napsal : 10/04/2018 6:52 pm
Sam
 Sam
(@sam-14)
Active Member
Topic starter answered:
Re: New Kit won't Run thru Self Test

I have checked the PSU and there is 24v on both wire sets to the einsy board. I have checked and rechecked all wires and connections. Is it possible the replacement board is faulty too? Does anyone have any suggestions?

Napsal : 11/04/2018 12:34 am
hilary.s
(@hilary-s)
Active Member
Re: New Kit won't Run thru Self Test

Have you checked the fuses? Does the display show room temperate for the Bed and Hot end? In my case room temperature is about 23 C.
The 15 A fuse is for the Bed.
One 5 A fuse is for the Extruder heaters and fans.
The other 5 A fuse is for the steppers and logic.
This makes it possible to power the Steppers and logic with no power getting to the fans, extruder heater, and bed.

Napsal : 11/04/2018 8:22 pm
Sam
 Sam
(@sam-14)
Active Member
Topic starter answered:
Re: New Kit won't Run thru Self Test

Yes I have checked fuses several times. The thermistors are connected and operating, they will display temp changes if I apply any heat to them externaly. I have power from the PSU to the board. If I skip seltest and go to preheat or temperture settings I get no power to hotend or heatbed.

Napsal : 12/04/2018 12:37 am
hilary.s
(@hilary-s)
Active Member
Re: New Kit won't Run thru Self Test

This sounds like an interesting/annoying problem. I would recomend the following tests to start ruling our individual pieces of hardware and/or sections of hardware as possible culprits.

When you checked to make sure 24V was present on both power leads to the board, did you also check to verify that the ground lines are good?

With the bed and extruder heater disconnected, what are the Ohm readings across their leads correct?

With power connected is there 24V at the fuse terminals? At the Bed and Extruder Plugs on the board? The mosfets that control the heaters switch the negative side so 24 volt should be available when checking from the Positive plug terminal to ground.

With the heaters commanded on, do you detect 24V between the positive and negative plug terminals on the board?

It is possible, however unlikely, that you received two faulty boards. I would also try different firmware versions and try downloading fresh copies of the firmware. If you have the skill you could try customized firmware which would allow additional testing of the mosfet control signals, as well as testing the traces and other electrical components on the board, however those tests require a decent level of skill troubleshooting printed circuit boards and programming.

Napsal : 12/04/2018 4:57 am
Chattel
(@chattel)
Eminent Member
Re: New Kit won't Run thru Self Test


This sounds like an interesting/annoying problem. I would recomend the following tests to start ruling our individual pieces of hardware and/or sections of hardware as possible culprits.

When you checked to make sure 24V was present on both power leads to the board, did you also check to verify that the ground lines are good?

With the bed and extruder heater disconnected, what are the Ohm readings across their leads correct?

With power connected is there 24V at the fuse terminals? At the Bed and Extruder Plugs on the board? The mosfets that control the heaters switch the negative side so 24 volt should be available when checking from the Positive plug terminal to ground.

With the heaters commanded on, do you detect 24V between the positive and negative plug terminals on the board?

It is possible, however unlikely, that you received two faulty boards. I would also try different firmware versions and try downloading fresh copies of the firmware. If you have the skill you could try customized firmware which would allow additional testing of the mosfet control signals, as well as testing the traces and other electrical components on the board, however those tests require a decent level of skill troubleshooting printed circuit boards and programming.

I having the same problem as Sam. My self test passed the fans but fails at the next step saying "Heater/Thermistor Not connected"
The bed assembled well and I'm fairly confident there are no pinched or damaged cables.
All connectors appear good and pass a tug test.
All fuses are good
There is 24V at both pairs of PSU terminals
If I warm the bed, the temperature increase is shown so the thermistor is good
If I set the bed to 50, nothing happens and there is no voltage at the terminals. Eventually I get an error.
I would like to test the ground as advised, but I'm not sure how to do that.
I haven't updated the firmware yet.
Any help would be most welcome!

Napsal : 13/04/2018 6:36 pm
Chattel
(@chattel)
Eminent Member
Re: New Kit won't Run thru Self Test

Success! Well sort of... I run the self test wizard several times prior to my previous post and took several steps that established the EINSY was not delivering any power to the bed heater. So I had a beer, went to bed and tried again the next day whilst getting in contact with tech support. And this time it worked. But I have no idea why. I did nothing. Tech support was only asking for photos. The only difference was that the ambient temperature was 27, up from 25 the previous day. Now I am both relieved and worried since there was no explanation and I am left with a feeling that anytime I might get a hotbed that fails to heat. 😕

Napsal : 15/04/2018 2:55 am
Sam
 Sam
(@sam-14)
Active Member
Topic starter answered:
Re: New Kit won't Run thru Self Test

I tried pre heating like you did but no success. Prusa support thinks it is the board and they are sending another one to me. I sure hope that works!

Napsal : 16/04/2018 6:17 pm
Chattel
(@chattel)
Eminent Member
Re: New Kit won't Run thru Self Test

I mentioned this to a tech friend that thought it might be due to powering up the on-board memory that is used to remember information during power outages. He has come across cases where new equipment would not run until it had been left powered up for a few hours to 'charge' the memory.

I really have no idea if this is a viable answer, but it is consistent with my problem and 'solution'.

Napsal : 16/04/2018 9:17 pm
Nikolai
(@nikolai)
Noble Member
Re: New Kit won't Run thru Self Test


I mentioned this to a tech friend that thought it might be due to powering up the on-board memory that is used to remember information during power outages. He has come across cases where new equipment would not run until it had been left powered up for a few hours to 'charge' the memory.

I really have no idea if this is a viable answer, but it is consistent with my problem and 'solution'.

It works different on Prusa. Any initial static and memory information is being burned during flashing on the ATMEGA chip. Power fail-safe is not being memorized. It's being written during the power outage (couple milliseconds are enough for that).
So it doesn't matter if Prusa is running 24/7 or only couple seconds until you see the init screen. It's in the same state.

Often linked posts:
Going small with MMU2
Real Multi Material
My prints on Instagram

Napsal : 17/04/2018 1:25 am
Chattel
(@chattel)
Eminent Member
Re: New Kit won't Run thru Self Test

[/quote]
It works different on Prusa. Any initial static and memory information is being burned during flashing on the ATMEGA chip. Power fail-safe is not being memorized. It's being written during the power outage (couple milliseconds are enough for that).
So it doesn't matter if Prusa is running 24/7 or only couple seconds until you see the init screen. It's in the same state.
[/quote]

Thanks for the explanation! Now I'm back to not knowing why it didn't work and then it did.
But worse still I have now had a Thermal Runaway fault on a 10 hour run after about 1 hour. Since then all tests seem okay, but there is something wrong and I like some idea of what before I waste more filament

Napsal : 17/04/2018 8:12 pm
Nikolai
(@nikolai)
Noble Member
Re: New Kit won't Run thru Self Test

I would suggest you find a faulty part before wasting more filament.
If you have temp runaway on the heat bed, it's most likely either the cable or connector. If you don't find the issue, replace the cable.
Your issue is crying for a broken cable. "sometimes working, sometimes not".

Often linked posts:
Going small with MMU2
Real Multi Material
My prints on Instagram

Napsal : 18/04/2018 12:50 am
Chattel
(@chattel)
Eminent Member
Re: New Kit won't Run thru Self Test

Tech support have helped me here and it seems the two issues are unrelated.

Issue #1 is that there was no power to the bed heater terminals when the wizard was first used after I completing my Mk3 kit. But once it began to work for no apparent reason the following day, it has been okay since (fingers crossed). It's not a case of 'sometimes good sometimes not' but whilst the cause remains unknown, it doesn't seem symptomatic of a damaged cable.

Issue #2 where I had a Thermal Runaway when printing an array of small objects in PETG, it seems there are some issues printing PETG with this machine due to the heaters on the bed and/or nozzle not being able to keep up with the power demand. The workaround is (1) set the bed to 75 C max. (2) Don't set the fan to 100% (3) If printing small parts, singly or in an array, keep them away from the center of the bed where the sensor is located. (4) ensure your ambient temperature is above 20 C.

I managed to get a smaller array of prints out based on this advice, but I will need to churn out some more so I will be increasing the array size and hoping it is not going to recur. Once aware of the problem it's easier to deal with.

Still worrying about issue #1 though....

Napsal : 18/04/2018 1:38 am
reid.b
(@reid-b)
Reputable Member
Re: New Kit won't Run thru Self Test


Issue #2 where I had a Thermal Runaway when printing an array of small objects in PETG, it seems there are some issues printing PETG with this machine due to the heaters on the bed and/or nozzle not being able to keep up with the power demand.

I don't believe there is an issue with the MK3 being able to keep up with the demand. I have some PETG that requires 270 nozzle and 90 bed, and I have no issue keeping these temps up in a mancave that sits around 21 degrees.

Napsal : 18/04/2018 5:09 am
Nikolai
(@nikolai)
Noble Member
Re: New Kit won't Run thru Self Test

Actually it's a good point about issue #2. I had something similar with ABS. If you print a small part and let the part cooling fan active after the second layer 100%, heat bed will cool down. It's not able to keep up 100C while fan is blowing 100% on it.
I'm glad you got a good online support from Prusa.

Often linked posts:
Going small with MMU2
Real Multi Material
My prints on Instagram

Napsal : 18/04/2018 5:26 am
Hisashime
(@hisashime)
Active Member
Re: New Kit won't Run thru Self Test

The problem comes from the power panic board at the psu. Unplug the black & white wire at einsy board and printer perform flawlessly. Prusa need to look into this major issue. It’s this power panic board that cuts the power to both heaters.

Napsal : 21/04/2018 4:29 am
Sam
 Sam
(@sam-14)
Active Member
Topic starter answered:
Re: New Kit won't Run thru Self Test


The problem comes from the power panic board at the psu. Unplug the black & white wire at einsy board and printer perform flawlessly. Prusa need to look into this major issue. It’s this power panic board that cuts the power to both heaters.

Ben you are the man!! I did what you said and it works now! I can't tell you how many times I have been online with Prusa Support about this. Thank you for your help.

Napsal : 21/04/2018 7:01 pm
Hisashime
(@hisashime)
Active Member
Re: New Kit won't Run thru Self Test



The problem comes from the power panic board at the psu. Unplug the black & white wire at einsy board and printer perform flawlessly. Prusa need to look into this major issue. It’s this power panic board that cuts the power to both heaters.

Ben you are the man!! I did what you said and it works now! I can't tell you how many times I have been online with Prusa Support about this. Thank you for your help.

Still PRUSA TECHNICAL Need to solve this BUG!! Can they hear US!

Napsal : 24/04/2018 8:59 am
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