XL crashes/reboots during heater calibration  

RE: XL crashes/reboots during heater calibration

Update:  Both power supplies measure 23.89V at the build plate.  I was also manually able to get the heated plate to 115C by going up 5 degrees at a time, waiting until the temp was reached, and then doing 5 more.  NO problem.  Extruder passed its portion of the test once (others were short-circuited by the failing modular bed).  

After crash/reboot, a red !ERROR screen is shown entitled "MODULAR BED ERROR" followed by "Power failure".  A link is given:  More detail at https://prusa.io/17319.   This is the same target as the QR code.  This page DOES NOT EXIST - I am redirected to http://prusa3d.com.   I also see the firmware version: 4.7.1, and a code: R1KEKFPR and on the right of that a [A].

From what I can tell, when the modular bed pulls too much current, something panics and the device is reset (about 85% of the time it does that - the other few times I've finished the calibration test with a red 'x').

5V Voltage still shows 33.3V.

RE: XL crashes/reboots during heater calibration

From what I'd say one square of the modular heat bed is playing up contact support through live chat ps are you sure the 33 33isint 3.3 volts try clicking range on multimeter and see if it reads 3.3

RE: XL crashes/reboots during heater calibration

I can certainly check to see if the display is wrong and it actually means 3.33 instead of the displayed 33.3, but where are the 5V leads?

Also, I'm not sure why I'd be able to incrementally get the heated bed to 115C but not do it quickly.  

Let me know about where the 5V leads are,  my voltmeter is ready to go.

RE: XL crashes/reboots during heater calibration

Read it the same place you were getting 33 volts also turn printer on cold try start a small print in the middle and move it around the bed to test each section of the bed dont preheat first just start the print as I reckon it may be a faulty square in the bed

RE: XL crashes/reboots during heater calibration

I can confirm it should be reading 33 to 34 volts

RE: XL crashes/reboots during heater calibration

@jerduobro, I tried your method of incrementally heating the bed and I was able to successfully raise the temperature. If I moved in more than 1 degree increments, I would get the modular bed error. I was only patient enough to do 1 degree increments up to 60C. Then I tried increasing the amount by 5-10 and I got the modular bed error again.

RE: XL crashes/reboots during heater calibration

Just thought after you do the above test printing on each square for the xl to reboot it either needs a hardware or software glitch maybe something on the bed is shorting as when the mk3 shorts something it reboots let me know the test results gtom the print test and we'll go from there

RE: XL crashes/reboots during heater calibration

I'll do that - w/o calibration I suppose should be ok?

I ran the behavior across some other folks - opinion was that it sounds like a power supply is not handling the draw, drops below a threshold voltage when drawing high current, and the main board powers off due to undervoltage.  Theory.  I'll also try to measure bed voltage while the calibration is on going to see if this is provable.

RE: XL crashes/reboots during heater calibration

@jp-6, that stinks.  It sounds like your situation is even more sensitive than mine.

Update: 

1) Power supply voltage does not significantly drop upon crash.  From 23.88 to 23.54, and then crash.  I tested both 'legs' supplying the heated plate.  Same.

2) In trying to do isolated prints (despite all the "you haven't finished calibration" warnings) I was partially successful.  I started with a small 40mm object in PLA - prompting various portions of the bed to heat to 60c that I could place on any heated square.  Starting in the front left, good.  second row back, left, good.  front row, both middle right and right, good.  Attempted 4 heated squares - front and second rows, middle right and right:  FAIL - immediate reboot when the print started, same error when calibration fails - modular bed error, power failure

3)  attempted manually putting all the heated bed to 60c - immediate crash.

Current theory:  When current draw is too high, failure.

Next test:  4 other heated squares in already-proven parts of the heated bed, and then combinations to see where the threshold is / see if it's in one specific spot or not.

RE:

Update:  Tested many combinations of objects to selectively power/not-power specific squares from the 4x4 grid.  In each case, the object required a 60C bed.  Red indicates the printer rebooted during the bed heat-up process.  Green indicates the printer did not reboot, did reach 60C, and started printing.  

As a reminder, I have been previously successful heating up the entire bed to 115C, but only 5 degrees at a time.

Here are the preliminary results

RE:

OK so it's a power supply issue live chat with prusa they may send you new psu

RE: XL crashes/reboots during heater calibration

Or they may send you new mother board it is because power is to low for the board to operate si it resets maybe check the wiring of the 2 psu

RE: XL crashes/reboots during heater calibration

I'm not sure why it would be a power supply issue.  I've powered up 8 squares at a time successfully, and then not 1 specific square from that same set.  Seems that if it were a supply issue, it would have more consistent behavior.  I'm not sure root cause can be determined yet.  Though yes, chat might be the best route.

Posted by: @hello

OK so it's a power supply issue live chat with prusa they may send you new psu

RE: XL crashes/reboots during heater calibration

It's either power supply issue or a short otherwise the buddy board wouldn't reset

RE: XL crashes/reboots during heater calibration

Well, bad news.  I did have two yet-unused 24V 350W meanwell power supplies on hand from an old DIY project, so I went about hooking them up.  All went swimmingly connecting them to the PDU, until I got to the power panic connectors.  Seeing the V+ and V- connections, I just wired them up too (this was a mistake).  As soon as I flipped the power switch on - poof, smoke, small flame on the power panic circuit part of the sandwich board.  Maybe the transistor.  Unlike.  Printer does power on but complains about the power panic cable not being connected correctly (I re-connected it to the original power supply which was still powered by the PDU), which I can't get around.  Looks like I'll need a new sandwich board.  I really with the printer would have just worked.

RE:

I am also experiencing this issue. I can complete small prints like the batarang just fine, but larger prints cause the panic. I can complete the heater test most of the time, but then finishing the test and raising the temp to 110 causes a panic some time later, not immediately.

I don't think it's a short cause each tile heats, it could just be overly sensitive current monitoring. Although, there is quite a loud transistor buzz when heating the bed...

Re. The 33v, I also see that reported on the display. I have not measured it anywhere. How was it confirmed that this is correct? I doubt it's correct, considering it's next to a label that indicates it should be 5v. Either the label is wrong, there is a missing decimal place, or something else isnt right. (That would be my 4th issue)

RE: XL crashes/reboots during heater calibration

Oh that doesn't sound too good

RE: XL crashes/reboots during heater calibration

I removed and reassembled my bed, and I can now reliably heat the whole bed. While reassembling I trapped a cable during step 18. I noticed and fixed it, I can only assume I made the same mistake first time 

RE: XL crashes/reboots during heater calibration

Spoke too soon. It was working fine, I leave it for a few hours, and it's now exactly the same as it was. Disappointing.