Fused my recently bought MK2.5S heatbed. Can I downgrade and use a MK2 heatbed?
 
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Fused my recently bought MK2.5S heatbed. Can I downgrade and use a MK2 heatbed?  

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Jonathan Avel
(@jonathan-avel)
Active Member
Fused my recently bought MK2.5S heatbed. Can I downgrade and use a MK2 heatbed?

Hey fellow 3D printing friends,

I upgraded 10 months ago from a MK2 to a MK2.5s and the heatbed recently caused some trouble and eventually broke. I reprinted the cover when the printer started smelling a bit funny and the printed heatbed cover melted at one of the connectors. I also replaced both connectors with a new set of cable shoes to ensure a proper connection, but things didnt improve. I suppose there must have been some irreversible damage to the heatbed connection and/or resistors close to the connection, although the copper connection points seemed to be fine. The heatbed connection area turned brown and scarred, the heatbed is unusable now.
I am now kinda on the fence whether I should be spending close to 100 Euros for a complete heatbed replacement. Since I was never 100% happy with the upgrade (I had recurring trouble with the z-probing at the start of the print, thus could never use the latest firmware as it was near impossible to get a print started), I was wondering if it was possible to switch back to the old MK2 print bed that I still have. Would it cause trouble with the new PINDA 2 or the new board or could I get it to work?

 

Best regards

Dom

Posted : 14/10/2020 8:15 pm
Chicago Keri
(@chicago-keri)
Estimable Member
RE: Fused my recently bought MK2.5S heatbed. Can I downgrade and use a MK2 heatbed?

Sorry to hear about the bed.  

Unfortunately, the Mk42 bed will likely fail initial calibration after assembly because the PINDA sensing points are in slightly different places on the Mk52 bed.  The Mk52 bed actually has fewer sensing points on the bed itself, as the initial calibration is done with fewer points on the 2.5.  

If you just neglect to re-calibrate after changing the bed, it might work if the Mk42 sense points happen to line up during mesh bed leveling. Of course the height is likely to be way off, but that is easily remedied.  Mostly, I suspect that the pre-print bed leveling will fail.

The mesh bed leveling before ever print uses the same number of points but the PINDA will detect the Mk52 steel build plate basically anywhere and the Mk42 bed has to be almost perfectly centered on every measurement point .  

You could just flash the 2S firmware to the MiniRambo but then you lose the use of the filament sensor, the 5v speed detected hotend fan and the temperature-compensated PINDA.  The new PINDA 2 could be connected as a PINDA 1, I think.

I would look into buying a clone 12vMk52 bed.  

 

¡no entiendo Español!
Nein! Nicht Versteh!
Я немного говорю по-русски но не очень хорошо, и...
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Posted : 16/10/2020 1:59 am
Same Old Shane
(@same-old-shane)
Member Admin
RE: Fused my recently bought MK2.5S heatbed. Can I downgrade and use a MK2 heatbed?

Without seeing a photo of the heat bed power cable conneciton to the back of the bed, it is difficult to say for sure, but if those get loose, they can overheat to the point of melting the plastic covering and will continue to heat up. If you can provide the photos we might be able to take a look and see if just the terminal connectors need to be replaced or something else.

By chance, did you double check the heat bed connection on the Rambo board to make sure there wasn't any melting on both connectors? (On the board and on the cable) as that will also heat up if loose.

I know its a bit too late, but it is a good habit to check your printer every 200 hours and preform regular maintenance on it to keep it in good form and to make sure not cables are starting to loosen up due to the movement of the printer

 

https://help.prusa3d.com/en/article/i3-printers-regular-maintenance_2072

Shane (AKA FromPrusa)

Posted : 16/10/2020 11:02 am
Jonathan Avel
(@jonathan-avel)
Active Member
Topic starter answered:
RE: Fused my recently bought MK2.5S heatbed. Can I downgrade and use a MK2 heatbed?

I am 100% certain that the connection is fused for good, see attached file. As I mentioned, I did replace the cover and the cable shoes, cleaned the connection. But I suspect some element had crossed the line already of being too damaged beyond repair. 

This post was modified 3 years ago by Jonathan Avel
Posted : 16/10/2020 1:23 pm
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