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Problems with thermal runaway after upgrading to 2.5s  

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scott.d3
(@scott-d3)
Active Member
Problems with thermal runaway after upgrading to 2.5s

Hello again.

I just upgraded to a 2.5s from a 2. 

I am  having problems with thermal runaway when printing with PLA. PETG and ABS print fine, but PLA always triggers TR. I usually print with standard PLA settings (60 deg. bed and 215 deg. HE)

I can get prints to work if I run the fan speed at 65%, but this might be ideal for some prints. 

Does anyone have any suggestions?

 

Thanks!

This topic was modified 2 years ago by scott.d3
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Posted : 27/10/2019 3:25 pm
JoanTabb
(@joantabb)
Moderator
RE: Problems with thermal runaway after upgrading to 2.5s

I opened the plastic cover on the bottom of my powersupply and increased the voltage to 12.9 volts using the small variable resistor by the connection terminals.    (About 5 years ago) it's still working fine  🙂

Joan

 

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK...
Posted : 27/10/2019 5:18 pm
heinzk
(@heinzk)
Active Member
RE: Problems with thermal runaway after upgrading to 2.5s

Hi @scott-d3 - I don't much of a suggestion, but seeing the same issue I was wondering how much your temperature dropped after the first layer, so when the fan kicks in. I was pretty surprised that while the nozzle temp should drop from 215 to 210 the fan actually made it drop to 198 in the blink of an eye, and then it took around 2 minutes (quite a few layers in my small print) to get up to 210. Needless to say that the PLA prints didn't really work well - PET on the other hand worked fine.

I didn't have these issues before upgrading from MK2.5 to MK2.5S, and a pal of mine reported the same with his upgrade from MK3 to MK3S ...

(edit) I tried it with the fan speed set to 90%, seems that I was a bit overcautious, so I'll go lower.

This post was modified 2 years ago by heinzk
Posted : 25/11/2019 5:24 pm
heinzk
(@heinzk)
Active Member
RE: Problems with thermal runaway after upgrading to 2.5s

Actually the thread in https://forum.prusaprinters.org/forum/original-prusa-i3-mk2.5s-mk2.5-assembly-and-first-prints-troubleshooting/thermal-runaway-4/ was the right explanation for me - installed a silicone sock, ran the PID calibration and the first PLA print without any further adjustment was quite a few leagues above the prior ones (quality-wise) ...

Posted : 29/11/2019 7:32 am
AgentPayne
(@agentpayne)
New Member
RE: Problems with thermal runaway after upgrading to 2.5s

I finished my 2.5 -> 2.5S upgrade last night and had the same issue.  I restarted the print and watched the temp from from 210C to 196C in seconds when the fan kicked in and instead of going back up a few seconds later it dropped to 195C.  I lowered the fan from 255 to 166 and then the temp slowly climbed back up to 210C.

The first thing I did after that was come to the forums and found this thread so I tried putting the silicone sock on the hot end and running a PID tune.  Now the drop is less than 5 degrees and it pretty quickly returns to 210C so I'd say that was the solution for me as well.

Posted : 11/12/2019 2:56 pm
heinzk
(@heinzk)
Active Member
RE: Problems with thermal runaway after upgrading to 2.5s

It is indeed @agentpayne, I had quite a few prints with the silicone sock and they are all back to the same good quality as before the upgrade 👍 

Posted : 11/12/2019 4:01 pm
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