Help with CR10 3D printer Diagnosis/Repair

I have been using Kevin S.'s CR10 to print some models for work. The last few models have failed to complete, apparently because the heated bed is failing intermittently causing the parts to detach from the build plate.

I am not sure how to go about diagnosing and/or repairing the heated bed. Does anyone have any Idea of what steps I could or need to take? Would anyone with experience with these things mind coming in to help me out (I’ll be in tonight and Saturday)?

Thanks,

Kevin M.

I am likely going to have to build an enclosure for the printer as well as get some decent build tak / bed adhesion material. The printing material and company can also cause some frustrations with adhersion on large prints.

So, I'm pretty sure it's something electric wrong though, because it's showing a commanded temp of 60c, but actual temp below 35c

Kevin,

Ryan might know what is up with it best then. He was using it for a bit before he brought it down to the hive. I have not printed on it for a long while so it could be the bed element, board, or firmware. Did you try heating the bed manually in thr menu options when not printing to see if it would warm up?

Yeah, it sometimes would, sometimes wouldn't. Makes me think it's bad cable or connection

I disassembled and reassembled the bed and control box to check all the connections, and visually everything looked good. I reassembled everything and it heated for about 10-15 minutes then stopped and cooled back to room temperature. I don't know if it's the cable, or the MOSFET board, or a connection I missed, but it's trying to heat to 45 degrees, but not actually getting warm now.

Is the temperature reading correct

It's reading around 25-28c, and it feels like room temperature to the touch, so I assume so.

It sounds like the issue isnt the thermostor then, The Mosfet could have blown as well as a broken wire. (Heating element is possible, but not as likely based off of what you said.)

I have a pretty good selection of MOSFETs here if you can identify which one it is.
-D

Here is the official Creality Mosfet:
https://www.aliexpress.com/item/Official-Creality-3D-CREALITY-3D-CR-10-CR-10S-CR-10-S4-CR-10-S5-Mainboard/32837212837.html

I found a replacement https://macewen3d.com/products/creality-cr-10-replacment-mosfet-for-heater-bed

Used a IRF3205. It’s a bog-standard N-FET. I am 99.9% sure I have something that is several orders of magnitude more efficient / less heat-dissipating sitting around.
-D

If the MOSFET blew, would it have cut in an out like it did? I assumed if a MOSFET failed that was just the end of it.

Check its temp and be careful not to burn yourself.
-D

If a connection is lose, it can cause that either on the board or a wire.