heat bed stopped heating mid print. connections all seem good and solid under the printer. the light on the SSR turns on when i tell the bed to heat, but no heat happens. What should be checked next? Thermal fuse or something else?
#heater bed stopped heating
distant light
potent apex
Thermal fuse is likely the most common issue yes. Could be a couple of things like the heater went bad too. Check the bed resistance and let us know what it is please.
distant light
can i measure the resistance of that without taking the bed off and just use the connections under the printer to test it?
potent apex
For now. We probably will need to take the bed off if it shows nothing.
To test on the other side of the fuse
distant light
No reading on the multimeter. It just stays at 1
potent apex
Then I would suggest taking the bed off and measuring the wires after the fuse. See if you get something. Plus visually inspect the bed for burn marks
distant light
i should be checking for resistance between both of the wires coming off the bed correct, the hot and the neutral.
potent apex
Correct
distant light
getting about 20ohm on the other side of the fuse.
wire got cut when i was taking the heat shrink off to get at it to test, thats why the exposed part is short
that little bit of brown on the hot wire to the heater concerns me a little?
potent apex
But nothing through the fuse? That's an answer.
distant light
nothing through the fuse
when iw as taking the bed out i noticed the ground connection underneath was slightly loose, could that be what caused it?
potent apex
when iw as taking the bed out i noticed the ground connection underneath was sli...
Those thermal fuses are pure chinessium. They just fail.
distant light
so replace the fuse obviously. is that bit of discoloration on the hot wire of the heater a concern?
potent apex
Almost looks like it shortened, then blew.
I would not worry, assuming you strip it back and properly connect it to the fuse, with maybe a wago.
distant light
and if the ground was loose, that could explain a short?
potent apex
and if the ground was loose, that could explain a short?
Generally no. The short is likely the fact thermal fuses are pure chinessium.
Ground not connected is a safety issue yes, but only if the neutral is broken.
And the fuse should be on the live.
distant light
cool. just wanted to figure out if i could find the reason for the short before repairs/putting back together.
is there a better thermal fuse to put in, or should i just order a few spares?
potent apex
Order a few spares. Unfortunately I've found two tiers. Affordable but likes to blow for no reason, or $$$ but reliable.
I'd go a little higher in temp. 140 or so to allow for variance in quality control.
distant light
how much $$$ we talking for reliable?
potent apex
I honestly don't remember, I just remember it's way more than I'm willing to spend.
distant light
I'm seeing these at $5 instead of the $1.30 for the direct replacement. https://kb-3d.com/store/heated-bed-electronics/4070-alpha-therm-thermal-fuse-150c-trip-temperature-ceramic-1634486081131.html
potent apex
I'm seeing these at $5 instead of the $1.30 for the direct replacement. https://...
Really it's the same quality or close. Maybe worth a shot. Kb is a great vendor
distant light
well i'm going to go with that heater is bad. thermal fuse blew again, got like 8 hours of prints in good, started a new print this morning, and then went to check and everything shut down.
thermal fuse is shot, the cable came off the fuse and i think shorted to the bed. It popped the GFCI on the circuit, and the fuse on the inlet.
radiant grove
having a similar issue. Though in my case I don't see the SSR's light turn on in my case. And it was working prior, when then I set the bed to I think 105-110 (don't remember) to print ABS. I smelled something odd but thought it was the ABS. My only thought are that either the SSR died or the MOSFEt I had it plugged into to control it died in the off position (thankfully)