so how is this happening?
Here is what happens/ed on mine.
a) cold unit, turn on bed heat to 110C (doesn’t matter the temp, could be anything), it would run right up there in about 15 mins and hit the temp, reading the correct sensor values in printrun. Then it would say that the bed was cooling and it would show a temp in printrun cooling down to about 70ish and then start to go the other way showing a rise in temp.
b) if you lowered the temp it was suppose to hit, to something lower than what printrun was actually reading, let it run for a few cycles as it showed a lowering trend and turned off the bed, you could then set a higher temp and it would run right back up to it, at which point the whole process would need to be repeated…
My first exposure to this felt like the bed wouldn’t heat past 80C as well… That’s why I spent a whole weekend mucking with it, until I finally sent it back (the bed and controller) so that the gang at lulz could look at it.
if I had it at the moment, I’d try something… build the firmware with eeprom enabled, init to defaults with the M command, save that with the M command and the reboot and then I’d either… a) rebuild for no eeprom and see how it behaved, or b) leave it with eeprom enabled and see how it behaved.
I’m beginning to wonder if there was a software offset that was somehow getting involved (even though eeprom and pid for the bed are not enabled on the default build) and that it’s getting this offset from the eeprom somehow…
When I saw your command about not heating above 80C, it reminded me that mine felt the same way until I figured out the cycle that could make it go above 80…
If on a cold startup it won’t go above 80, then most likely you should get with the gang at lulz and have them check out the power supply… that’s about all it could be unless there is a fuze somewhere and that would show as an all or nothing, not a partial (80C) thing.