Provok3d MagBed(Boxxy Bed) Thermistor Issues

[sand marsh]

I could use some help from you smart people

trying to replace my LDO bed again with the provok3d magbed(boxxy bed) - I've come into chat before with this issue, cant figure out the thermistor

The hole in the back of the bed is apparently too big for a Mellow M3 PT1000, it just wiggles around in there, the hole doesn't seem to have threads

https://provok3d.com/product/voron-2-4-trident-bed-system/?v=7516fd43adaa

product page says M3 hole for "Cartridge PT1000" which I can put in there and it fits what I consider Perfect, goop the hole with boron nitride paste and slot the PT1000 in

Going to try and explain the best that I can
The thermistor does NOT function correctly at all in Klipper, it won't register temp changes very quickly at all - if I set it to say 40c and it starts at 30.9c it takes multiple seconds to register even a 0.1c change
It will take a few minutes to get to 40c and then cut off power, but the temp continues to climb and climb for roughly 10-15 minutes after
The bed is also much hotter than 40c based on feel(lost my temp gun) feels more like 60-70c

Will attach pics of the bed with/without thermistor cartridge and provide current bed cfg in klipper

##  SSR Pin - HEATBED
##  Thermistor - TH1
heater_pin: PG11
sensor_type: PT1000
sensor_pin: PA2
pullup_resistor: 2200
##  Adjust Max Power so your heater doesn't warp your bed. Rule of thumb is 0.4 watts / cm^2 .
max_power: 1.0
min_temp: 0
max_temp: 145```

This is why I consider it a perfect fit, as you can see the cartridge just slides in perfectly fitting

Using the guides recommended Wago for the Bed wiring on the left, ignore the right side - its my bed fans

again the Mellow M3 PT1000 is too small for the hole, doesn't thread or stay in the hole - so I think it's definitely wrong for multiple reasons, just a long shot on my end

[scenic holly]

I just slid a pt1000 in with some boride paste

It doesn't need to be threaded

[sand marsh]

I've done that too, it fits perfect - but it doesn't seem to read realtime

[scenic holly]

I use MPC for the bed and no issues forever. My config has my settings for hysterisys or whatever

[sand marsh]

I'm using regular klipper, is MPC an option for me?

[scenic holly]

Nope.

[sand marsh]

I moved to kalico - running an MPC calibrate now

[sand marsh]

Going to bed for now - issue not resolved, MPC calibration adc's out because the heater never starts back up during the second part
going to replace PT1000 tomorrow after work and test some more

[willow willow]

I'm way late to the party here but you definitely should not use a thermistor mounted in the aluminum plate for your heater sensor. As you have discovered it lags so far behind that you can get such huge swings in temperature that even a pid tune cannot compensate for. Thermistors in the plate are great as references but the sensor for the heater control needs to be mounted to the heater pad itself.

[scenic holly]

None of the boxxy beds work that way

[sand marsh]

Every person I've spoken with so far that owns one of these beds has had the experience of putting a thermistor in the slot of the plate and it just works. Sure its at the edge so it will lag behind a bit or overall, but it just works for them.

What I'm seeing is such a huge disconnect and massive lag that it does indeed just rise and rise and rise, and I don't have the total issue narrowed down - but my recent theory is the 1200/1300w heater pad it came with.
Ordered a 750w heater pad and I've put this on hold as I have zero other ideas.
Tried replacing the P1000 thermistor but had the same issue, so I know those are both fine as one was my chamber thermistor before hand.
If that doesn't work I'll slap a fabreeko edge to edge heater on the plate and just figure it out from there.