BIGTREETECH-SKR-mini-E3
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bigtreetech
Hotbed heating on startup
Installed the SKR mini E3 V3 on my old Hanbot DRT printer. Seems to be working fine except for the hotbed. It starts heating up from the time you power up the printer. The heat keeps going up even if you try dropping it. I updated the firmware as well but no luck. All connections seem fine also. Can anyone assist.
There can be several problems.
- short circuit of the heated bed to the frame
- poorly connected bed
- defective MOSFET switching transistor
- defective pin on the processor
- bad configuration modification before FW compilation
- Bug in Marlin
Check everything in the order in which I listed the options.
Just for info. The positive voltage is permanently connected, the negative potential is switched
bigtreetech
Just for info. The positive voltage is permanently connected, the negative potential is switched
what do you mean here
cannot test for faulty mosfets or processor
Below power connector the is 2 LEDs. the left is permanantly red and the right LED flicks red
when I try to heat the extruder it gives a continuous beep and says HEATING HALTED : KILL CALLED even disconnected the bed totally.
I am using the ender 3 firmware for my printer, will this be ok. attachin printer photo below
Upgraded the extruder to the BTT H2 and using BTT TFT35 display
Did you short the hotbed? Are you sure you know what you're doing? This is how you must burn a Mosfet. Did you use Marlin for Ender? Was this FW designed for your control board? If you are upgrading, it is best to compile your own FW.
Check Mosfet: Unplug the printer. Disconnect the bed heater from the SKR Perform the ohm measurement as shown.
How much did you measure?
Check Mosfet: Unplug the printer. Disconnect the bed heater from the SKR Perform the ohm measurement as shown.
How much did you measure?
Hi radek8
At a setting of 20 ohm on multimeter I get 0.05 and 20k ohm - 5.14 ohm
If you had unplugged the bed and measured these values, it means that you have burned mosfet. There are two solutions. Solder a new mosfet, or use an external mosfet. For external mosfet you need to adjust the configuration
what is the mosfet part number and where do I solder it. I did not touch or short anything that could cause mosfet to blow. there is no shotting I can see
is the board not guaranteed, if I do anything to modify board won't it void warranty
Yes, if the board is under warranty, repairing the board will void the warranty.
If the board is under warranty, contact the seller and request a warranty replacement.
Just installed another new board. doing exactly the same. heating bed at statup Made sure that nothing can touch to cause and sort of shorting
OOPs no there is no short between hotbed and frame
You have a short circuit between the bed heater and the printer frame. You wrote that you controlled it.
could it be the old bed or sensor settings
my hotbed is connected via another small board, can only see a big heatsink on board. is this external mosfet you were talkong about and could this cause the heating on startup. no such errors on origanal board.
Do you have the bed connected via an external mosfet? But you didn't tell me that... :-( Draw a block diagram of how you have it connected.
Why are you using an external mosfet? Does the bed have a different voltage or too much current?
12 : 9,88= 1,21A 1,21 * 12 = 14,5 W What did you measure? Your bed would only have 14.5W I want to know what power your bed has. What current flows into the bed?
12 : 9,88= 1,21A 1,21 * 12 = 14,5 W What did you measure? Your bed would only have 14.5W I want to know what power your bed has. What current flows into the ostele?
how do I messure this?
I probably won't get much information from you.
Your power supply gives a maximum of 17A. So for the bed it will be a maximum of 12A Even the Mosfet on the SKR should withstand that. Try disconnecting the external Mosfet and connect the bed directly to the SKR board on the HB connector
Thanks that worked Now getting error below as soon as you preheat and temperature goes above 210deg
do you have instructions how to level the bed for the skr mini e3 v3
This error occurs if the thermal runaway protection on the ecttruder, which is integrated in Marlin, is activated. There can be more problems that it causes.
Either you have the protection set to fairly critical values, or there is a problem with the thermistor or the heating element.
Send me the Marlin configuration files you used to compile Marlin.
You wrote that you changed the print head... Did you happen to use a printhead with a 24V heater? Did you set the right type of thermistor in the Marlin?
Yes I upgraded to the Biqu H2. is this 12v or 24V what thermistor does it use
You cannot supply the printer component with 230V (110V) It would be dangerous for the operator. Therefore, the printer is fitted with a low voltage source which then powers the component. Printer manufacturers use two standards 12V or 24V. Depending on what source you have, you have to use and buy such components. You have a 12V source. That's why you have to use 12V fans, 12V hotend heating body, 12V bed heating. You have to configure the Marlin for 12V. That's why I ask: What variant of the print head did you buy? How many volts is the heater and fans on your new printhead? If you bought 24V, it may cause the problem you have.
If you want my help, you have to give clear answers to my questions.
In Marlin, you have the power supply wrongly defined. Set up: #define CHOPPER_TIMING CHOPPER_DEFAULT_12V
BIQU H2 V2.0 Extruder Kit
Extrusion method: Double gear extrusion Maximum printing temperature: 270℃ Weight: 211g (including heating aluminum block, fan) Maximum extrusion force: 7.5kg (depending on filaments) Extrusion capacity (based on existing): 600mm³/min(depending on filaments) Number of pulses: 932steps/mm for stepper motor drive at 16 subdivisions (micro-steps) (further correction is required) Recommended motor current: 800mA Filaments' diameter and tolerance: 1.75±0.05mm
Does not specify voltage nor on the box
Is there a fan included in the print head? Did the fan come with the head? If so, take a picture of the fan nameplate.
Or can you measure the electrical resistance on the heating element?
At a setting of 20 ohm on multimeter I get 15.5 and 20k ohm - 0.01 ohm
the heating block was not tapped so can't install grub screws, so I secured it with cable ties so cable can't slip out especially thermistor
the heating block was not tapped so can't install grub screws, so I secured it with cable ties so cable can't slip out especially thermistor
I don't understand what you write. send a photo
Your problem is clear Extruder heating is for 24V If you connect it to 12 V, the heating element that should have 40 W / 24 V only has 10 W / 12 V 10W is not enough to heat the Hotend to a temperature greater than 210°C Therefore, the printer stops. You have to buy a new 12V heater and fan
If you would like to change the power supply to 24V (24V is better :-), you would have to make a bed too. The bed is designed for 12V and with a 24V power supply it would consume 4x more... From the current 110W bed, it would be 440W and that would burn up the heating. 24V source + 24V bed is an expensive upgrade
After you solve the power problem, I recommend calibrating the thermistor. you have type 1 set in FW, but that certainly won't match your thermistor. When I changed my thermistor, the display showed 210°C, but I measured 230°C on the hotend with an external sensor. After calibration to the correct value, the temperature is against reality with an accuracy of 1°C.
When you have the right temperatures, you can deal with leveling.
Unfortunately, I don't use MESH_BED_LEVELING. That's why I won't advise you how to use it. It is too imprecise. I recommend you buy a BL-Touch or a 3DTouch clone.
Before using the printer, calibrate the extruder and do a PID calibration of the Hotend and the bed. Then save the calibrated values to the FW and recompile the FW