¶ Phenomenon
During the preparation for printing, the heat bed temperature does not rise, or the heat bed does not heat up after a heat bed temperature was set.
If the heatbed temperature is 0, you can refer to the key scenario 1 in the wiki to troubleshoot：Troubleshooting of heat bed not heating up | Bambu Lab Wiki
¶ Causes & Solutions
Scenario one: The bed temperature is displayed as 0 ℃. This means that the temperature sensor of the heat bed is abnormal. You may want to check if the NTC thermistor is properly connected and if it has any damages.
Solution for scenario one: 1. Check the connection status of the heat bed NTC; 2. Check the connection status of the connection cable from the heat bed to the MC board;
Scenario two: The bed temperature is not 0. This means that the temperature sensor of the heat bed is normal, which, in turn, means that the heat bed may be faulty, the power supply may be faulty, or the control signal transmission is failing.
Solution for scenario two:
- Check the resistance value of the heat bed. If the resistance value is abnormal, it indicates that the heat bed may have burnt components or an open circuit, and the heat bed needs to be replaced;
- Check the connection status of the power cable and the cable connecting the MC board with the AC power board. If poor contact is found, reconnect the cable(s);
- Check the conduction of the power cable of the heat bed and confirm that the power cable is not damaged. If it is damaged, replace the power cable (or replace the heat bed);
- Check the AC power board. If any components on the AC power board are damaged, or the heat bed and power cord are confirmed to be normal, replace the AC power board.
¶ Safety warning and Machine state before starting operation
IMPORTANT!
It's crucial to power off the printer before performing any maintenance work on the printer and its electronics, including tool head wires, because leaving the printer on while conducting such tasks can cause a short circuit, which can lead to additional electronic damage and safety hazards.
When you perform maintenane or troubleshooting on the printer, you may be required to disassemble some parts, including the hotend. This process can expose wires and electrical components that could potentially short circuit if they come into contact with each other or with other metal or electronic components while the printer is still on. This can damage the electronics of the printer and cause further damage.
Therefore, it's essential to switch off the printer and disconnect it from the power source before doing any maintenance work. This will prevent any short circuits or damage to the printer's electronics. By doing so, you can avoid potential damage to the printer's electronic components and ensure that the maintenance work is performed safely and effectively.
If you have any concerns or questions about following this guide, open a new ticket in our Support Page and we will do our best to respond promptly and provide you with the assistance you need.
1. The heat bed is directly heated by the mains electricity, and there is a danger of high voltage. It is necessary to ensure that troubleshooting is carried out with the power off.
2. If it is found that the heat bed (AC power board) is burnt, check whether the AC power board (heat bed) is in good condition at the same time.
¶ Tools needed
- H2.0 hex key
- Multimeter
- Tweezers
¶ Scenario one - The heat bed temperature is displayed as 0
¶ Troubleshooting suggestions
1. Check the connection status of the heat bed NTC
2. Check the connection status of the connection cable from the heat bed to the MC board;
Note: The connectors of these two cables are fixed with white silicone gel. If there is no obvious tilt or PIN withdrawal, just press again; When you need to disconnect them, you can use a hair dryer to heat the silicone gel to reduce the hardness and then remove the silicone gel or disconnect the cables.
¶ Operation guide (disassembly & inspection)
You can also check if the NTC cable is loose without opening the heatbed.
 |
 |
¶ Step 1 - Remove the heat bed pretension nuts
Unscrew the 3 pretension nuts to unlock the heat bed from the metal bracket. Note that there is also a rubber ring on top of each nut.
 |
 |
¶ Step 2 - Open heat bed
Open the heat bed carefully because of the cable inside, and remove the loose pretension springs.
¶ Step 3 - Check the connection status
During this step, you can check the connection between the heat bed to the MC board and the NTC cable simultaneously. The 2PIN connector is for the NTC cable. It is necessary to check whether the connectors are loose and whether the cables are loose.
¶ Step 4 - Remove the rear panel and excess chute
If the above troubleshooting steps still do not work, follow steps 4-6.
Refer to the related contents of the Rear panel and Excess chute to remove the rear panel and the excess chute.
¶ Step 5 - Remove the cable railing
Remove two screws with an H2.0 hex key and remove the cable railing.
¶ Step 6 - Check the connector on MC board
Check the status of the connection cable on the MC board, and confirm that the connection is not floating and no PIN is withdrawn. After checking and confirming, you can reconnect the power supply and turn the printer on to confirm whether the heat bed temperature is no longer displayed as 0. If the fault is not eliminated, you need to check the connection status of the heat bed.
If the fault persists, you need to contact the service team for confirmation.
¶ Scenario two - The heat bed temperature is not displayed as 0
¶ Operation guide
¶ Step 1 - Raise the heat bed
In order to facilitate this process, we need to raise the heat bed: tilt the printer, and pull the Z-axis belt to raise the heat bed to 2/3 of the way up.
¶ Step 2 - Check the resistance of the heat bed
Remove the 2 screws as shown in the picture below, remove the cover, and use a multimeter to test the resistance value of the two terminals. If the resistance value is between 40 and 60 ohms, the heat bed is normal, and you can go to the next step; otherwise, the heat bed needs to be replaced.
（Click Heat bed to view how to replace the heat bed）
 |
 |
¶ Step 3 - Check the cable connections
Remove the rear panel and the cable cover, and check the connection status of the power cable and the cable connecting the MC board with the AC power board to confirm that the connection is normal without looseness or skew. Then, go to the next step.
（Click Cable cover to view how to disassemble the cable cover）
 |
 |
¶ Step 4 - Check the heat bed power cable
Remove the two blue silicone sleeves and test the resistance value with a multimeter. If the resistance value is between 40 and 60 ohms, the power cable is normal, and you can go to the next step. If the value is different, it means that the power cable is faulty and needs to be replaced (or the heat bed needs to be replaced).
（Click Heat bed to view how to replace the heat bed）
Caution: After measuring, please restore the blue silicone sleeves to keep the plugs insulated.
¶ Step 5 - Check the AC power board
If the above steps are normal, it can be confirmed that the AC power board is faulty and must be replaced.
Of course, if the AC power board has visible damage, this can also be used to determine that the AC power board is damaged and needs to be replaced.
（Click AC board to view how to replace the AC board）
¶ End Notes
We hope that the detailed guide we shared with you was helpful and informative.
We want to ensure that you can perform it safely and effectively. If you have any concerns or questions regarding the process described in this article, we encourage you to reach out to our friendly customer service team before starting the operation. Our team is always ready to help you and answer any questions you may have.
Click here to open a new ticket in our Support Page.
We will do our best to respond promptly and provide you with the assistance you need.