Special Thanks to Clément Dfrd
The issue on the motherboard of Anet A9 (Motherboard Anet3D V1.7) lies to the solder issue. There was no enough solder paste on the mosfet’s pads. The two mosfet which control heat of bed and nozzle are responsible for the heating of Anet A9.
First step to follow before operating on the motherboard is to try to heat up the nozzle to 200°C / Bed to 50°C, if after few minutes the nozzle or bed does not heat up you should follow the next step.
Then, open the printer and localize the motherboard as you can see upper (Anet3D V1.7).
You need and have to use a multimeter tool in order to test continuity. Please take your multimeter and put the continuity test as below:
Test continuity between the screw terminal :
- Positive (+) Nozzle and the « GATE » of the IRLR7843 mosfets
- Positive (+) BED and the « GATE » of the IRLR7843 mosfets
Please watch the example picture below to see how to mesure for NOZZLE:
Now, let’s test the continuity between positive (+) terminal screw of (+) BED & (+) Nozzle, please mesure as below:
If there is no « bip » sound to show you the continuity is correct, please verify solder pads under the terminal screw and add some stain with your iron solder to fix the issue.
If the continuity is correct, please follow the next step.
Last step guys ! Come on!
We need to verify if the « source » pins of the IRLR7843 mosfets are connected to ground.
As below, mesure the continuity between « GND ground » of the terminal screw and each pin of mosfets (in blue color), if you hear a « bip » sound the connection is correct!
If you do not have the continuity please, add some stain solder with your iron as below: