Clément Dfrd shared with us a new tutorial to fix the second issue with i found on the Anet3D V1.7 motherboard (It is rare but can happen sometimes…)
Please check your motherboard before starting this tutorial. You should get the same pcb as upper.
If you read this part 2 before part 1, please read part 1 to verify all connections between terminal blocks, power mosfets, and all of the above components. This will resolve any potential weld issues that I may have encountered.
First, you have to find the Diode D3 which you can see circled in green below:
During my tests i detected a bad connection between the diode d3 and the track on the printed circuit. I realized there was a through-hole which is a good technique to root the pcb.
The trough-hole via is really close to the diode d3. I can even say that the diode d3 is above the via, which is a technique to save space on the pcb.
Unfortunatly, after examination i found the problem which is well known in pcb industry.
When the solder paste is really hot it liquefies to make the connection between the component and the pcb. But sometomes, the solder paste falls into the via and no longer makes the connection between Diode D3 and the track below.
I think you now understand the problem.
Take out your soldering iron and let’s solder: D
Now is the time! Take your favorite soldering iron and some tin. Stick your soldering iron on the paste of diode D3 and add tin delicately without adding too much. You should have a nice weld forming. Now do the same operation on the other side of diode D3 to be sure that all the welds are perfect!
Last step, clean your solder with some isopropyl alcohol. This step is really recommended to remove any solder flux that may remain after a solder.
Here is a link of a great isopropyl alcohol which i used, it is 99.9% which is the best to me :
I hope this to tutorial will help you to fix your heating issue. This repair is really very easy to perform and you can do it very quickly! I machined the work so that you can quickly get your machine working.