Geeetech

I replaced the hotend also and it printed a dozen or so prints perfectly until yesterday. While printing a new coaster design, it let out a whimper and a puff of smoke and stopped mid print. I am going to try to get Geeetch to make it right with a new board since this junk is only two months old. I have already ordered another Ender 3 but I do like the ability to print multi color. I am sure that the mainboard is toast. I will say that I have had one problem after another with this printer. I have a Monoprice, an Ender3 and an Anycubic that have not had nearly as many issues as this printer. I hope the Geeetech improves on this design. I feel that it could be a good design if they would use a little better components and redesign the hot end. The current design is way to prone to clogs.

Thanks for your feedback,
Can you describe the problem that occurred?

The hot end tended to clog if you blew on it to hard. It would clog every other print. I had to clean it so many times that the screws became stripped. I ordered another hot end and installed it. It worked beautifully for around twelve prints and then I was printing a coaster and the thing just smoked from the case that the main board is in and quite printing and the display went black. The only fan that works is the one on the PSU. The display is totally black although it will light if you move any stepper motor by hand. The board has only one light next to the power cable that is lit. The other two that should be lit are out. I have checked the PSU on another printer and it is fine. I will bet that the main board is toast. I purchased this printer in May and have had to replace a stepper motor, hot end, bed leveling springs, two of the pulleys, a y limit switch that snapped when it crashed. I had to adjust the stepper motor drivers voltage up due to layer shifts from nozzle oozing. The nozzle oozes so bad that it leaves blobs on the print and catches the nozzle and layer shifts. I fixed that issue with massive amounts of filament retraction 10mm as apposed to around 5mm for every other printer on the planet. I firmly believe that you hot end design is flawed and that changing the angle of the filament from such a sharp turn in the nozzle to more like a Y configuration would help a great deal. I have learnt how to make this printer work after over a month of trial and error and then it blows up after only a week of being able to actually get usable prints from it. I do like this machine because the concept is very novel. Could you help me to keep it alive?

If only one LED is lit, I expect the fuse to be worn.

I strongly wonder if you have such a bad luck, or just don't have a talent for do-it-yourself.
Let's expect you to be unlucky.

He proposes to thoroughly examine the heating circuit and temperature measurement in the hot end.
Look for short circuits and weak contacts in the connections. A multimeter will be helpful.