A5S smoking after fans shorted: Help!

vinny98

Last week I was fiddling with the hot end and the wires for the blower fan inadvertently came in contact with the heater block, melted, and then shorted out. No big deal, figured this was the perfect time to improve my part cooling so I looked at the upgrades page, printed a mount for a larger blower fan, and began the install of the new fan. Low and behold the connector wasn't the same so being the genius that I am I decided to magiver it. I took the pins out, wrapped tape around one of them, stuck them in and turned the fan on. It worked for a minute until I moved the cables back into the wiring harness and then snap crackle pop I start seeing smoke coming from the bottom of the printer. There is now there volts/infinite resistance at the connector and neither of my fans work as I screwed up the other one with the same smokey result, because I'm a genius of course. Everything else still works, the bed and hotend heat up, all of the axis and filament extruder work, and the lcd has full functionality. The question is what do I need to replace? The power supply? Main motherboard? Or the circuit board with the three connectors that connect to the fans, thermistor, etc.? 

Samuel Pinches

Oh no @vinny98 - that sounds like quite a troublesome day!  Sounds like the power supply has survived if things heat up. Luck that the bed and hotend heat up as that sounds like the motherboard temperature sensors have also survived. If the motherboard fan port is dead, you might have to add new 24V fans and hook them directly to the 24V power supply to run 100% all the time...

vinny98

Yes my a5s and I have had our fair share of fights over the past 3 years but this time I think I really screwed things up between us lol...so if I replace the motherboard then I could still have speed control over the fans...or just go directly from the power supply and have no control? I would hate to replace the board if that is even a possibility, but it might be cheaper than buying a new machine because I make a lot of functional parts so 100% all the time probably isn't going to work for me. How would go about hooking up the fans to the power supply? if they come with connectors am I going to need to expose the bare wire and connect it to terminals on the power supply somehow? 

Samuel Pinches

I recommend to get a new replacement motherboard... I think that sounds like the best option in your case.

vinny98

Sam I have exciting news! I think....... I took the gantry off and went into the bottom end of the printer. It might sound weird but I just kind of sniffed around since I knew there would be a burnt smell from wherever the short happened. Turns out nothing happened to the main board/motherboard. I think I got extremely lucky here somehow. I will post photos but the name stamped on the pcb is "A3S Convert PCB V0.2" and I can see the scorched and split metal in the circuit. Is there a replacement for this somewhere? I will do some research and try to find it but if you know where I could purchase the part from that would be awesome!

Samuel Pinches

Oh wow.... I think that is good news? I hope? It is a custom board too, but I imagine it would be cheaper than the main motherboard. I think you would still need to contact jgaurora/jgmaker.

michalko99

or if you have multimeter and soldering iron, you can reroute traces by soldering thin wires wires directly. Then just insulate them to avoid possible contact with printer case and you are good.