Replace Power Button on the BIQU Magician 3D Printer

This IBLE describes the steps that I followed to replace the push button style power switch on the BIQU Magician 3D printer.

It is possible that this might be an odd situation where the printer stopped working as a result of a bad switch, but I'm hoping that this IBLE helps others who face a similar situation with the BIQU Magician 3D printer.

1. The Coolais 16mm Latching Push Button Switch with Blue LED Light rated at 5A 12V - I got this pair from Amazon
2. Suitable Hex screw driver to open/close up the BIQU service panel cover
3. Solder Iron
4. Helping Hands

OPTIONAL: These depend on the kinds of issues you may see once you open up the 3D printer to replace the button

• Needle nose pliers
• Scissors
• Shrink tubing

NOTE:

• The push button must be of the Latching type and not momentary!
• Meaning, one push the switch turns ON and remains ON, and another push the switch turns OFF
• These switches come in pairs - which I think is good because you would need a spare as you will see shortly
• You don't need the extension harness that come with the switches as part of the package

Background

Several years ago, I had bought the BIQU Magician 3D printer and published an IBLE that you can read here.

Since then the Printer has served me pretty well. Being a Delta Robot, the printer can turn out accurate parts at high speeds when compared to conventional Cartesian style printers.

In my case the BIQU shines especially when delivering accurate circular parts when printing at the regular 0.2mm layer height. The replaceable inserts for my 3D printed drill storage box came out excellent with the right tolerances!

The Problem & Symptoms

About a couple of years back, the printer started shutting down abruptly. There was no pattern or method to this craziness. The symptoms exhibited by the printer were as follows:

1. Printer would turn on and shut off midway when heating up
2. Printer would turn off abruptly midway or even towards the end of a print
3. The size of the print did not matter - small prints that would take less than 30 minutes wouldn't finish
4. There was no loss of temperature or any uncontrollable rise in temperature anytime during these incidents

Getting in touch with BIQU did not yield much insight. Per their response, they suspected that the heating element was damaged. I opened up the print head at least a couple of times (when I found the time to do it), but there was nothing that revealed to me that the heating element or the temperature sensor was damaged.

Besides, there was no thermal runaway problem, and some prints really did complete without incident.

On the other end, looking inside the service cabinet did not reveal any loose or broken wires.

However, I noticed that it was getting harder for me to turn on the printer and keep it on. Eventually. when I pressed the push button, the printer would not turn on.

This made me suspect that the switch might be the cause of the problem!

There was no identification marking on the BIQU OEM Switch accept the terminals marked on the switch. Based on this info, I decided to order the The Coolais 16mm Latching Push Button Switch with Blue LED Light rated at 5A 12V from Amazon. Sadly, I did not find a replacement switch on the BIQU website.

First thing to do was to take note of the wires in relation to the terminals on the OEM switch.

Once I received the new switch, I marked 3 distinct terminals that were wired to the OEM switch.

Terminal C - goes to the Red Wire of the 3D printer

Terminal WY*Y - goes to a pair of Red-Black wires crimped to a common connector in the printer circuit

Terminal NO - goes to the Black wire of the 3D printer

Terminal NO is shorted using solder to the terminal that is physically connected to the Black wire

This is the step where you need to exercise the most care!

First, make sure that the terminals are correctly marked and you have identified the terminals that you need to solder.

Second, the solder has to be applied at the base of the terminals because the top of the terminal will need to be free of solder so that the printer wire can be plugged in to this terminal. At the same time, the hot solder iron can damage the plastic housing of the switch - one reason why getting a pair of these switches is a good idea just in case the first switch is damaged!

Finally, keep the switch stable using the Helping Hands or by some other means so that it doesn't move when solder is applied

1. I took a long solder wire, bent it to the shape of an "L" and then applied the solder iron with the wire held slightly above the base of the terminal
2. The solder would flow down and create a blob at the bottom of the terminal
3. I repeated the process to create a similar blob at the bottom of the second terminal
4. Finally, I applied heat to one of the blobs and gently dragged it with the tip of the solder iron towards the other blob to form the connection
5. All this time, I kept the solder iron away from contacting the plastic body of the switch

I hooked up the switch temporarily to the wires as shown in the picture. As seen in the pictures the terminals of the switch have been marked in Red, Black and Red Black colors to match with the wires that are connected to.

And luckily, the printer turned on and did not shut down as it did before!

The LED on the switch is also illuminated as it used to on the OEM switch.

Basic Testing

I kept the printer powered on for sometime and performed a few basic tests a couple of times:

1. Preheat PLA
2. Home Printer
3. Cool Down Nozzle
4. Turn Off Printer

So far so good!

But then I saw a few things that I really did not like and thought that I have to fix them.

These issues may not apply to you, but I have listed the ones I ran into nevertheless.

Partially Exposed Wiring

• The Red-White wires crimped on to the single connector had wire exposed
• When the switch is installed back on the printer, I felt this wire is way too close to one of the Stepper motors
• I applied a common sense approach to the wiring and covered the exposed section with shrink tubing

Untrimmed Protective Boots on Connectors

• At least one connector had a protective boot that was extending beyond the business edge of the connector
• When I unmounted the OEM switch, this connector simply slipped off because the overextended boot was simply jammed up against the back of the switch
• I trimmed the boot to size and this time, the connector did not tend to push itself out when connected to the new switch

Loose Grip Connectors

• The second issue with the connectors was that they were much too slack for comfort
• Pull them out of the switch a couple of times, and their grip would loosen completely when plugged back into the switch
• A gentle crimp on the connectors with a pair of needle nose pliers will do the trick of making them fit tightly to the terminals of the switch

I leveled the printer bed and managed to get a small, unfinished print out of it. A small amount of filament was still stuck in the extruder when the printer had shut down on me on my last attempt (before replacing the switch).

At least now, it was able to run without shutting down for nearly 15 minutes.

The video shows the printer in action after the power button was fixed. For nearly 6 hours now, the printer has been printing parts for the Second Stage of the SpaceX Falcon Heavy Rocket that I purchased from Fab365.

These parts need to be printed with 0.1mm layer height, and the BIQU sure did not disappoint!

Thank you for reading this IBLE and Happy Making!