How to repair a Savi's Workshop Lightsaber (Disney Star Wars Experience)
Published 2021-7-6Watch on YouTube: youtu.be/0F5pbxJ6WLI
I'm not even sure what to call this thing...
The Disney's Star Wars: Galaxy's Edge Savi's Workshop Handbuilt Build-Your-Own Lightsaber Experience™ Lightsaber Blade™... I guess?
Anyway, it appears to have been purposefully designed to break.
I can think of no other explanation.
Certainly no toy that you ever owned from the 70s - or even 90s - has parts of this sort that should theoretically last until the end of time and yet is this fragile.
What's inside
There are two circuit boards.
- The first is about 2.5 feet long and full of LEDs
- The second is about 2 inches long and has all of the controls
There's also a connector to the battery and several plastic pieces designed so that everything is held together and only fits in one direction.
How it breaks
The **** thing is only held together by 9 pads with a paper thin layer of solder.
It doesn't even have glue.
It's a miracle that they even survive shipping!
It's insane!
There's absolutely no way that it'll last through the types of actions that trigger the gyroscope for even a modest amount of time.
I can't see any reason to design the thing like this unless the intent is for it to break. Honestly.
Anyway, modest use will eventually cause get hairline cracks in the solder and then either segments or the whole thing will fail to light, or you lose colors.
Pinout
| Pin | Label | Function |
|---|---|---|
| 1 | B | Blue LED power |
| 2 | G | Green LED power |
| 3 | R | Red LED power |
| 4 | GP4 | Ground Pin 4, the blade's final (tip) segment |
| 5 | GP3 | Ground Pin 3, the blade's 3 segment |
| 6 | GP2 | Ground Pin 2, the blade's 2 segment |
| 7 | GP1 | Ground Pin 1, the blade's first (base) segment |
| - | - | - |
| 8 | GND2 | Ground 2 |
| 9 | GND3 | Ground 3 |
The ground pins are NOT common. They each control a different segment of the lightsaber blade - which is how it lights up, up and turns off down.
I'm not entirely clear on how it works, but I think there's two different voltages - one that drives the lights and another that controls the logic.
How to fix it
If your saber isn't broken in some way already, it's about to break.
Whether or not you can see it, the (less than) paper thin layer of solder between the 9 contacts has broken. That's why it doesn't light up in certain segments (or at all).
There are two fixes:
1. Fast & Temporary (will fail again)
- Wet, wick away, and remove the bad solder (I use Chem-wik, but goot wick + Flux will do as well)
- Re-tin the pads that touch each other with proper rosin-core lead solder (either 60/40 Kester or 63/37)
- You don't need the solder to ball up - just get it to reflow and it will stick
2. Tedious & Permanent
- First: Bond the two boards in place with generic 2-part epoxy (non-conductive)
- Make sure that the pads are aligned properly
- Try small (4-inch or 4.5-inch) trigger clamps, or maybe even sturdy clothes pins
- Solder magnet wire (I used 28awg) from each of the test points / pads to their corresponding partner on the other board
- Use a multimeter in continuity mode with pinpoint probes to make sure you got it all right
Reassembly Pro Tips
- The smaller plastic cylinder halves go back on first
- it should only fit easily one way
- you may need to move the magnet wire a little so that it passes where there's extra room
- The plastic blade goes on next and aligns on a few obvious notches
- Put the two silver notches into the outer half-cylinders
- one is bigger than the other, for alignment
- Align the battery connector to the outer half-cylinder
- there's an orienting notch
- Screw each of the 3 screws 90%, then go the last 10%
Troubleshooting
It doesn't work at all
Probably GND2 or GND3 is disconnected
One or more of the colors doesn't light up
B, G, or R is disconnected
One or more of the segments doesn't light up
GP4, GP3, GP2, or GP1 is not connected (refer to the table above)
The Secret Manual
After I had done all this, my buddy showed me this:
That will come in handy if you want to do some other hacking of the hardware, or creating your own software/firmware for a custom controller.
How it should have been
There are several ways this could have not been a problem.
- The entire circuit could be just one board
- Connect with plain old wires, and secure with plastic spacers
- Pins on one board and holes in the other (Blue Pill / RPi Zero style)
- A socket (like an m2 ssd)
- A connector cable
- A ribbon cable
This is a $200 lightsaber. The additional cost, if any, of those solutions is between pennies and a dollar.
Again, there are so many sane solutions that could have worked perfectly for the lifetime of the silicon, or a few generations of human - or at least until it was broken in the traditional sense of excessive force.
This truly seems to be designed intentionally in the most fragile way possible as a way of ensuring that its natural use would be its demise.
By AJ ONeal
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