Stealth Dimmer SP: Troubleshooting

Problem Solution
Screen goes blank or has weird lines on it when sync wire is connected Make sure you have an authentic Division 6 Stealth Dimmer. Some imitations have a completely different wiring scheme and could cause your GBA to malfunction if connected using the diagrams on this site.
The LCD frontlight starts flashing a few seconds after the GBA-SP is turned on This is an error code being generated by the built-in diagnostics. The number of flashes will tell you what to check:

1 Flash = A button shorted or connected incorrectly
2 Flashes = B button shorted or connected incorrectly
3 Flashes = Light button shorted or connected incorrectly
4 Flashes = SYNC wire not connected properly

Note: It is possible to have more than one error code.
One button seems to not work. For instance, the light can be made brighter but not darker Test the buttons using the built-in diagnostics. Turn the GBA-SP off, hold the button down, then turn it back on. Keep holding the button for 5 seconds. If the button is connected correctly, the error code that corresponds to that button should be blinked out on the light. Test all 3 buttons in this manner. If one of them does not produce an error code, check the wiring to this button.

1 Flash = A button held down
2 Flashes = B button held down
3 Flashes = Light button held down
The Light button turns the light on and off, but dimming doesn't work. Try holding the A or B button as you turn on the GBA-SP. If the light jumps to full-on (A) and full-off (B), then the chip is working. Check the wire that connects to the Light button (green wire, chip pin 2)
The chip is installed but appears to be totally dead Try the button test procedure listed above. If it works then you know that the chip is good and has power. If it doesn't work, double-check all your connections. Most Stealth Dimmer problems stem from soldering/connection issues.
The chip appears to be working, but its behavior is erratic or the controls don't work the way they are supposed to. Make sure you have an authentic Division 6 Stealth Dimmer. Imitation chips often have different connection requirements and won't function properly when connected using the diagrams on this site.
Dimming works fine, but the frontlight doesn't turn on/off when the Light button is pressed. Make sure that you have the SP version of the Stealth Dimmer. It is the only one that supports the on/off function of the Light button.