Question 1

Why won't my Raspberry Pi turn on in my arcade cabinet?

Accepted Answer

Check that the USB-C adapter is plugged in, the UPSPack ON/OFF switch is ON, and the LiPo battery is connected to the JST port. Try a different USB-C cable — some are charge-only with thin conductors. If the battery is fully depleted, charge for 10+ minutes before switching on.

Question 2

Why does my Raspberry Pi show a lightning bolt undervoltage warning?

Accepted Answer

The power supply can't deliver enough current. Use a 5V 3A adapter for Pi 4 or 5V 5A for Pi 5. Use a short, thick (20AWG, under 30cm) USB-A to USB-C cable between the UPSPack and Pi. Remove unnecessary USB devices or power them from a separate hub.

Question 3

My arcade button doesn't register when I press it — how do I fix it?

Accepted Answer

Verify you wired to the NO (Normally Open) terminal, not NC. Check that the COM terminal is connected to a Pi GND pin. Test continuity with a multimeter. Ensure internal pull-up resistors are enabled in your config. Try a different GPIO pin to rule out a dead pin.

Question 4

Why is my arcade button always pressed / stuck on?

Accepted Answer

You likely wired to the NC (Normally Closed) terminal instead of NO. Move the signal wire to the NO tab. Also check for shorted wires, bare wire touching the cabinet frame, or a stuck microswitch lever.

Question 5

How do I fix buzzing or humming from my arcade cabinet speakers?

Accepted Answer

Install 600:600 Ohm 1:1 audio isolation transformers between the amplifier output and speakers to eliminate ground loop hum. Keep audio wiring away from GPIO signal wires. Use a dedicated power source for the amp rather than sharing with the Pi.

Question 6

My joystick directions are reversed or swapped — what went wrong?

Accepted Answer

The joystick gate may be rotated 90° or 180°. Remove the bottom plate, rotate the gate, and re-test. If using a 5-pin harness, verify the pin order matches your GPIO mapping. Label wires with colored tape (U/D/L/R) before connecting.

WIRING TROUBLESHOOTING