Something's broken

Find your symptom, then follow the link to the fix.

Some fixes link to the L2 page

Anything about power, cabling or leader arms is written for the Nori L2. On an A3, use it as background only and get in touch.

Symptom	Likely cause	Go to
Session stuck at connecting, never reaches connected	Strict network — needs a TURN relay	Remote
Connected, but no video	Room mismatch, or the encoder is paused	Remote
Video is low-res / low-fps	Working as intended — it's the robot's power budget	Cameras
Camera fps falls off over a long session	Thermal throttling, not power. Needs cooling	Cameras
A camera vanishes mid-session	USB current cap on the Pi	Power
App can't see a leader arm	Charge-only cable, or a hub swallowing it	Leader arms
An arm moves the wrong joint / wrong direction	Motor IDs, or stale calibration	Leader arms
"Enter VR" is disabled	Not a secure context (needs HTTPS)	VR
No audio after joining a call	Autoplay policy, or the robot-side consent prompt	Audio
Robot's speaker disconnects mid-clip	Brownout — the clip was too loud	Power
One joint stopped, the rest still work	A stall. Working as designed	Safety states
Everything stopped and won't restart	Something is latched — E-STOP, or motor protection	Safety states
The robot latched itself, nobody touched it	Over-temp or over-current motor protection	Safety states
A joint went limp and won't re-engage	Its torque was cut to save the motor. Needs reset_latch	Safety states
A motor shows red or amber in the app	Hardware fault vs. not answering the bus — different fixes	Safety states
The computer is on but every motor is dead	The physical E-stop is engaged	Safety states
Desktop app opens to a blank window	Backend didn't come up on :8000	Install

Before you dig in

Three checks that resolve a large share of reports:

Is the robot actually reporting safety: ok? A robot in safe_hold or latched isn't broken — it's refusing to move on purpose, and it'll tell you why. Safety states.

Is it a power problem wearing a software costume? Cameras that vanish, speakers that disconnect, arms that stop responding — these are frequently the Pi's USB rail running out of current, not a bug. Brownouts and throttling.

Is it the cable? A charge-only USB cable is physically identical to a data cable and is the single most common cause of "the app can't see my arm."

Physically broken?

If a part snapped rather than misbehaved, check printable parts — for a growing set of A3 parts you can download the file and print a replacement yourself.

Still stuck?

Getting help — what to send us so we can actually diagnose it.