Your Super 73 is completely dead - here is the exact order to check every possible cause before assuming the worst.
Push the power button and nothing happens. Before you panic, work these six checks in order. Most Super 73s that "will not turn on" are back on the road in under 30 minutes.
A fully depleted pack drops below the wake-up threshold. Plug in for 15 minutes, then try again.
Super 73 batteries need to click into the frame lock. If it is slightly off, the contacts do not touch. Pull the battery, reinsert, feel for the click, listen for the beep.
On models with a key, the switch itself wears out. Wiggle the key in the switch. If the bike flickers to life, the key switch is bad. A replacement runs $15 to $25.
Salt air corrodes the male pins on the battery and the female contacts in the frame. Look for green or white crust. A quick clean with contact cleaner and a nylon brush usually restores contact.
If the bike wakes up with a different pack, the original battery is the problem. Time for a battery health diagnostic.
Inside the battery pack there is a main fuse. If it blew (usually from a short or an over-current event), the pack looks dead but the cells are fine. Replacing the fuse is a $30 job.
If none of the above brings your Super 73 back to life, book a mobile visit. We carry backup batteries for on-site swap testing so we can diagnose in one visit whether the pack, the controller, or the wiring is at fault. Call (858) 683-6900.
Coastline Fix is North County San Diego's mobile eBike mechanic. We come to you - same-day or next-day.