Our Stationary bike stopped working suddenly. One day it just failed to light up when it was pedaled. I let it sit for several weeks before doing anything about it - I wasn't sure where to start.
Finally, I started searching for posts like this one, but I found no accounts of owners' experiences in troubleshooting and repairing Cybex 500C upright bikes. I did find sites that sold repair parts, though. All of these sites offered a replacement sealed lead acid battery. This seemed like a likely candidate for an electrical failure, especially since one site indicated that you could expect an 8-year useful life from these batteries, and my bike was 11 years old.
I didn't think my bike had a battery, though. It started generating electricity when you pedaled, and it shut down when you stopped pedaling, so why would it need a battery?(I guess it must help to smooth out the variable flow of electricity that comes from pedaling). Anyway, I removed the side cover from my bike and did in fact see a battery such as the one pictured on the parts sites.
I found the battery available for about $26 -$66 dollars plus shipping at various sites, but I wasn't sure if these replacement batteries were the same quality as the original. After removing my battery, I found a manufacturer's name and model number: Hawker Energy 0819-0012.
When I searched for that, I found the battery available from an Amazon affiliate for $21 ($27.65 with shipping). I ordered it on a Sunday night and received it the following Friday.
It took less than an hour to remove and replace the battery, and the bike worked fine afterward. The shop where I bought the bike wanted $150 plus parts to come out to my house and repair the bike, so I figure I saved $150 plus whatever markup they would have charged on the battery itself.
Removing the right side panel:
1. Insert a small screwdriver and pry up under both sides of seat-post boot to release the 2 small clips that connect it to the side panels.
2. Remove 9 Philips-head screws from right side panel.
3. Align right pedal with seat-post and gently work the panel to slide it upward in the direction of the seat-post until it clears the pedal. (This may take a few tries).
Removing the Battery:
4. Remove the wires from the battery terminals. (Be careful when replacing these wires on the new battery as the terminals seem to bend easily).
5. Remove the 2 nuts and screws that hold the battery to the frame. You will need to find a Phillips-head screwdriver that you can fit in to the limited space, as the screw will turn when you try to loosen the nut. Be careful not to damage the circuit board while turning the back nut.