My Kronan is a simple bike with simple "extras", the headlamp is a filament bulb powered a dynamo, a simple LED tail light and a Kronan bycicle bell.
Since I installed the front cargo fork I had to reroute the power from the dynamo to the alternative location of the headlamp (on the other fork arm).
I noticed that there is a light sensor and when I leave the bike in a shed or I stop the tail light turns off after some time. But my current problem is that sometimes during a long route the light turns permanently off. I had to open the box and see!!
Apparently there's a transistor, a light sensor (top, back of the PCB), a red LED (transparent), a capacitor (bottom, back of the PCB) and an embedded IC. The IC has a blob of plastic (next to the capacitor) over it so no chance of knowing what it is. My current possible culprits are:
the battery connection that has oxidized or the light sensor is not correctly placed and the sensor is influenced by the LED.
Currently I just opened the box, cleaned the contacts and straightened the sensor but I doubt that was the last time I had this problem.
I also had some time so I decided to check if I had any noticeable chain stretch, I folded a new one over the current one while breaking and checked for any big difference after 10 links... so far, everything looks similar (i.e. no noticeable stretch).
I found more sites (here, here, and even in Wikipedia) giving instructions on how to check for chain stretch.
2 weeks ago