The lights will have a feed (either from a fuse via the light switch, or via the ignition switch, I'm not familiar with the thou but on my FZ6 they come on with ignition), and an earth on the bike's frame, a rusty / bad earth can cause high resistance which would cause dim lighting.
If there's any connector blocks / multi-plugs, make sure they're clean and tight as they can suffer with water ingress and corrode. Bear in mind wiring to clocks will naturally be routed near the headstock and can be affected by steering action.
Chances are you'll find damaged / poor wiring connections are causing the problem, rather than a fault with the circuit board itself - wiring is subjected to vibration / movement, chemical attack and temperature fluctuations (wiring routed near engine suffering constant heating / cooling).
If you have a multimeter, you can try testing for battery voltage (especially on your "dead" bulb holders, the contacts can weaken with time, and pcb tracks can break).
If its an "ordinary" circuit board, it should be repairable if you're handy with a soldering iron, if its one of those surface mount component boards they can be a bugger requiring specialist gear to re-make joints.
(Apologies if I'm "teaching Granny to suck eggs", but in my experience people often overlook basics when diagnosing electrical faults).
Topic: Circuit repair for clock bulbs? (Read 1220 times)
