Both LED's should light up with similar brightness. They indicate that the circuit is complete and charging is taking place. They will not go out when charging is complete and are strickly a manual charger that must be monitored for charge time. If there is flickering of the light then the circuit is being broken somewhere it could be at the Tx plug but most often on those chargers it occurs where the wire go into the potted chargers (internally these chargers are not effectively repairable) however if you can isolate where the brake in the wire is then its simple to repair. Also carefully check the the plug receptical inside the Tx for spring contact pressure.

John