Zivan USA in CA has factory repair service. I have used them three times on three different GEMs. All three 18 year old chargers have proven durable and are still in daily use. If you are handy with electronics and soldering, the correct fuses are available and appear at the link below:
Otherwise, the charger can be sent out for repair. There was also a firmware update years ago. The charger will say “micro upgraded” if the upgrade has been performed.