Unfortunately not repairable. Failure modes: cathode melts, gap gets larger, unstable arc; anode melts or cracks, possible catastrophic failure; seals (uranium glass) to tungsten leak, xenon bleeds out; envelope fractures, catastrophic failure! In some cases electrodes vaporize and plate the inside of the envelope. Details at https://www.sqpuv.com/PDFs/TroubleshootingGuide.pdf