Jdoshi..it is possible that your tubes are tired and need to be replaced. I've seen instances where a tube may arc after 1500 hrs. It happens. My suggestion is to replace the tubes. It beats having a tube arc over on you and having to have someone like me replace the resistors and check that all the voltages are okay. If your Ref210's have lost that lovin' feeling, it's time. When the tubes are new I put my tube tester measurement numbers on the tubes. When it comes back in I test them again to see how much the tubes have lost. I don't know if you will also need to replace the front end tubes and drivers. I would consult your owners manual for that info. ARC is mad crazy right now. I just ordered VTM200 tube sets for my customer whose amps I just repaired. I hope they can ship to me tomorrow. Be advised that unless you sent your Ref210's back to ARC for the KT 120 update, you can only use the 6550WE's. They no longer have Winged "C" output tubes as the factory burned down. The 6550WE's are excellent sounding tubes.
