Shutdown amtetcher SNF 2008-02-16 15:02:14: 2 of the six panels have burnt and melted at the top

When i came to use AMT, the machine had stopped running process 2 saying DC values were out of range. So i opened the bell jar and looked at the panels and panel 4 & 5 (of the 6 panels) had burnt and melted at the top and fused with the top with the hexode (most likely due to arcing). Have shut down the machine.