Hi all, I have contacted Ameritron for support but we're still early into this situation. Just thought I'd ask here as well to get some other thoughts. I purchased a new Ameritron AL-811 from HRO a few days ago. Although I've been in amateur radio for 25 years, this is the first amp I've owned/used so it's going to be a learning experience. Anyway, I watched the MFJ videos online and read the manual instructions regarding tuning. The tuning process seems to be pretty straight forward. The issue is, on 20m, I noticed some erratic "flickers" in both the plate and grid current meters. Then, the plate began showing a constant reading of around 50 ma (unkeyed) and the grid went negative. I then contacted Ameritron. At this point, I didn't know the problem was only occuring on 20 so the tech had me check to make sure the tubes were all secure and had me to look beneath the tubes to see if these devices were illuminated (can't remember what he called them, but I think they are a type of spark protection). One is located beneath the tube on the left and the other is beneath the tube on the right, looking from the front. When the meters are erratic, the device on the right is flickering. When the unit goes into the positive plate/negative grid state, the device on the left is illuminated steadily. Any thoughts on what may be causing this? Again, it only presents itself on 20m. I haven't tried 30 yet but it does share the same band switch position. I would also mention that I can only get about 450 watts output on any band 160-40. I can understand this at 160 but I thought I should be getting close to 600 at 40. Any help would be appreciated.