Do both tubes show the same degree of orange? Is this when keyed but with no drive?

What is the idle plate current, with the Eimac tubes, then the other tubes?

Gary

W0DVN

On Mar 21, 2024, at 12:07?PM, Paul Kraemer <elespe@...> wrote:

Jim

I have two L7, one bonded grids and other stock.? The bonded grids makes more power than stock.? It is the stock one I need to have OK as it is sold waiting to be picked up.? I just want it right, stock condition,? and not another project.

I have a 2kv hipot tester so not really high @ only 2kv

All testing done in SSB mode, 89 watts drive from TT OMNI VI+, L7 output a KW more or less depending on band

As earlier comment the import tubes? showed orange plates and not the typical faint orange like all do under normal conditions but I mean LOTS OF ORANGE and the Eimac don't do that.? Baffles my simple mind as it was working perfectly for years and then I sold it and was just going to tweak the meter adjustments before it left and before I even got to that it started it's bad behavior.

In the future if I needed more tubes I WOULD without hesitation try what RF Parts offers today.? Their reputation and good service has earned that but I'd just like to know what went off the rails with the pair in a working amp.

Paul K0UYA

On 3/21/2024 5:26 AM, Jim VE7RF wrote:

Paul, I assume you have the grids directly bonded to the chassis ?? ? That alone will improve stability.? I would leave the suppressors alone.?

Do you have a hi-pot tester ?? ?One / both tubes could have lost some of their vacuum.? ?But if it arced from anode to grid, it shoulda just taken out a fuse... and not the tune cap.?

Did it arc in the CW (1900v) position..... or in the SSB ( 2650 v ) position ??

Ok, this is where my hb adjustable spark gap pays off.? ?One across the tune cap...protects the tune cap and the bandswitch.? ?2nd one is across the load cap.?

Usually what happens is when plates arc, they are a bitch to get cleaned up, depending on damage.??