{Collins} More on the 30S-1 saga

It sure is nice to have multiple amps to test with and against.
First off I have a known good working amp that I will call the Good one!
Second I have the amp that I am working on, I will call the Second amp.  It
is the one that all of my recent questions have been about, I found the
SSB/CW switch miss wired... repaired.  And then thought I had a tube with a
leaky grid, and a second tube with excessive screen current.

Well, I took both of the suspect flaky tubes and put them one at a time
into the known good amp and they both work flawlessly producing approx 1200
watt PEP output into a dummy load with approx 65 watts drive.  I believe
that these two 4cx1000a tubes are good.  No sign of grid current leaking on
the one, and at 1000 watts steady carrier (3 seconds on, 15 seconds off)
they both show no grid current and approx negative 5ma screen current.
These are almost identical readings that I get when I stick the NEW
4CX1500b tube in the amp.

I feel much better now that I know the tubes are okay... so this all points
back to the second amp still having an issue.

So here is the question.  What do I check next on the Second amp?  I put
the 4CX1500b in the second amp and it indicated the excessive screen
current just like one of the 4CX1000a tubes.  What should I check next.

Again I have the fortune of having a know Good amp that I can make
comparison readings on, just not sure which direction to go right now.

Thanks again Greg WQ0P

Oh yeah, We have not even started on amp #3 yet!!!

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