Hi Jim. I would be suggest not running positive screen voltage without the
plate voltage present. The screen could possibly be ruined by drawing excess
current. Someone please correct me if I am off base here.
Russ
________________________________
From: Jim Barber <audioguy@q.com>
To: "Amps@contesting.com" <Amps@contesting.com>
Sent: Sunday, March 11, 2012 10:47 PM
Subject: [Amps] Gettering GU-74B's in-place with screen voltage?
Is there any reason I shouldn't getter a set of GU-74B's in-place in the
amp with blower air, filaments hot, and with grid and screen bias
applied, but with the plate caps lifted? The amp in question is a QRO
HF2500DX that appears to be virtually unused, but also appears to have
been stored for an unknown amount of time.
Most of my experience is with metal-ceramic triodes (which "bang" after
storage without gettering) and good-old beam pentodes like the 813,
which don't, or at least haven't yet for me, at least. These (Russian)
metal-ceramic tetrodes are undiscovered country, so I may be being
over-cautious. Or not?
Thanks,
Jim N7CXI
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