[Amps] Triode bias issue

[Glen Zook]

Is the capacitor between the r.f. input and the cathode of the GI-7b tubes shorted or missing?
 
Glen, K9STH


Website:  http://k9sth.com


________________________________
 From: Wilt Barnum <w1ipl.me at gmail.com>
To: amps at contesting.com 
Sent: Wednesday, April 3, 2013 6:56 AM
Subject: [Amps] Triode bias issue
 
Hello all,

I have just finished an HF table top medium power amp using 2X GI 7Bs. In
particular the bias circuit works perfectly drawing the proper idling
current. UNTIL the rf cables are connected i.e input and output, then the
plate volts drop some ( abt 100volts) and the tubes no longer draw idling
current. No malfunction of the HV  supply is apparent and it works fine
with another pair of GI7bs for 6M.

What am I missing?