[Hammarlund] HQ-129x RF Amp. 6SS7 pin 3

[RJ Mattson]

Hi Ken
I think I found the answer.
A popular mod was replacing the 6SS7 RF amp with a 6SG7.
This mod only requires lifting pin 3 from ground on the RF stage socket.
Why tying pin 3 to pin 5 is a mystery since both are 6SG7 cathode 
connections.
Maybe it makes both tube types function in this circuit?

The HQ-129x Manual's diagnostic chart expects +3.2 vdc on the 6SS7 RF amp 
cathode at full sensitivity.

bob...w2ami

----- Original Message ----- 
From: "Kenneth G. Gordon" <kgordon2006 at verizon.net>


On 22 Jan 2007 at 20:34, RJ Mattson wrote:

> My HQ-129x schematic shows the suppressor grid (pin 3) of the 6SS7 RF
> amplifier should be tied to ground. On mine, pin 3 is connected to the
> cathode (pin 5). This makes the suppressor always positive.

How do you arrive at that conclusion? Have you measured the voltage?