[Hammarlund] SP-600 setting up dials

[Richard Knoppow]

----- Original Message ----- 
From: "Richard Knoppow" <1oldlens1 at ix.netcom.com>
To: <hammarlund at mailman.qth.net>
Sent: Monday, January 30, 2012 10:26 AM
Subject: [Hammarlund] SP-600 setting up dials

    A note on the lamp dropping resistor. It should be about 
2 ohms. That will drop the voltage for the four No.47 lamps 
by about a volt which extend their lives by perhaps ten 
times. The dissipation is only about a half watt but I would 
use about a 2 watt resistor so it runs cool. The 
modification note for the IF gain control shows how to mount 
the resistor. Its not a difficult mod. the difference in 
lamp brightness can be seen only on direct comparison. In 
fact, I find the brightness of fresh No.47 lamps a little 
too bright.
    The best uniformity of illumination is a matter of 
diddling the lamp mountings and sometimes switching around 
the lamps where the filaments are not quite symmetrical. I 
always wondered why H didn't also illuminate the band 
indicator.



--
Richard Knoppow
Los Angeles
WB6KBL
dickburk at ix.netcom.com