[Hammarlund] SP-600 alignment

[Richard Knoppow]

    I suspect it is a mechanical alignment problem with the 
tuning capacitor. There are two sections, on the single 
conversion bands both sections are in parallel, on the double 
conversion bands they are in series. Take the cover off the RF 
compartment and look to see if the outer leaves of the oscillator 
capacitor have been bent. If not you are ok. Its possible that 
the stators are not centered in the rotors. To really check this 
you have to remove the capacitor. Not difficult to do but a lot 
of work. Once out you can inspect it to see if the stators have 
wandered from their center position. If they have you can fix it 
by loosening the clamp screws and using feeler blades to get it 
centered. Must also be centered up and down, that is the edges of 
the rotor and stator should be on the same plane. Can fix that 
with a small straight edge.
    If someone has bent the rotor blades you can try 
straightening them. I found this very difficult but if a 
replacement is not available its worth trying.
    Again, if there is a mechanical error it will show up on all 
bands, not just one or two. Because of the difference in 
connection between single and double conversion the error may 
show up more on one than the other.
    In any case you should be able to see if there is a gross 
error in centering or if blades have been bent by removing the 
cover from the RF.

On 11/11/2019 2:42 PM, wb3fau55 at neo.rr.com wrote:
> Folks, i have an older SP-600 here i am trying to do tracking
> alignment. i have it working well on the lower 3 bands-[single
> conversion] . On 7.4 to 14mc, the tracking is too wide- about 300 kc
> at top end. On 14 to 29mc, the is an error of 900 kc, which i cannot
> narrow. is the error in the 2nd conversion or bad parts in 6C4 osc?
> thanks for any advice Russ wb3fau.
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-- 
Richard Knoppow
1oldlens1 at ix.netcom.com
WB6KBL