[Hammarlund] sp600 frequency question

[Eugene Hertz]

hello all,  

I have never aligned a radio in my life, but as soon as my RF generator arrives in the mail I might take on the sp600-jx26.  Here's whats up.

I noticed that the dial was off when tuning to wwv 15Mhz (I think the log scale read 25 instead of 0 that I guess I would expect) so I connected a frequency counter (actually tried two different counters) to the HFO 6C4 on the grid pin with a 5pf cap to remove the dc.

What I noticed on both freq counters was when I received the *strongest* signal both in sound and in s-meter the freq counter was off (in other words, one would expect the counter to show 15Mhz+3.955Mhz IF or 18.955Mhz. In actuality it read something like (didnt write it down but you'll get the idea) 18.990 or about 30kHz off. I dont actually remember how much off, could have been 5khz or something. I'll check again if it is material to the discussion.

So what does this mean? Does it mean the center of the bandpass for the if filter is off somehow? meaning I get a loud signal somewhere off the center? Or could it be the 5pf coupling cap that is throwing off the freq counters?  Could the dial being off be somehow involved with this?

Should I stop with this foolishness and just start a realignment process? (by the way, how hard is it? I have yet to read the process in the manual-not even sure if the process is in the manual! I can use a freq counter, o'scope and (once it arrives) an rf generator.  How many days should I plan for this? I have some black beauties but if I can avoid it, I would rather not touch them for fear of causing more damage. The radio seems to work rather well at the moment, just perhaps slightly off on frequency.

thanks!
Eugene