[Hammarlund] SP-600 HFO Alignment

[Bill Cromwell]

Hi,

I took some radio/tv classes for a while (once upon a time) and they 
taught bending the *outer* rotor plates to get tracking in the AA5 AM 
broadcast band receivers. I have seen radios with intentionally bent 
plates and there was no satisfaction there. Don't do it.

73,

Bill  KU8H

On 3/24/20 11:11 AM, k2cby at optonline.net wrote:
> I would repeat in boldface underlined Never bend the plates of the tuning
> capacitor! It is undoable and a death sentence so far as proper alignment is
> concerned.
> 
> That said, there are several points to consider in trying to match the HFO
> frequency to the tuning dial.
> 
> 1.	On the frequencies below 7.4 MHz (the 3 lower bands) be sure that
> the IF is actually centered at 455 kHz, and on the higher bands be sure that
> the IF is aligned at 3,955 kHz and the crystal oscillator is putting out
> 3,500.00 kHz.
> 2.	Be sure there isn't some non-factory "improvement" hanging off the
> wire that runs from the plastic feed-through at the front of the RF strip to
> the VFO-Crystal oscillator switch. That wire leads directly to the HF
> oscillator, and any stray capacitance to ground will foul up the frequency
> calibration at the high end.
> 3.	Without touching the oscillator coils, use the proper size steel
> screwdriver to "exercise" the air variable capacitors of the oscillator
> section for each band. Especially if the boat anchor has been sitting
> untouched for a couple of decades, the capacitor shafts will stiffen and you
> will either bend or break a plastic alignment tool.
> 
>   
> 
> Miles B. Anderson, K2CBY
> 16 Round Pond Lane
> Sag Harbor, New York 11963-3821
> Phone: (631) 725-4400
> FAX: (631) 725-2223
> 
> e-mail: k2cby at optimum.net
> 
>   
> 
> ______________________________________________________________
> Hammarlund mailing list
> Home: http://mailman.qth.net/mailman/listinfo/hammarlund
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Hammarlund at mailman.qth.net
> 
> List Administrator: Gary Harmon, K5JWK
> ** For Assistance: gharmon at idworld.net **
> 
> 
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> 

-- 
bark less - wag more