The BFO/carrier oscillator crystals may have aged and the 15.3 MHz
oscillator (L4) which centers the passband tuning may need adjustment.
This you can do by ear, but the BFO frequencies require the use of a
frequency counter.
73,
Bob WB2VUF
On 1/1/2011 2:41 PM, Dr. Gerald N. Johnson wrote:
> Miniature electrolytics are ripe for replacement due to old age. Go for
> low ESR high temperature rated for the best performance and long life.
> Don't forget those on the display board. I doubt Tentec would consider
> shotgun replacement of electrolytics to be practical at their costs of
> labor.
>
> As for alignment, if it hears antenna noise louder than its noise on all
> bands and puts out rated power everywhere, I don't think it needs
> alignment. I've never found alignment a better procedure than proper
> signal tracing for troubleshooting and problems. Indeed alignment can
> introduce more problems from adjusting parts that didn't need adjusting
> but were frozen with age. Split cores come to mind, NEVER use a metal
> allen wrench on a core of a coil. It gets a thousand times harder to
> turn after its split by the metal wrench. Use only plastic alignment
> tools that fit the cores. Alignment was needed more in tube radios where
> tube replacement was commonly required and the tube capacitances were a
> significant portion of the resonann circuit tuning C. Then a different
> tube with 1 pf different C required alignment. We aren't swapping
> transistors that much, though when a transistor is replaced and its
> connected to tuned circuits, alignment of that stage is most appropriate.
>
> 73, Jerry, K0CQ
>
> On 1/1/2011 12:21 PM, Andrew Moore wrote:
>> I've got the Corsair II on the bench for a PTO cleaning or possible rebuild.
>>
>> While I'm at it, I'm considering
>>
>> a) complete realignment
>>
>> b) replace any components that may go out of spec due to age
>> (would electrolytic caps fall into that category?)
>>
>> I realize there's also a "don't fix it if it ain't broke" angle but I'm
>> leaning towards realignment/replacement.
>>
>> Seeking opinions on a) and b) above.
>>
>> I don't have a scope, but do have a multimeter, wideband noise generator,
>> and test oscillator for 20/40/80 meters. Better off sending it to Ten-Tec
>> (if they still do this), or do it myself?
>>
>> Who's "been there done that?"
>>
>> Thanks,
>> --Andrew, NV1B
>> ..
>>
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