[Boatanchors] Hammarlund Super Pro 150 question

[Al Klase]

Gang,

In light of the ensuing discussion, I took a look at my SP-110X. 
Unfortunately, it's not easy to get to the sensitivity pot.  So I made 
some measurements from the 3rd IF grid cap to ground with the switch in 
the "manual" position.

Sensitivity setting:

0    106K
1    174K
2    176K
3    176.5k
4    138K
5    124k
6    117K
7    114K
8    113k
9    111k
10   110k

So my SWAG (Silly Wild-Assed Guess) is that the sensitivity pot is about 
150K with an /_antilog taper._/

Circuit hot shots, please check this out.


50-100K linear would not be disaster.

73,
Al

On 4/12/2021 11:36 PM, Al Klase wrote:
> Wally,
>
> FWIW, the sensitivity control in the SP-200 is 50K per the manual.
>
> Al
>
> On 4/12/2021 7:06 PM, Wally Gibbons wrote:
>>   Greetings,
>> I'm overhauling a SP150 I got a few years ago. The sensitivity 
>> control is
>> bad. The resistor element is missing pieces. Therefore I can't 
>> measure the
>> end to end resistance of the original for a correct value.
>>
>> The schematic of the SP150 is apparently identical to the SP110 minus 
>> the
>> crystal filter. But the sensitivity control resistance is not called 
>> out in
>> the service data.
>>
>> Does anyone know the value for the sensitivity control?
>>
>> Thanks..
>>
>> Wally Gibbons, AF7FH
>> North Logan, Utah
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-- 
Al Klase - N3FRQ
Jersey City, NJ
http://www.skywaves.ar88.net