[Hallicrafters] SX-100 MarkII

[David C. Hallam]

Joe,

If you have the Mark II schematic from BAMA, I believe it is really for 
the Mark IIA because it has the circuit changes for the Mark IIA.  The 
circuit changes are slight and involve only the crystal oscillator.  
According to Bob Krassa  AC0JL, they are:

Further Changes from Mark 2 to Mark 2A:

IF changed from 50.5 to 50.75 kc
Calibrator changed to plug-in type and
  CR1 1N295 diode added between R80 and C109
  R77 changed to 220K

I have the original manual that came with my Mark II and it gives the IF 
as 50.50 KC.

David
KW4DH

On 1/2/2013 11:31 AM, Joe Balestrini wrote:
> David, I am also in the middle of trying to get life out of my SX-100 MARK 2  and my MARK 2 schematic shows the IF at 50.75.  I didn't think it was 50.75 only in the MK 2A.
>
> Joe
> KG6IMI
>    
> On Jan 2, 2013, at 8:16 AM, David C. Hallam wrote:
>
>> I am starting to refurbish a SX-100 Mark II.  Since there are no significant circuit changes between the SX-100 Mark II and the Mark IIA, is there any reason why the IF of the Mark II can not, or should not, be retuned from 50.50KC to 50.75KC of the Mark 2A.
>>
>> Some place I seem to remember reading the reason for the change. Can anyone tell me why?
>>
>> David
>> KW4DH
>>
>> -- 
>> A democratic government is the only one in which those who vote for a tax can escape the obligation to pay it.
>> Alexis de Tocqueville
>>
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-- 
A democratic government is the only one in which those who vote for a tax can escape the obligation to pay it.
Alexis de Tocqueville