[Hallicrafters] Re: SX-100 MK2 info

[Ken Kaplan]

Tony,

I have an SX-100 serial no. 292477. The serial on the notch unit is 199004A and is 
identified as a Mark 2A. It has the later tuning knobs with the small chrome central disks. 
I don't have the extra tube you describe. I assume it is in the area between T2 and T5? 
Have you traced the circuitry to see what it does? The 6BY6 is usually used as a mixer. 
Did someone try to make this a triple conversion receiver? Maybe they wanted to 
connect to a Heathkit SB-620 only set up for 455khz. Any extra connectors in back? I'll 
try to control my imagination.

This is a very nice boatanchor. I use mine daily. Please update us on what you find out 
about this extra tube.

73 Ken kb7rgg

> well trying to get the last of my receivers restored before i start on my 
> transmitters.. pulled my working  SX -100 MK 2 out of the box and put on 
> the bench today.
> serial # 171639 and  Mark 2 serial  number on the  notch unit is  199719
> my question is i have both an SX 100 and  SX 100 MK 2 book but this radio 
> has an extra tube installed next to the 6bj7 det /anl/ave tube. it is a 
> 6by6  it is also connected to the  AM/CW SSB switch on the front..
>
> now the radio works fine i am just going to replace the caps and a bad rf 
> gain pot.. the only thing that makes me wonder if this is a factory mod 
> /upgrade or not is that the extra socket is mounted to the chassie with 
> screws and all the others are brads.
> of course it would be faster to use screws instead of brads if this was a 
> production change down the line after the chassie was punched and the 
> sockets added.
> was there a Mark 2A or a Mark 3 ?
> thanks
> 73 Tony
>
> QBE  ZUT  DE WA4JQS
>
> ANTHONY W. (Tony) DePrato WA4JQS