[Hallicrafters] SX-17 Schematic Differences.

[rrkrr]

Bill,
There are early and late versions of the SX-17, and the SX-17 itself 
started out as a special mod to the SX-16 (added noise canceller circuit 
and 2nd RF stage for better image rejection) for a large order from the 
Gov't.  Early versions of the noise clipper used a 6J5.  In later 
versions this was changed to a 6H6 circuit.  In my SX-17, the 
detector/avc/1st audio tube is a 6R7 on the schematic, but there is a 
6SR7 installed (same tube except the grid terminal is moved from the top 
of the tube to a pin on the socket).  I don't know if this was done at 
the factory or not, but it seems to work fine. You can find documents 
that show many of these variations here (look toward the bottom of the 
page):

http://www.nostalgiaair.org/Resources/178/T0000178.htm

Bob
WB4TGG

Bill Gerhold wrote:

>I just noticed another big difference in my schematic vs the BAMA schematic.
>
>The BAMA schematic has a 6H6 tube labeled as a "Noise Silencer".  The
>schematic I am using says that tube should be a 6J5.  However, my receiver
>contains a 6H6 as indicated in the BAMA schematic.  The BAMA site say C69 is
>8uf.  My schematic says it is 1uf.  My radio has the 1uf in it.
>
>Another maddening thing is the SX-17 schematics do not show tube pin numbers
>or component values on the print unlike the halli schematics of the 50's and
>60's.  Thank GOD, I never threw out my old RCA Receiving Tube Manual or my
>RCA Transmitting Tube Manual.  Therefore, I have all sorts of conflicting
>information and need to refer to multiple pages of information to find one
>bit of information.
>
>Picture this; I have an upside down SX-17 on my bench. I am surrounded by
>(2) differing schematics taped to the wall.  Various photocopies of (2)
>differing parts lists.  One open RCA receiving tube book used to identify
>the tube elements and pin assignments.  Various tools, soldering iron, new
>parts etc and a battery operated blood pressure cuff.  Just wish my head
>rotated 360 degrees.  However, I am having fun.
>
>Thanks to everyone for your help and listening to me howl about these old
>radios and the apparent lack of accurate 67 year old information.  How could
>Bill Halligan do this to me.
>
>K2WH
>
>
>	
>
>______________________________________________________________
>Hallicrafters mailing list
>Home: http://mailman.qth.net/mailman/listinfo/hallicrafters
>Help: http://mailman.qth.net/mmfaq.html
>Post: mailto:Hallicrafters at mailman.qth.net
>----
>List Administrator: Duane Fischer, W8DBF **for assistance**
>dfischer at usol.com
>----
>Hallicrafters Collectors International: http://www.w9wze.org
>
>  
>