[Hallicrafters] S-38 Question

[Richard Knoppow]

----- Original Message ----- 
From: "Gary" <xfrmrs at roadrunner.com>
To: "List Hallicrafters" <hallicrafters at mailman.qth.net>
Sent: Saturday, March 23, 2013 2:00 PM
Subject: [Hallicrafters] S-38 Question


>A friend brought over an S-38 with all the tubes pulled out 
>and does not know where they go. For the life of me, I can 
>not find anything on the internet that will tell me where 
>they go. I have checked several websites but no tube 
>layout. I know, I could figure it out from the schematic 
>but thought this mite be quicker.
> Any help will be appreciated. This is the S-38 that uses 6 
> tubes.
> Regards,
> Gary

     If you do any work on this set beware that one side of 
the line is connected to the chassis.  The chassis is 
isolated from the cabinet by insulators but, with time, they 
begin to break down.  Check to see that the cabinet and 
chassis are not connected together and also its a good idea 
to make sure the chassis side goes to power line ground (or 
neutral).  Its very likely the filter cap has gone bad with 
age.  Replacement caps are available from a couple of places 
but since its under the chassis one can just mount plain 
radial lead ones there. Its also likely the paper caps are 
leaky, again from age. New plastic film caps are easily 
available.  With new caps the set should perform quite well. 
Note that the dial lamp is run from a tap on the rectifier 
tube filament and gets a jolt when the set is turned on. The 
bright flash is normal but seriously shortens the life of 
the lamp.  I think you can get a varistor to go across the 
lamp to keep this from happening.  Also, the polarity of the 
line makes a difference in the residual hum so very often 
reversing the plug will reduce the hum, but again, 
regardless of the hum avoid connecting it so that the hot 
side goes to the chassis.  This is a problem with _all_ 
AC/DC sets because they could not have transformers.
     FWIW, DC current was supplied to some parts of the U.S. 
notably some parts of Manhattan, until perhaps twenty years 
ago.


--
Richard Knoppow
Los Angeles
WB6KBL
dickburk at ix.netcom.com