[Boatanchors] [BoatAnchors] Refurb S-38C Gone Crazy

[Bob Jackson]

Thanks, all. 

First, parts and schematic don't match - different "runs" as someone suggested.
Secondly, vol.pot doesn't look original and tests (using vtvm) look like linear taper.
Thirdly, vol.pot is only 500K. Non-matching schematic calls for 2Meg.

Ordered some audio 2M audio pots and will go from there while re-heating all solder joints in that part of circuit.
Thanks to all for the help!

73,

Bob  AG5X
  ----- Original Message ----- 
  From: Scott Robinson 
  To: Bob Jackson ; porch ; qth 
  Sent: Tuesday, April 01, 2014 12:43 PM
  Subject: Re: [BoatAnchors] Refurb S-38C Gone Crazy


  H Bob,

  Check the resistance of the volume control wiper to ground at its lowest 
  setting. Also verify all grounds (solder bon dthe rivets to the chassis) 
  hear the 12SQ7.

  /scott

  On 4/1/14 9:03 AM, Bob Jackson wrote:
  > This radio won't go silent, not even close! When turned on and warmed up, a low but fully "listenable" level of clean audio is present. With only slight advance of the volume control, audio level skyrockets. The set is fully re-capped; all caps and resistors test OK. Volume pot is good.
  >
  > Circuit has been traced multiple times for voltage values. All are within bounds of schematic values. Swapping out the 12SG7 for a 12SK7 is of little help. 12SQ7 has been swapped as well - no effect. Has anyone else had this problem? Any suggestions would be very welcome.
  >