General Electric E-86
   

1936
click on image to enlarge



For a brief moment in the mid 1930s, GE arguably led the field of radio manufacturers in terms of technological advancement and of the quality of both design and build of its sets.
 

Tube Complement
RF amplifier 
 1 
 6K7
 converter 1 6A8
 IF amplifier
 2 6K7
 detector/AVC 1 6H6
 audio amplifier
 1 6F5
 audio output
 1 6L6
 B+ rectifier
 1 5Z4

 

It's hard to say how long this radio remained in service to the original owner, but three of the four original electrolytic capacitors had been replaced as had the original line cord--with a three wire cord with moulded grounding plug.  Hmm.

Other than those repairs and a partially bypassed candohm ( Undecided ) everything under the chassis was frozen in time.  Actually, petrified might be a better word, as 75 years of dessication had taken its toll on the rubber hookup wire.  In a quick powerup the radio was still very much operational, proving it was a worthy candidate for restoration.





I made a foolish error when building up the candohm replacement.  Perhaps as a combined result of the distracting use of the roman numeral "M" to denote thousands in the schematic and the drive to finish the task in defiance of the need to rest at the end of an all-night session, I managed to put 1.2K and 1.5K in place of 12K and 15K sections respectively.  It was terribly discouraging to power up the radio after checking all the connections against the schematic, only to be greeted with badly distorted audio and then, with what can only be described as the radio letting out a painful shriek, no audio. 

Surprisingly, the B+ current had only increased by about 20 ma from the reading taken before recap, so that alone wasn't a red flag. Fortunately I made mention of the candohm replacement when I sought some guidance at the Antique Radio Forum.  Once the proper resistance values were placed in the voltage divider, the audio section once again worked perfectly.





The original speaker had several severe tears in the cone.  For minor tears I have found that nail polish works well, but for this speaker I also used coffee filters for added strength and to close space where original cone material was missing entirely.  It sounds much better than it looks!




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