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40-190 What is this?
#5

I would suggest that you disconnect the added toilet paper roll antenna and then disconnect each lead of the original rotating loop antenna below and check for open circuits in one coil winding. The antenna coil can be repaired but you would have to unfasten the electrostatic outer shield covering to get at the coils inside. Most likely a wire has corroded apart at one of the fastening points inside. I repaired and restored a 40-201 and worked on the one in it. This electrostatically shielded antenna loop was only used in 1940 models. It helps eliminate noise interference from neon lights and motors that may have a spark jumping inside them. The antenna circuit of the 1940 models with this feature have a high impedance RF amplifier grid circuit. 1941 models changed to a low impedance loop and grid circuit in the RF amplifier stage to reduce noise.

Joe


Messages In This Thread
40-190 What is this? - by Edisla - 07-19-2015, 12:47 PM
RE: 40-190 What is this? - by morzh - 07-19-2015, 03:44 PM
RE: 40-190 What is this? - by Arran - 07-19-2015, 05:00 PM
RE: 40-190 What is this? - by DeckApe - 07-20-2015, 10:43 PM
RE: 40-190 What is this? - by Joeztech - 08-01-2015, 03:41 PM
RE: 40-190 What is this? - by Edisla - 08-02-2015, 01:01 PM
RE: 40-190 What is this? - by Edisla - 08-02-2015, 01:03 PM
RE: 40-190 What is this? - by DeckApe - 08-16-2015, 10:10 PM
RE: 40-190 What is this? - by Edisla - 10-07-2015, 09:36 PM
RE: 40-190 What is this? - by Edisla - 10-07-2015, 09:37 PM
RE: 40-190 What is this? - by Ron Ramirez - 10-07-2015, 09:43 PM



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