[Boatanchors] EF Johnson thunderbolt

[KA2PTE]

Another question I have is regarding T103 the filament and screen supply 
xfmr.
Its apparently got taps for 110V and 120V and 110V was more common in those 
days,
and its been sugguested to make use of the 120V option as it sould mean less 
humm from the chassis.

T103 does not supply the 4-400A filament volts, just the 6.3V for the dial 
lights
and the full wave diode tubes for the screen supply.

I guess this would also extend the life of the xfmr perhaps?

https://www.mediafire.com/view/8uy1f2fn5ygqa27/T103.jpg/file


Anyhow, I can tell the "0" common is black, but not sure which are the other 
2.
I tried the ohmmeter / DMM but the decimal readings are pretty small so 
wanna be sure.
Any other way to check this?


--
Steve Hearns
KA2PTE