EH Scott Radio Enthusiasts

The Fine Things are Always Hand Made

Is there a good picture of the underside of a early 7-knob Phantom, particularly the voltage divider resistor(s)? I need to build one.

Comment by David C. Poland on August 22, 2019 at 10:45pm

The early Phantom has a candohm unit riveted to the side of the chassis, (as do the other Scott models like the Masterpiece and Super 12 ). After all these years, if any sections are good, consider it fragile.  I have had to replace them.  The C- divider is by discrete resistors.

The Riders circuit diagram shows B+ resistor sections add up to 7560 ohms total. So I use an 50 watt 8000 or 9000 ohm adjustable ceramic power resister with 4 adjustable taps. I have been able to mount the resistor using the same holes as the original candohm mount holes. In particular Ohmite. Set the taps using an ohm meter, from ground working up the 250 volt tap

From the B+ end thus:  per Riders vol 14 page 37, 38 fold out

I actually connect the low end to the chassis ground, so, I measure up tap by tap to the last on to which 

The B+ line is attached. You should be able to locate the original wires for each tap.

250 volts incoming from pin 2 line of the cable plug.  

                 1975 ohms    to next tap

150 volts.  

                 780. ohms.     "   "     "

125 volts

                980. ohms

100 volts

                3825 ohms

to chassis Ground

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