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#1
03-05-2013, 01:28 PM
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Hi All;
Old Coot, again you are right, I have NO resistance from the Center tap of the transformer to ground.. I didn't notice their relationship, while taking things out.. I am in the process of measuring these for a resistance value.. Both the Horizontal and Vertical Pots measure about 20 ohms and the wipers work in both of them.. Then I will connect the ion coil and the focus coil and let you know what changes.. THANK YOU marty 
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#2
03-05-2013, 02:00 PM
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Hi All;
Good News, I measured the Ion Trap Coil with the 56 ohm resistor accross it and got 22.9 ohms, just like Bob did.. The Focus coil measures about 240 ohms.. And After connecting that part of the circuit up.. I GOT on pin 8 of the Rectifier 330 Volts with the Variac set at 60 Volts, I didn't dare take it up any further.. Now to connect the 275 Volt voltage divider circuit and see what happens.. THANK YOU Marty
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#3
03-05-2013, 02:07 PM
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Say hey!
 Good goin' amigo.  
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#4
03-05-2013, 02:30 PM
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Hi All;
More good news, I hooked up the 275 Volt lead, and at pin 8 of the rectifier, I get 302 Volts, with the Variac set at 115 volts and the Bulb lit anyway.. With one rectifier tube.. Special Thanks to Old Coot.. Now for another wire the one going to C223A.. THANK YOU Marty
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#5
03-05-2013, 03:16 PM
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Geister,
It might help to simplify what's going on in that circuit. It uses what's called a 'back bias' scheme to generate negative voiltages for various other circuits in the chassis. It's used extensively in '30s radios with power trannys and in a lot of early TVs. First visualize the CT of the HV winding going directly to ground, and the rectifier tube putting out full B+. Now visualize a resistor from the CT to ground. As the rest of the tubes pull current, a voltage is developed across that resistor, and it's negative with respect to ground. The resistor can then be tapped (or a daisy chain of resistors used) to obtain specific negative voltges.
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#6
03-05-2013, 03:25 PM
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Hi All;
I got all the wires hooked up.. And it didn't drag anything down, which is the good news.. With one Rectifier tube and the 40 watt light bulb in series after the Variac.. Here is what my readings show, the bulb is dimly light.. 105 volts on the Variac Rectifier pin 8 307 volts, shows on schematic +300 volts 275+ divider tap 238 volts 135+ divider tap 185 volts -100 on cap -13 volts -18 on divider tap -5 volts -2 0n divider tap -.5 volt THANK YOU Marty
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#7
03-05-2013, 03:58 PM
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Lookin' good. At this point you could get rid of the Bulb, and start putting all the tubes back in except the horz output, watching the B+ reading as you add tubes.
As more and more tubes pull current and load the power supply, the B+ should come down and the negative supply rail should come up (though it probably won't show the full -100V yet). Finally if all's well at full line voltage, add the H output tube, being ready to shut the set off quickly if needed. Hold an insulated screwdriver next to the 1B3's plate connector and see if you can draw an arc. It should draw a healthy 'air arc' of a quarter inch or more, proving the H output and fly are running. If no arc, shut 'er down.
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