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Saturday 10-6

Sunday 12-5

Early Television Early Television
Early Television Early Television

Early Television

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The Set: Pete Deksnis's Site about the CT-100

Restoring a Vintage Color Television Set


12BH7 Vert. Osc.-Amp. Restoration

Replace seven paper capacitors with modern equivalents

C104(Sams) / 1C242(RCA) = 0.1 uF
C105(Sams) / 1C241(RCA) = 0.22 uF
C106(Sams) / 1C238(RCA) = 0.15 uF
C107(Sams) / 1C240(RCA) = 0.001 uF (1600v)
C108(Sams) / 1C212(RCA) = 0.47 uF
C109(Sams) / 1C211(RCA) = 0.22 uF
C110(Sams) / 1C210(RCA) = 0.1 uF

Four of the seven capacitors appear in the photo.

Early Television

With an external power supply connected to the 5.6K 2-watt power resistor [1R277(RCA); R149(Sams)] shown in the photo above AND to the 4.7K 1/2-watt resistor [1R301(RCA); R144(Sams)] on the wiper of the Height control AND with the yoke assembly plugged into the octal socket on the back of the high-voltage cage, you can check for the waveform below [Sams W10].

Early Television

NOTES: Isolate the 12BH7 circuit from the rest of the CTC-2 chassis for the above test as follows: Disconnect both resistors from the B+ bus before applying power to this circuit.

(a.) 5.6K 1R277 is located below the chassis as shown in the photo above.
(b.) The hot end of 1R301 is easily lifted from its tie point underneath the chassis; that resistor is found a few inches to the left and below the first resistor.

The ballast assembly that plugs into a socket on the back of the rectifier cage should NOT be installed.