Important Safety Tests
Measuring H.V.
The anode caps are cemented to the CRTs. To gain access for high voltage measurement, remove the red CRT�s anode lead from the flyback transformer distributor. Grasp the anode lead protective cap at its bottom and squeeze it against the locking cap body inside, Rotate 1/4 turn counter clockwise and pull the anode lead sleeve out of the FBT distributor. Connect a high voltage lead (+) from your H.V. meter to the FBT distributor, and the common (-) to cold ground ( ). (See Fig. 2). 1 Grasp protective rubber cap 2 Push & rotate cap counterclockwise to remove Anode lead 3 Discharge to CRT Chassis Figure 4. DVM & Power supply connection. Connect the 15 ~ 25 V DC variable power supply to (+) FBT Distributor Figure 2. Removal of FBT leads TPD8 or IC802 pin 2 (D-Board) and (-) heat sink of Q551 (See Fig. 4). Procedures: 1. Apply a monoscope pattern. 2. Turn PTV ON. 3. Adjust the Picture or Brightness controls so that the DVM reads 12.4 volts ± 0.4 volts. 4. Increase the variable power supply until set turns off. The set should turn off at 12.4 volts ± 0.4 volts (DVM) and high voltage less than 36.4kV. 5. If the DVM reading is other than 12.4 volts (± 0.4 volts), readjust picture or brightness control and repeat steps 3. 6. Turn off the variable supply and confirm that the set will turn on with the Remote Control. 4. Connect a H.V. meter (static type, class 0.1) with high voltage leads to high voltage distributor on FBT. (See Fig. 4)
TPD51 TPD50 D-Board
+
-
DVM
MA150 100� 1/2 W
D-Board
IC802 PIN 2 OR TPD8 HEAT SINK OF Q551
(+) Variable Power (15~25DC) Supply (-)
Note:
Reinsert the anode lead into the FBT distributor until it is tightly and fully seated. Turn the locking cap clockwise to lock in place.
(EHT) Protector Operation Check
With the cabinet back removed, apply a nominal 120V AC to the PTV. Over Voltage Test Preparation: 1. Turn PTV �OFF� 2. Connect an NTSC signal generator to the antenna terminal. 3. Connect DVM (+) TPD50 and (-) TPD51 on D Board. (See Fig. 4) Cold Ground
FBT Distributor
