High Voltage Inspection; Focus Adjustment; Safety Inspection - Toshiba 21E88 Service Manual

3. High Voltage Inspection

Measure voltages of test points on the main PCB with the digital voltmeter. Measure the CRT high
voltage with the high-voltage testing equipment and heater voltage with the high-frequency
effective voltmeter. The rated values are shown as below.
Test Point
Negative of VD603
Negative of VD855A
CRT anode
Heater

4. Focus Adjustment

Caution: Dangerously high voltages are present inside the TV. Extreme caution should be
exercised when working on the TV with the back removed.
4.1 After removing the back cover, look for the FBT on the main PCB. There should be a FCB on the
FBT.
4.2 Power on the TV and preheat it for 15 min.
4.3 Receive a normal TV signal. Rotate knob of the FCB until you get a sharp picture.
Before Adjusting

5. Safety Inspection

5.1 Inspection for insulation and voltage-resistant
Perform safety test for all naked metal of the TV. Supply high voltage of 3000V AC, 50Hz (limit
current of 10mA) between all naked metal and cold ground. Test every point for 3 sec. and ensure
no arcing and sparking.
SERVICE MANUAL
Table 2
25¡ À 1.5V (for BSC6OU FBT only)
27¡ À 1.5V (for BSC62V1 FBT only)
195¡ À 5.0V
25¡ À 1.5KV (for IRICO£ ¬ SHANGHAI NOVEL, LG, CHUNGHWA£ ¬
and THAI CRTs)
27¡ À 1.5KV (SAMSUANG£ ¬ BMCC)
6.3¡ À 0.3Vrms
Fig. 4
9
Voltage (V)
After Adjusting