Circuit Adjustments; Degaussing; Confirmation And Adjustment For Voltage - Toshiba 21E88 Service Manual

CIRCUIT ADJUSTMENTS

Preparation:
Circuit adjustments should be made only after completion of set-up adjustments.
Circuit adjustments can be performed using the adjustable components inside the TV set. For TVs with
2
I C bus control, first change the bus data.

1. Degaussing

A degaussing coil is built inside the TV set. Each time the TV is powered on, the degaussing coil
will automatically degauss the TV. If the TV is magnetized by external strong magnetic field,
causing color spot on the screen, use a specific degausser to demagnetize the TV in the following
ways. Otherwise, color distortion will be shown on the screen.
1.1 Power on the TV set and operate it for at least 15 minutes.
1.2 Receive red full-field pattern.
1.3 Power on the specific degausser and face it to the TV screen.
1.4 Turn on the degausser. Slowly move it around the screen and slowly take it away from the TV.
1.5 Repeat the above steps until the TV is degaussed completely.

2. Confirmation and Adjustment for Voltage

Caution: +B voltage has close relation to high voltage. To prevent X-ray radiation, set +B voltage to
the rated value.
2.1 Make sure that the supply voltage is within the range of the rated value.
2.2 Connect a digital voltmeter to the voltage output terminal of the main PCB. Power on the TV and
set the brightness and sub-brightness to minimum. Ensure that the voltage from the main PCB
reads as follows.
2.3 Regulate voltage adjustment components on the power section until the +B the voltage reaches the
rated value.
Note:
It's impossible to check the power part separately from the main chassis board as the part is
mounted on the main chassis board. The power components, etc. should be checked for burnout
when power-on. If burned out, do not power on the TV again until the cause is found out.
SERVICE MANUAL
Test Point
Negative of VD851
Negative of VD852
Negative of VD854
Negative of VD857
Positive of C874
Positive of C878
Positive of C800
8
Table 1
Voltage (V)
118V¡À 2V
17V¡À 1V
11V¡À 1V
+1V
14V
-1.5V
9V¡À 0.5V
5V¡À 0.5V
5V¡À 0.25V