ERISSON SF21GA63, Service Manual

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SERVICE MANUAL
7
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
I
2
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.
Table 1
Test Point Voltage (V) Test Point Voltage (V)
TP-130V
130V
±
1.5V
TP-20V
20V
±
1V
TP-17V
17
V
±
1V
TP-5V-2
5V
±
0.3V
TP-5V-1
5V
±
0.3V
TP-8V
9V
±
0.5V
TP-11V
11V
±
1V
TP-26V
26V
±
1V
TP-200V
190V
±
5V
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.