Safety Related Adjustment - Sony TRINITRON KV-20M20 Service Manual

SECTION 4
SAFETY RELATED ADJUSTMENTS
A BOARD
Meee CONE IB TON ME too IBY HOD own B+ VOLTAGE CONFIRMATION AND ADJUSTMENT
The following adjustments should always be performed when : '
replacing the following components (marked with [4 on the
The following adjustments should always be performed
schematic diagram). when replacing the following components.
(marked with [d on the schematic diagram).
1C301, 1C502, IC601, D505, D506, D507, D510, DY, C503,
C511, C513, C528, R511, R519, R520, R523, R525, R527, R559, 1C001, C601, RO3O, R617, R618, R629, R630, R651,R652,
R560, R617, R618, T504 (FBT) R654, R655, R656
1. Preparation before confirmation 1) Supply 130 + 2° V AC to the set with a variable auto trans-
former.
1) Turn the POWER switch ON. Input an entirely white 2) Input a dot signal.
signal and set the PICTURE and BRIGHT controls to 3) Set the PICTURE control and the BRIGHT control to
maximum. minimum condition.
2) Confirm that the voltage at TP85 is more than 90VDC 4) Set to service adjustment mode.
when the set is operating normally with 120.0+2.0 VAC 5) Select PADJ with [i] and [4] .
supply. 6) Adjust with [6] to the 0 level.
7) Confirm the voltage of ABOARD TP-91 is less than 123.0V
2. Hold-down operation confirmation DC.
8) If step 7) is not satisfied, replace the components, repeat the
1) Connect the current meter between Pin 11 of the FBT above steps.
Se and the PCB land where Pin 11 would normally 9) Supply 120.0 + 2.0 VAC to the set with a variable auto trans-
: former.
2) Input a white signal and adjust the ABL current to be ; '
1440 + 1O0WA using the PICTURE and the BRIGHT _—_—!0) Adjust with [3] and [| for the 116.7 + 0.5V DC.
controls. 11) Write into the memory by pressing then
3) Confirm the voltage of A board TP-91 is 113.2 40.5
VDC
4) Connect the Digital Voltmeter and DC power supply
via 188119 to TP-85.
5) Increase the DC power voltage gradually until the
picture blanks out.
6) Read the digital voltmeter indication.
7) Turn DC power source off immediately.
STANDARD
Less than or equal to 127.0 VDC
8) Input a dot signal and adjust the ABL current to be
95+100/-95uA using the PICTURE and the BRIGHT
controls.
9) Confirm the voltage of A board TP-91 is 116.7 + 0.5
VDC
10) Repeat steps from (4) to (7).
STANDARD
Less than or equal to 127.0 VDC
3. Hold-down readjustment
If the current setting indicated in step 2-2 cannot be met,
readjustment should be performed by altering the resistance
value of R525 (a component marked with }4).
T504
FBT
ammeter
3.0 mA de
ake'
procs aeccnwouoce QWeeewenansooseen
Sara