Safety Related Adjustments - Sony TRINITRON KV-27TW77 Service Manual

TH/27
Z27iv TW78
KV- 32TW77/32TW7 48
SECTION 4
SAFETY RELATED ADJUSTMENTS
Ba R511 CONFIRMATION METHOD (HOLD-DOWN
CONFIRMATION) AND READJUSTMENTS
The following adjustments should always be per-
formed when replacing the following components
(marked with [d@ on the schematic diagram).
PM501, R511, R632, R645, R650
®
1. Preparation before confirmation
1) Remove R635 on the D board and connect a
variable resistor (RV1: about 4.7k2-10k?2 )
between pin @ _ of IC601 and B+ line.
2) Supply 130+42.0V AC to with variable auto-
transformer.
2. Hold-down operation confirmation
1) Turn the POWER switch ON, and receive
entirely white signals and adjust ABL current to
1760£50yA with PICTURE and BRIGHT etc
controls.
2) Increase B+ line voltage gradually by adjusting
the resistor of RV1. Confirm that the minimum
voltage is less than 142.5V DC (27 inch) 140.0V
DC (32 inch) whereby the raster disappears
during operation of hold-down circuit.
NOTE: When the hold-down circuit starts
operating, switch OFF the POWER of
the set immediately.
3) Turn the POWER switch ON, and receive dot
signals and adjust ABL current to 160+50uA
with PICTURE and BRIGHT etc controls.
4) Increase B+ line voltage gradually by adjusting
the resistor of RV1. Confirm that the minimum
voltage is less than 143.5V DC whereby the
raster disappears during operation of hold-down
circuit.
NOTE: When the hold-down circuit starts
operating, switch OFF the POWER of
the set immediately.
3. Hold-down readjustment
When step 2 is not satisfied, readjustment should
be performed by altering the resistance value of
R511 (a component marked with B4).
ba R524 CONFIRMATION METHOD (HOLD-DOWN
CONFIRMATION) AND READJUSTMENTS
The following adjustments should always be per-
formed when replacing the following components
(marked with [@ on the schematic diagram).
1C601, PM501, D504, R509, R524, R634, R635, T501
@
1. Preparation before confirmation
1) Turn the POWER switch ON, and receive
entirely white signals and set the PICTURE and
BRIGHT controls to maximum.
2) Confirm that voltage of the check terminal of
TP-81 (D BOARD) is more than 114.0V DC (27
inch) 122.3V DC (32inch) when the set is
operating normally with 120.0+2.0V AC supply.
2. Hold-down operation confirmation
1) Turn the POWER switch ON, and receive
entirely white signals and adjust ABL current
to 1760+50nA with PICTURE and BRIGHT
etc controls .
2) Apply DC voltage of over 130.0V DC gradually
to the check terminal of TP-85 (D BOARD)
via 1T40 from the DC stabilized power source.
Confirm that the minimum voltage is less than
137.5V DC (27inch) 143.5V DC (32inch)
whereby the raster disappears during operation
of hold-down circuit.
NOTE: When the hold-down circuit starts
operating, switch OFF the POWER
of the set immediately.
3) Turn the POWER switch ON, and receive dot
signals and adjust ABL current to 160+50ynA
with PICTURE and BRIGHT etc controls .
4) Apply DC voltage of over 130.0V gradually to
the check terminal of TP-85 (D BOARD) via 1
T40 from the DC stabilized power source.
Confirm that the minimum voltage is less than
138.0V DC (27inch) 144.1V DC (32inch)
whereby the raster disappears during operation
of hold-down circuit.
NOTE: When the hold-down circuit starts
operating, switch OFF the POWER
of the set immediately.
3. Hold-down readjustment
When step 2 is not satisfied, readjustment should
be performed by altering the resistance value of
R524 (a component marked with Ba).