Section 3: Safety Related Adjustments; (Hv Hold-Down Confi Rmation) And Readjustments; B+ Voltage Confi Rmation And Adjustment - Sony TRINITRON KD-27FS170 Service Manual

3-1. X R529, R530, R531, R577
CONFIRMATION METHOD
(HV HOLD-DOWN CONFIRMATION) AND
READJUSTMENTS
The following adjustments should always be performed when replacing
the following components which are marked with Y on the schematic
diagram:
Part Replaced (
Y
C507, C511, C513, D519,
D520, D521, IC001, IC501,
IC601, IC602, PH601, R529,
R530, R531, R577, T502,
T503 (FBT), T505
Preparation Before Confi rmation
1. Using a Variac, apply AC input voltage: 120 +/- 2.0 VAC.
2. Turn the POWER switch ON.
3. Input a white signal and set the PICTURE and BRIGHT controls to
maximum.
4. Confi rm that the voltage of more than 23.0 VDC appears between
TP85 and ground on the A Board.
Hold-Down Operation Confi rmation
1. Connect the current meter between Pin 11 of the FBT (T503) and
the PWB land where Pin 11 would normally attach. (See Figure 1).
2. Input a dot signal and set PICTURE and BRIGHTNESS to
minimum: IABL = 2175 + 100/ -325 µA.
3. Confi rm the voltage of A Board TP91 is 134.6 ± 1.0 VDC.
4. Connect the digital voltmeter and the DC power supply to TP85 and
ground. (See Figure 1).
5. Increase the DC power voltage gradually until the picture blanks
out.
6. Turn DC power source off immediately.
7. Read the digital voltmeter indication:
Standard = 24.78 + 0.0/ - 0.1 VDC.
8. Input a white signal and set PICTURE and BRIGHTNESS to
maximum: IABL = 2175 + 100/ -325 µA.
9. Repeat steps 4 to 7.
KD-27FS170/32FS170/36FS170

SECTION 3: SAFETY RELATED ADJUSTMENTS

) Adjustment (
HV HOLD-DOWN
R529, R530, R531, R577
Hold-Down Readjustment
If the setting indicated in Step 2 of Hold-Down Operation Confi rmation
cannot be met, readjustment should be performed by altering the
resistance value of R529, R530, R531 and R577 component marked with
X.
)
R529 R577
R531 R530
DC Power Supply
3-2. B+ VOLTAGE CONFIRMATION AND
ADJUSTMENT
Always perform the following adjustments when replacing the following
components, which are marked with Y on the schematic diagram on the
A Board:
1. Using a Variac, apply AC input voltage: 130 + 2.0/-0.0 VAC
2. Input a monoscope signal.
3. Set the PICTURE control and the BRIGHT control to
minimum.
4. Confi rm the voltage on A Board between TP23 and ground is less
than 136.5 VDC.
5. If step 4 is not satisfi ed, replace R529, R530, R531 and R577 on A
Board and repeat the above steps.
KD-27FS170/32FS170/36FS170
digital multimeter
+
-
T503
TP85
TP85
FBT FBT
ammeter
3mA DC range
+
-
A
+
-
Figure 1
Adjustment (Y)
A BOARD
IC600, PH602
35