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I
High Voltage Hold-down Check/Adjustment
I
(BRV503)
Perform the following checks/adjustments when replacing the
following components (marked l:iiiiil on the schematic diagram).
l:iiiiilPA
board .... RV503, IC502, R524, R525, R526, R527, R530,
R808
1. Tum off the power.
2. Connect the static voltmeter to the CRT anode cap.
• Static voltmeter : Whose input impedance calibrated
to
above 2 x 10
9
Q.
(Example : Singer's ESH-27X or ESH-23X)
3. Connect a 200
kQ
variable resistor between TP501 and
GND of the PA board.
(Maximize the resistance of the 200 kQ variable resistor.)
4. Tum on the power.
5. Input the cross hatch signal.
6. Set the BRIGHTNESS YR and CONTRAST YR buttons to
the preset condition. (The LEDs (green) on the buttons go
off.)
7. Cut-off R, G, and B. (Turn on the SHIFT button (LED
lights up in orange), and turn on the
R,
G, and B buttons
(LEDS light up).)
8. Check that when the resistance of the 200 kQ variable
resistor connected to TP501 is gradually reduced, the high
voltage drops rapidly at the following values.
20-inch model : 30.00 kV ± 0.50 kV
14-inch model : 27.00 kV± 0.50 kV
9.
If
step 8 is not satisfied, replace RV503 of the PA board,
and adjust RV 503 so that the specification is satisfied.
10. Disconnect the 200 kQ variable resistor.
11. Check that the high voltage satisfies the following values.
20-inch model : 27.00 kV± 0.15 kV
14-inch model : 25.00 kV ± 0.15 kV
12. Disconnect the static voltmeter.
13.
If
replacing RV503 in step 9, after adjusting the RV, secure
RV503 using epoxy resin (DP-190 3M).
Beam Current Protector Check/ Adjustment
(BRV502)
Perform the following checks/adjustments when replacing the
following components (marked • on the schematic diagram).
l:iiiiilPA
board .... RV502, IC502, RlOl, R514, R515, R516, R517
PC board .... Rl, R2, R3, R4, RS, R6
BK board .... R912, R913, IC901
1. Tum off the power.
2. Disconnect the CN3 connector of the PC board.
3. Connect a DC ammeter between Pins G) and @ of CN3 of
the PC board.
4. Short-circuit Pin ® and © of CN3 using a jumper.
5. Short-circuit 11>502 and TP504 (GND) of the PA board
using a jumper.
6. Tum on the power.
7. Input the 100% all-white signal.
8. Set the BRIGHTNESS YR and CONTRAST YR buttons to
set the MANUAL adjustment condition. (The LEDs (green)
on the buttons light up.)
4-13
9. Gradually rotate the BRIGHTNESS YR and CONTRAST
YR from MIN to MAX, and check that the protector starts
operating when the readings of the ammeter becomes as
follows.
20-inch model : 2.0 mA ± 0.2 mA
14-inch model : 1.5 mA ± 0.2 mA
10. Replace RY502 if step 9 is not satisfied, adjust RY502so
that the specification is satisfied.
11. Disconnect the jumper between TP502 and TP504 (GND)of
the PA board.
12. Turn on the power again.
13. Check that when the BRIGHTNESS YR and CONTRAff
YR buttons are rotated from MIN to MAX, ABL operates
(the reading of the ammeter is as follows).
20-inch model : Below 1.5 mA
14-inch model : Below 1.3 mA
14. Disconnect the DC ammeter.
15. Disconnect the jumper between Pins®
and© of CN3of
the PC board.
16. Connect the CN3 connector of the PC board.
17.
If
RV502 is replaced at step 10, after adjusting the RV,
secure it with epoxy resin (DP-190 3M).
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