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When replacing parts shown in the table below, the following
operational checks must be performed as a safety precaution
against X-ray emissions from the unit.
HV ADJ
HV Protector
T901 (FBT), R917, R918, R923, R920,
Circuit
R919, R1004, C920, D911, D912
Beam Current
R933, R932, R921, R1006, D915,
Protector Circuit
D917, IC901, T901 (FBT)
HV Regulator
T901 (FBT), IC901, R924, R925,
Circuit
RV901
Allow the unit to warm-up for one minute prior to checking
the following conditions:
2-1. HV Regulator Check
1) Input white cross hatch signal. (fH = 106.3 kHz)
2) CONT and BRT Control normal condition.
3) Input voltage: 120 ± 2 VAC
4) Confirm that the voltage is within the voltage range shown
below.
Standard voltage: 27.0KV ± 0.2KV
5) When replacing components identified by
sure to recheck the High Voltage.
6) Verify the High Voltage as shown above (27.0KV
+0.2KV) is within specification. If not, RV904 on D board.
7) After adjusting the High Voltage within specification, put
the RV cover on RV901 as shown below and apply
sufficient amount of RTV around RV901.
2-2. HV Protector Check
All manuals and user guides at all-guides.com
SECTION 2
SAFETY RELATED ADJUSTMENT
Part Replaced (
)
RV901
Part Replaced (
)
, make
RV901
1) Confirm the voltage more than 15.0 VDC between D912
cathode and GND on D Board.
2) Using an external DC power supply, apply the voltage
shown below between cathode of D915 on D Board and
GND.
Confirm that the HV protector circuit (Hold down) works
and CRT screen disappears when applying the voltage
protector as shown below.
Standard DC Voltage: 21.1 +0.00 / - 0.05 VDC
Check Condition
• Input voltage : 120 ± 2 VAC
• Input signal : (fH = 31.4 kHz), Cross Hatch
• CONT and BRT Control: Normal Condition
2-3. Beam Current Protector Check
(Software Logic)
1) Using an external current source, apply 1.68mA from pin
of T901 (FBT) to GND on D Board. Confirm that the
software logic beam current protector works and that the
CRT screen disappears.
Check Condition
• Input voltage : 120 ± 2 VAC
• Input signal : (fH = 31.4 kHz), Cross Hatch
• CONT and BRT Control: Normal Condition
2-4. B± Maximum Check
1) Input white cross hatch (fH = 106.3 kHz) signal.
2) Beam control: Normal condition
3) Input voltage: 100 - 120 VAC
Note: Use NF power supply or make sure that
distortion factor is 3% or less.
4) Confirm that the voltage is within the voltage range
shown below.
Standard voltage: 195.0 -205.0 VDC
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