Hitachi 27UX01B-501 Service Manual page 53

A B
1
2
3
4
5 1. Voltage measurement:
Boards Designation
- AC input to the Receiver is 120V.
NTSC (HD, 1125i & 525P when
applicable) signal generator is
• A-Board - Main Chassis
connected to the antenna of the
Receiver. (Color bar pattern of
• C-Board - CRT Drive
100 IRE white and 7.5 IRE black.)
• S-Board - 2nd Tuner Board
- All Picture and Audio adjustments
are set to Normalize.
• Y-Board - PIP Controller
TV ANT/CABLE - (Set-Up Menu)
in TV/ANT Mode
Volume - Min
TV/Video SW - TV position
Audio Mode - Stereo
C
Schematic Notes
Voltage Measurements
1. Resistors are carbon 1/4W unless 6.
- Voltage readings are nominal
noted otherwise.
and may vary ±10% on active
2. Capacitors are ceramic 50V unless 7. The schematic diagrams are current
devices. Some voltage
noted otherwise.
reading will vary with signal
3. Coil value notes is inductance in H.
strength and picture content.
4. Test point indicated by ; Test point but 8. Ground symbol
- Supply voltages are nominal.
no pin .
2. Ground symbol indicates ground
5. Components indicated with are
lead connection of meter.
critical parts and replacement should
Incorrect ground connection will
be made with manufacture specified
result in erroneous readings.
replacement parts only.
CAUTION: Incorrect ground
connection of the test equipment
will result in erroneous readings.
D E
A-Board Schematic (Left Portion)
Waveform Measurements
3
(BOLD LINE) indicates the
1. indicates waveform measurement. 5. Ground symbol
route of B+ supply. (Measurement can be taken at the waveform number indicates (Hot)
best accessible location in common ground lead connection of the
at the time of printing and are to the indicated point.) Oscilloscope.
subject to change without notice. 2. Taken with an NTSC signal generator
CAUTION: Incorrect
indicates HOT
connected to the antenna terminal.
connection of the test equipment will
GROUND CONNECTION;
(NTSC color bar pattern of 8 bars of result in erroneous readings.
indicates COLD GROUND. EIA colors, 100 IRE white and 7.5
IRE black.)
NOTE: All other component symbols
3. Customer Controls (Picture/Audio
are used for engineering
design purposes. Menu) are set to Normalize. Volume
is set to "MIN".
4. All video and color waveforms are
taken with a wideband scope and a
probe with low capacitance (10 to 1).
Shape and peak altitudes may vary
depending on the type of
Oscilloscope used and its settings.
F G
shown on
IMPORTANT SAFETY NOTICE
ground
N
ote:
THIS SCHEMATIC DIAGRAM INCORPORATES SPECIAL FEATURES
THAT ARE IMPORTANT FOR PROTECTION FROM X-RADIATION, FIRE
AND ELECTRICAL SHOCK HAZARDS. WHEN SERVICING IT IS
Obtain voltages using a
ESSENTIAL THAT ONLY MANUFACTURERS SPECIFIED PARTS BE
USED FOR THE CRITICAL COMPONENTS DESIGNATED WITH A IN
digital multimeter.
THE SCHEMATIC.
H