Notes Of Schematic Diagram 2.0 - Philips VR299/55 Service Manual

SECTION 4
CHARTS AND DIAGRAMS
NOTES OF SCHEMATIC DIAGRAM
Safety precautions
The Components identified by the symbol AN are
critical for safety. For continued safety, replace safety
critical components only with manufacturer's recom-
mended parts.
4. Units of components on the schematic diagram
Unless otherwise specified.
1) All resistance values are in ohm, 1/6 W, 1/8 W {refer to
parts list).
Chip resistors are 1/16 W.
K: K (1000 ), M: M (1000K }
2) All capacitance values are in pF, (P: PF).
3) All inductance values are in LH, (m: mH}.
4) All diodes are 159133, MA165 or 1N4148M (refer to parts
: list).
2. Indications of contral voltage
AUX : Active at high
AUX or AUX{L) : Active at low
3. Interpreting Connector indications
Removable connector
Wire soldered directly an board
Non-removable Board connector
Board to Board
1} | SePa SS] G29 EE
Connected pattern on board
The arrows indicate signal path
4, Voltage measurement
1) Video circuits
REC : Colour bar signal in SP mode, norma! VHS mode
PB: Alignment tape, colour bar SP mode, normal VHS
mode
— : Unmeasurable or unnecessary to measure
Audie circuits
REC : 1KHz, —8 dBs sine wave signal in SP mode, Nor-
mai VHS mode
PB: REC then playback it
Movie Camera circuits
Measured using a correctly illuminated gray scale or colour
bar test charts in the E-E mode
Ps
2
—
3
—
4) Indication on schematic diagram
Voltage Indications for REC and PB mode on the sche-
matic diagram are as shown below.
REC mode —-® 2.5 1.8
(5.0)
lee and REC modes
(Voltage of PB and REC modes
are the same)
PB mode
Note: If the voltages are not indicated on the schematic
diagram, refer to the voltage charts.
5. Waveform measurement
Video circuits
REC : Colour bar signal in SP mode, normal VHS mode
PB : Alignment tape, colour bar SP mode, normal VHS
mode
Audio circuits
REC : 1KHz, -8 dBs sine wave signal in SP mode, normal
VHS mode
PB: REC then playback it
Movie Camera circuits
Measured using a correctly iuminated gray scale or colour
bar test chatrs in the E-E mode
Indication on schematic diagram
Waveform indications on the schematic diagram are as
shown below.
ia Measurement point
Waveform number
_ —
2
—
3
—
=
5) Waveform indications
Waveform name or
measurement point
Waveform number
WF25 ALC OUT
REC/PB 1.2 Vp-p «——— Level : 1.2 Vp-p
(80 mv/2 mseo/DIV
Oscilloscope Volts and Time/Division, Probe 10: 1
Mode : REC or PB modes
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