ADJUSTMENT INSTRUCTIONS
VSafety PrecautionsOSECAM-L' Adjustment
1. It is safe to adjust after using insulating transformer between
the power supply line and chassis input to prevent the risk ofNOTE :This adjustment should be performed after PIF
electric shock and protect the instrument.adjustment.
2. Never disconnect leads while the TV receiver is on.
3. Don't short any portion of circuits while power is on.Test Point : TP1
4. The adjustment must be done by the correct appliances.
5. Unless otherwise noted, set the line voltage to 230Vac!10%,Adjust : VR102
50Hz.
1) Turn on S1 and S3 and off S2.
VTest Equipment required
2) Adjust VR102 so that the DC voltage may be indicated
1. RF signal generator (with pattern generator)
2.5!0.1Vdc.
2. DC Power Supply
3. Multimeter (volt meter)
4. Oscilloscope
5. Color analyzer
ORF AGC (Automatic Gain Control) Adjustment
Main Board(Component side view)Test Point : J209 or Observing Display
Adjust: VR101
V Multimeter or Oscilloscope
1
The RF AGC control (VR101) was aligned at the time of
IC101
manufacture for optimum performance over a wide range
Power-JP7 IC05TDA4474
Supplyconditions. Readjustment of VR101 should not be necessary
5VJP4 IC102unless unusual local conditions exist, such as ; TP124Signal-
0.01pF Generator
5V7JP138.9MHz (B/G,D/K,I,L)
L107
11 JP234.25MHz (SECAM-L')1) Channel interference in a CATV system.
4.7k1
S3162) Picture bending and/or color beats, which are unusually due
JP5VR102to excessive RF signal input when the receiver is too close
Q106
to a transmitting tower or when the receiver is connected to
S2VR102
an antenna distribution system where the RF signal has
100115
JP3been amplified. In this case, the input signal should be
1001
attenuated (with pad or filter) to a satisfactory level.
S13) Picture noise caused by "broadcast noise" or weak signal.
If the broadcast is "clean" and the RF signal is at least 1mV
(60dBu), the picture will be noise free in any area.
Fig. 1 : Connection Diagram of Equipment for PIF Adjustment
Adjusting the VR101(RF AGC) control to one end of rotation
will usually cause a relatively poor signal to noise ratio;
Adjusting to the other end of rotation will usually cause a
degradation of over load capabilities resulting in color beats or
OPIF (Picture Intermediate Frequency) Adjustment
adjacent channel interference. For best results, adjust the
VR101 control while performing on all over local channels, or
Test Point : TP1the voltage at TP2 will be 2.3!0.1Vdc in RF level 65!1dBuV.
Adjust : L107
1) Connect the measuring equipment to the Main Board as
shown in Fig.1.
2) Set RF frequency and output level of RF SIGNAL
GENERATOR as shown Table 1.
3) Turn off S1 and S3 and on S2.
4) Adjust L107 so that the DC voltage may be 2.5!0.1Vdc.
SystemFrequency ModulationOutput levelAdjust
B/G,D/K/I,SECAM-L 38.9MHzOFF10mVp-pL107
SECAM-L'34.25MHzOFF10mVp-pVR102
(Table 1)
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ACEC
