Alignment and Adjustments
4-2 Alignment and Adjustment
4-2-1 General Alignment Instructions
1.Usually, a color TV needs only slight
2.Observe the picture and check for good back and white details. There should be no objectionable color shading: If color shading is present, demagnetize the receiver. If color shading persists, perform purity and convergence adjustments described below.
3.To protect against shock hazard, use an isolation transformer.
4-2-2 Power Supply Check
Check the following:
A:Power plug is connected;
B:Power On when “Power ON” button is pressed
C:Power On by FBT Each supply is marked on
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4-2-5 IC902 Replacement
1.When IC902 is replaced, all values are reset to “Initialized MICOM Data” and readjustment is necessary.
2.Press the POWER button 10 seconds after
3.To enter the Service Mode, refer to Fig.
4-2-6 PIF VCO Adjustment
1.Use a Pattern Generator or an
2.Open pin 11 of Micom (IC901) or one side of lead pin for R237.
3.Adjust VCO in the service mode to set IC101 Pin 44 (AFT) to 2.5V ± 0.4V.
4.Connect the opened site.
Adjust the focus control on the FBT for well defined scanning lines.
4-2-4 Fail Safe Circuit Check (FS) (OPTION)
1.The failsafe check must be the final step in servicing.
2.Turn the power switch ON and adjust customer controls for normal operation.
3.Temporarily short pin X to pin R on the main board (RX06, RX04) with a jumper wire. Raster will disappear.
4.The TV must remain in this state even after removing the jumper wire. This shows that the failsafe circuit is working properly.
5.To recover picture and sound, temporarily turn off the TV and allow the failsafe circuit more than 30 seconds to reset. Then switch power ON to produce normal picture and sound.
4-2-7 RF-AGC Adjustment
1.Input a PHILLIPS pattern.
2.Set the input signal to 60 dB.
3.Enter into the AGC in the service mode.
4.Adjust AGC until color bar noise disappears.
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