Zanussi 22ZT907 Service Manual page 23

PCB BS
Denomination
Adjustment procedure
Preliminary operations
Check that the p.c.b. is correctly supplied:
F12; +2OOV DC + 1OV on contact G5; +2.2V DC + 1OOmV on contact Fl;
12 Vpp on contact F14; 160 Vpp on contact G2; 11 Vpp on contact FlO.
Brightness and contrast controls to maximum (adjustment on remote
control when provided).
Colour saturation to minimum.
Grey scale signal in antenna. Correct tuning.
Adjust black-level potentiometers P105-P107-P109 to max. (clockwise)
Adjust gain potentiometers, ~104-P106-P108 to max. (anticlockwise).
Oscilloscope with attenuated probe on contact F2.
Check that the
2.65 Vpp.
Operations
Oscilloscope's
Adjust P105 to
Oscilloscope's
Adjust P107 to
Oscilloscope's
Adjust PlO9 to
Colour bar signal in antenna. Correct tuning. Saturation to max.
Oscilloscope's probe on TP102. Apply a 1 V DC voltage to TP103.
Adjust LlOl for max. amplitude of signal displayed.
Suppress voltage applied to TP103.
Plug in jumper S103. Disconnect SW102.
Adjust Cl23 for minumum bar horizontal drift.
Disconnect S103. Reconnect SW102.
Test 3 signal (delay) in antenna.
Oscilloscope's probe on red output (H4).
Adjust PI03 and, if necessary, L104-L105 so as to perfectly align the
bottom portion of the signal displayed.
Test 2 signal (phase) in antenna.
Adjust L102 for best superimposition of the two wave shapes displayed.
signal present on this point has a total width of
probe on red output (H4).
set the reference level (see figure 4) to 170V DC.
probe on green output (H2).
set the reference level to 170V DC.
probe on blue output (Hl).
position the reference level to 170V DC.
Luminance-chrominance and video
output amplifier.
25OmV on contact