H-Size Fails To Be Adjusted; Bad Focus - Compaq MV7540 Service Manual

6-4 H-Size Fails To Be Adjusted

The picture is too large and H-size can't be adjusted
Cut the collector of Q406 and look if the picture becomes
smaller, then check the voltage of circuit is half of B+.
Check the voltages concerned
with collector of Q406 as D406,
D407, L405, C422.
Connect collector of Q406 and cut base of Q406, then
look if the picture becomes small.
Replace Q406
Check the voltage of base of Q406 is between 0.5 and 1.1V when
adjust the H-size functional key.
Cut pin24 of IC401 and check if the voltage is between 3.0 and 2.3v
when adjust H-size function
Check the components betweenpin24 of IC401and base of Q406 as

6-5 Bad Focus

Readjust FOCUS control
NO
NO
YES
Q406, R434, R490, Q404, C421, R440, Q405 etc
NO
The picture is too small and H-size can't be adjusted
Check if the voltage of H-size control
transistor is half of B+.
YES
YES
NO
NO
Check focus control unit, CRT
socket and CRT.
20
NO
Replace D406
YES
Replace IC401
HP MV7540