No Autofocus Operation - Hitachi VM-H675LA Service Manual

(4) NO AUTOFOCUS OPERATION

See "(1) NO ZOOM AND
No
Does zoom operate
FOCUS OPERATION".
normally
Yes
Is manual focus No
1
provided
Yes
Can switching be done
No
Check the focus
between manual focus
switches.
and autofocus
Yes
• Focus switches faulty
NG
• R1179 faulty
IC1104-92: PULSE
• R1186 faulty
• C1118 faulty
OK
• Focus switches faulty
NG
• R1178 faulty
IC1104-93: PULSE
• R1185 faulty
• C1117 faulty
OK
1
Connect an oscilloscope Note: Check the items marked
to video out. focus FAR and NEAR switches alternately.
2
NG
Focus switches faulty
OK
by pressing the manual
2
No Increase the illumination
VIDEO SIGNAL:
360mVp-p or more of the subject.
Yes
Does the video level
increase
Set the zoom to the
wide-angle end
(Set the autofocus mode).
Point at the objects from
the infinity to close-up ends
Is there a point at
Check the IC1104 and
No
which focus is obtained
EEPROM.
between the infinity and
close-up ends
Yes
TL1312: PULSE
Initialize the unit and
adjust autofocus
Does autofocus No
IC1104 faulty
operate normally
Yes
Note: For the item marke
when the unit is initialized, before adjusting autofocus.
END
No
Camera circuit faulty
Yes
NG
4
OK
Note: Check the items marked by
3
turned power ON.
, perform all the adjustments required