Hitachi VK-U174 Service Manual page 27

Troubleshooting > Trouble Diagnosis
(8) No auto focus operation
Does zoom
No
operate
normally?
Yes
Connect an
oscilloscope
to video output
No
VIDEO SIGNAL:
360mVp-p or more
Yes
Set the zoom to the
wide-angle end.
Point at the objects
Note: For the item marked #, perform all
from the infinity to
close-up ends.
Is there a point at #
Yes
which focus is obtained
between the infinity
and close-up ends?
No
Yes
TL4005 or
IC2507-39 :
Pulse
No
C h e c k t h e
No
c o n n e c t i o n s o f t h e
l e n s f l a t c a b l e .
Yes
No
T L 4 0 0 6 : 3 V
Yes
T L 4 0 0 7 o r No
I C 2 5 0 7 - 3 3 :
P u l s e
Yes
L e n s f a u l t y .
See "(4) No zoom and
focus operation."
Increase the
illumination
of the subject.
the adjustments required when the
unit is data initialized, before
adjustiNo auto focus.
Data Initialize and
adjust auto focuss.
C o r r e c t t h e
c o n n e c t i o n s
o f t h e f l a t c a b l e .
C h e c k t h e 3 V l i n e
I C 2 0 5 7 f a u l t y .
R 4 0 0 1 f a u l t y .
Q 4 0 0 1 f a u l t y .
Circuit No.
1000 to 1099
1100 to 2999
3000 and higher
No
Does the video
Camera circuit faulty.
level increase?
Yes
No
Does autofocus
operate normally?
Yes
END
T L 4 0 0 1 t o 4 0 0 4 o r
Yes
I C 4 0 0 1 - 1 2 , 1 4 , 1 0 ,
1 6 : P u l s e s
No
No
Check the 3V line
IC4001-8 : 3V
Yes
No
Check the 6V (VM)
TL4023 : 6V
line
Yes
No
IC4001-33 : Pulse
Yes
No
IC4001-32 : Pulse
Yes
No
IC4001-38 : Pulse
Yes
T L 4 0 2 4 : P u l s e
Yes
I C 4 0 0 1 f a u l t y .
4 - 8
Circuit Board
SP
PC
CSR
IC2507 faulty.
Lens faulty.
I C 2 5 0 7 f a u l t y .
I C 2 5 0 7 f a u l t y .
I C 2 5 0 7 f a u l t y .
I C 2 5 0 2 f a u l t y .