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HITACHI HT-464
TROUBLESHOOTING
D57 @ terminal: 15.5 V
D57 © terminal:
— 16.8 V
ZD55 cathode side: —10.8
V. Q57 emitter: 7.2 V
Platter does not rotate.
Tone arm does not perform auto-in.
Approx. 7 V voltage at pin
NO
ee
Defective 1C04
Bof 1CO4?
VYES
4
Is 0 V produced when power
switch is set to ON and the
start/cut button is depressed?
NO
Defective start/cut
switch
YES
a
Output betwen O10
collector,emitter?
YES
Output at Q56 emitter?
; Ce
a
OS
YES
Output at pin of 1C52?
YES
(Now rotate platter by hand.)
Oo
:
t——*|
Defective Q10
O
Defective Q56
NO
Defective 1C52 or
*|
motor
Output at Q58, 60 emitter?
Does platter move when
tone arm is brought
manually to inside circum-
ference of platter?
O
Defective Q58—61
or
motor
el
Defective wiring
|
NO
Check D14.
|
Defective D14
]
yyes
YES
NO
Set power switch to OFF and
Check D10.
+--+
Detective D10
|
check wiring from switch
yves
P.W.B. to P.W.B.
a
YES
OV between Q56
Ne
Defective Q55
collector,emitter?
Check DC motor belt
YES
Is anode of D12 about
—0.5 V
when the tone arm is at the
arm rest position?
YES
About 7 V at pin 3° of 1CO1?
About 7 V at pin '4 of 1C03
when start/cut button is kept
in depressed position?
PYES
—
Replace belt.
(Now set power switch to ON.)
eDUcEaae
Defective D12, CdSQ2
Defective
Defective
Ld
|
NO
Check that DO3 lights.
Pee
Defective D03
al
YES
NO
More than 4 V at D12?
p——™|_ Defective CdS02
VYES
rr
NO
Check
D10
t-——*)|
Defective D10
PYES
[ Check between 055 collector,
emitter
L
|
pNO
r
Further checks identical to
those under "Platter does not
rotate" in inspection 2.
= 4152
About 5 V or more at pin 6
of C03?
_
yNo
1 NO
[ Check D08.
}-—~—e[ Defective D08
yyes
—
NO
[ About 6 V at Q03 base?
BS ee
Defective Q03, DO9
YES
EN
O
Defective 1|CO2;
}
?
,
[About 0 V at pin ® of C027} NO | Defective 1002,
J ves
About 7 V at pin 40 of 1c03, | NO
about 0 V at pint?
'|
Defective 1CO3
"PES
About
7 V at pin 40 of (C01, 0
O
=
| V a¥oin ip? Eye ae ere'
t———|
Defective 1CO1
HES
[_ Defective Q04—08, DC motor _]
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