Technics RS-TR474 Service Manual page 27

RS-TR474 |
Checking Method" on page 22.
The unit is not turned on.
YES
Does the power switch turn on ?
Is the voltage output at Q608
emitter approx. 5.6V ? ,
Is the voltage across R624
approx. 16V ?
NO
R624 replacement.
turned on and off ?
turned on and off ?
measured ?
FFC cable insertion check or —..
replacement.
Does the voltage at Q603 base
change from OV to 3.6V when
measured with the power switch
Does the voltage at CN3B pin 12
change from OV to 5V when
measured with the power switch
Does the voltage at CN3A pin 12
change from OV to 5V when
Microprocessor is normal.
Does the voltage at Q603
collector change from OV to
15V ?
Q603 soldering check or
replacement.
Q610 and —20V system check. }—
Does the voltage at Q604
collector change from —20V to
15V ?
D613 soldering check or
replacement.
R622 disconnection, or Q605
check or replacement. ;
Does the voltage at D613 change
fromOVto8.2V? .
Does the voltage at Q605 emitter
change from —0.4V to 7V ?°
Power is normal
| RS-TR474 RS-TR474
Power switch turns on but
mechanism does not operate
(common to both mechanism).
Voltage check:
Approx. 5V at CN1 pin 9 and CN2
pin 14
Approx. 7.5V at CN1 pin 13 and
CN2 pin 12 Connection a
Approx. 15V at CN1 pin 10 and
CN2 pin 13
OV (ground) at CN1 pin 12 and
CN2 pin 10
NO
Do open/close operations work
properly ?
YES
Check switches in the self-
diagnosis mode.
Is any switch failure stored in YES Replace any °
memory ? new one.
YES
NO
DECK 1: $801, S802
DECK 2: S803, S804
Unplug the power cord and force
. the door to the half-open position
by hand. '
When it is plugged in again, YES | Both power a
check the door closes correctly system are ni
with both door switches (S801
and $802) still in the off
positions.
NO
DECK 1: S801, $802, CN1 @
DECK 2: $803, S804, CN2 ®
Does the voltage at CN1 pin 3
change when the door switch NO
Switch failure
(S801 and $802) is forced into the
on position ?
YES
DECK 1: @
DECK 2:@
Does the voltage at the oa
microprocessor terminal also
change ?
YES :
Check conne:
motor PCB ar
To the microprocessor check :
section.