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KRC-754 D/L
CIRCUIT DESCRIPTION
15
a
ees Sl
ree
- WCON A/D Port
LR
GND
(Note)
S¥5 is not connected with KEY3 and KEY4.
6. Test mode
After the occurrence of Reset when Vdd is supplied,
press and hold the " 4"
and "SDK(PRP)"
keys while press the Power key to ON to enter the test mode.
(The test mode includes
the cha-
nge of CE term
inal from "Lo" to "High" immediately after the power is switched ON. )
The test mode consists of the following processes.
Loud is turned OFF,
Bass,
Tre.,
Bal, and Fad. are set to "flat",
and the Volume level is set
to "00dB".
When the power is switched ON,
the Tuner source,
FMWi band and the last frequency are selected,
and
the LCD is set to the all-ON state.
However,
if the test mode is initiated with a tape
inside
the
set,
the set is turned ON with the tape source and the LCD is not set in the all-
ON state.
when the power is switched ON, the CKOUT output terminal outputs division (4. 19MHz) of system
clock for use in the adjustment
of reference oscillation
frequency of the clock.
When the Source key is pressed to ON or a tape is inserted,
the LCD all-ON state is canceled
and the set enters
the mode for S-meter adjustment.
In the S-meter test mode,
the S-meter level for the F¥ band of the tuner source is adjusted
to
20dB (0. 3V), and ">
lights when the level is exceeded.
With the AM band,
the SD level is adjusted,
and "<Q" lights when SD is detected.
The S-meter
test mode is not released even when the source
is changed.
However,
as it uses the " <q p> " display,
which is usually used with the tape system,
when a
source
change is detected,
the tape should not be in the set in this mode.
The test mode is released when the power is switched OFF then to ON, when panel is detached
then attached,
or when CE changes from "L" to "fl". However,
the states sect in the test mode
are not released and the current state is mainteined (except for Reset after Vdd is suplied).
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