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55 FWD Mode)
1 the drum has been replaced.
fP (PBRF) and CH-2 to TP
servo) and load test tape TY-
ATF
REC MODE
STANDARD
=
ened
NG
44,1kHz
48kHz
» STANDARD (ATF: OFF)
' or REC (OFFSET: + or —),
at the oscilloscope RF signal
1igh-low is repeated.
g in.
1 the REC MODE switch set
2 switch set to PLAY or REC
1 the REC MODE switch set
. switch set to PLAY or REC
veform peak value (B) is 60
(2) Confirm that the undershoot level of the RF signal waveform's
flat portion is within 10%.
B
= or less
70°" less
70 °° le:
7. When the measured values are not within the above toleranc
repeat items 3 — 6 above.
Adjustment Point: mechanism assembly
DPG Adjustment
Perform the following adjustment without fail when the drum has
been replaced.
Adjustment Procedure:
1.
Connect oscilloscope CH-1 to TP (PBRF) and CH-2 to TP (SWP)
on the main board. (Use CH-2 as the trigger. When the CH-2
signal is inverted, the trailing edge can be used for synchronization.)
. Put the set into the test mode (main. servo) and load test tape TY-
7252 (8-909-822-00).
. Set the REC MODE switch to LONG (ATF: ON) and the TIMER
switch to OFF (OFFSET: 0).
. Press the AMS (C€4) key.
. Press the <4 and P® keys as appropriate so that the gap between
the oscilloscope SWP and RF signals becomes 650 + 15 psec.
(Hold the <4 and B® keys down for more than | second to
perform rough adjustment. Hold them down for approximately
0.2 seconds for fine adjustment.)
RF (PBRF)
f]
1
|
SWP
————~on-{
650 + 15u sec
ATF Pilot (GCA) Check
Perform this adjustment after cleaning the heads with a cleaning
cassette.
Check Procedure:
1.
Connect oscilloscope CH-1 to TP (GCA: Gain Control Amp.) and
CH-2 to TP (SWP) on the main board. (When the CH-2 signal is
inverted, the trailing edge can be used for synchronization.)
. Put the set into the test mode (main - servo) and load test tape TY-
7111 (8-909-8 12-00).
3. Actuate the PLAY (®) mode and check that the GCA waveform
on the oscilloscope is as follows.
(When the output level of Bch is low)*
GCA
(When the output level of Ach is low)*
ir
ce
ee
"
Ach
Bch
Ach
* Slightly changes depending on the state of the head. NG if the
GCA waveform is 1V or more or equal to the GND level.
3-2.
CHECKS FOR DATE FUNCTION
Clock IC Back-up Check
¢
When there is the short-circuit position on the pattern around the
lithium battery (BAT301) or the clock IC (IC330) ordisconnecting
CN151 on removing the front panel assembly the clock is reset.
(In spite of pressing PRESENT button, the data indication be-
comes "— —¥ ~-M——p"
At this time, check the back-up function by the procedures given
below.
(1)
Connect DC voltmeter to TP (BATT+) and TP (BATT -) on
the main board.
(2) When the power is off, the voltage value of the item (1) should
be less than +30 mV.
(When the voltage value becomes +30 mV or more, Check
around IC330 or replace 1C330.)
(3) When the power is on, the voltage value of the item (1) should
be less than 0 mV (— (minus) indication).
(When the voltage value becomes + (plus) indication, Check
around D321 or replace D321.)
(4) When the above voltage values are normal, set the preset date
and time (year, month, day, day of the week, hour, minute,
second) according to the instruction manual.
(5) After setting the time on the item (4), turn power off and turn
power on several seconds later, and check the clock works
normally.
Back-up Battery Replacement
The life of the back-up battery under normal use (normal tempera-
ture, normal humidity) is approximately ten years or more. (On the
instruction manual, described "approximately seven years".)
Be careful about the following points on the battery replacement.
* Repair the cause of the battery wastage by performing mentioned
above "Clock IC Back-up Check".
* The open-circuit voltage of the replaced battery is 3.0 V or more
as the new one, and when it is 2.0 V or less, it is completely
consumed, replace it with new one.
«
Afterthe battery replacement, perform "Clock IC Back-up Check"
again and set the time.
Clock Frequency Adjustment
Adjustment Procedure:
1. Connect a frequency counter to pin ® of 1C330 and GND on the
main board.
2. Turn power on and confirm that the reading on the frequency
counter is 2048.00 + 0.02 Hz. (in normal temperature)
3. Perform "Clock IC Back-up Check" described above.
* Time setting procedure described on page 9.
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