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JVC UX-A4 Service Manual page 57

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8. Main Adjustments
Test Instruments reqired for adjustment
1. Low frequency osciliator
(oscillation frequency: 50Hz to 20kHz)
( Output : 6 dBs with 60 Q terminator)
2, Attenuator( Impedance : 600 2 )
3. Test Tapes
VET712 secteccersssserteeeees For tape speed, wow and
flutter measurement
VETZ24 vrrtceeeceseerees For 3kHz reference level check
VETZSG ret tesesteeetserse
recess For playback frequency
response check
VTT752 srrrrsseeeee For playback channel check(1kHz)
4. Electronic voltmeter,
Distortion meter
5. Resistor...600 Q for attenuator matching
6. Torque gauges-ss++-*- Cassette type for CTG — N
mechanism adjustment
7. Wow and Flutter meter , Frequency counter
8, Extension cord for check -+++++++++ EXTUXT1 — KIT
i Measuring conditions (Amplifier section)
Sopply voltage AC 230V(50/60HZ};UX — A4 E/G/GI/EN
AC240V(50/60Hz):UX ~ A4B)
Reference output : Speaker ------- 0 dBs (0.775V) /4 2
: Headphone «--0 dBs (0.775V)/ 32 2
@ Standard position of functionswitches
Function switch verrrrrrsseresceseeeesessccrensevevcees TAPE
Tape select SWitch strssere ccc
rece secre res ccenes NORMAL
Timer , DOLBY NR , Active hyper bassswitch ------- OFF
Beat cut SWitCh -++++ reser eee reece eres Position 1 or Normal
@ Standard position of volume control
BASS, TREBLE sotrserettccerceeesavneretenanecnes CENTER
Main Volume adjust ssr+rerssrererree
sete rere 0 dBs output
Test tape for REC/PB ss++rrrrrereeeees Normal tape : UR8
Standard test frequency: ++++srssrersererensererereves 1 kHz
; unless otherwise specified,
Reference input level -----+---+++--++* AUX IN: — 8cBs
Input for REC/PB, Check &measuring ------++-+> AUX IN
~ 28.0 dBs
Output for measuring unless otherwise specified
| UX-A4 B/E/G/GI/EN
: At speaker terminal
@ Test remarks
1. Negative side of the input and output on the testing
set, that ought to be separately to each other, and
then bear in mind there connection the testing set with
2 channeles Electronic voltmeter, the negative side
never connect commonly.
2. Replaced
output load with a dummy and that lead
wire to be used as big as posible.
3. Attach top cover when measuring and connect filter
shown below Fig. 1 to V. meter.
* Load at measured terminal
2
Meter
0.47
OuT
INPUT
GND
Fig. 1
i Measuring condition (Radio section)
Refer to rating SQUICE ts+rretet erences Tuner+B : DC 5.8V
Reference output -+*+*+*+ Speaker : 50mW(0.45 V}/ 4 Q
Headphon : {0.06V)/ 32 2
AM frequency srrrrrrrresereetesees 400Hz modulation 30%
FM frequency vererssrereeereeeereereess
AOOHZ modulation
frequency deviation 22.5kHz
@ Standard position of switches and controllers
FUNCtION*
oot et sete e cette nenscnnennrecseceawnrenrees RADIO
Mode
een ncee mrss scccccnevengacnecncccenocewaeen STEREO
Super bass
POTTRUTITITIT STII TILT TTL
OFF
@ Careful points for adjustment
1. Connect 30 pF capacitor and 33 k Q resistor to the
output side of the IF sweeper in series while 0.082
F capacitor and 100k © resistor to the input side in
series.
2.Set output level of the IF sweeper as minimum
as
adjustable.
3. RF Alignment order
Procedure of the steps of tracking should be kept.
{No. 1890) 39

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