JVC CX-F5K User manual

JVC
MODEL CX-F5K, CX-5K
8 For specifications,dimensions and weights of these models, refer to the Instruction Book herewith
attachedtothis ServiceManual.
Contents
Location of Main Parts . . . . . . . . . . . . . . . . . . . . . . . .2
Removal of Main Parts . . . . . . . . . . . . . . . . . . . . . . . .3
Positioning of the pointer . . . . . . . . . . . . . . . . . . . . . . 4
Service and check method. . . . . . . . . . . . . . . . . . . . 5
Main Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Parts Arrangement for Alignment . . . . . . . . . . . . . . . .8
Standard Schematic Diagram of CX-5K. . . . . . . . . . . . 9
Standard Schematic Diagram of CX-F5K
(Amplifire section).
. . . . . . . . . . . . . . . . . . . . . . . . . . 10
Standard Schematic Diagram of CX-F5K
(Tuner section)
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
P. C. Board Parts (MainBoard of CX-5K) . . . . . . . . . 12
P. C. Board Parts (Main Board of CX-F5K). . . . . . . . . 13
P. C. Board Parts (Governer Board) . . . . . . . . . . . . . . 14
P. C. Board Parts List (Main Board of CX-5K) . . . . . . 14
P. C. Board Parts List (Main Boardof CX-F5K) . . . . . 15
Exploved view of Mechanism 18
Assembly and Parts List.
. . . . . . . . . . .. . . . . . . . . . 17
Exploved view of Enclosure Assembly and Parts List . . 18
Packing and Packing Parts List . . . . . . . . . . . . . . . . . 21
Accessories
. . . . . . . . . . . . . . . . . . . . . . . . . Back Cover
No. 1665
Novern
ber 1985

Location of Main Parts(~echanisrn section)
Top View
ldler Gear(R)
ldler Gear(F)
Motor
Main puly
Sub chassis
I I
Bottom View
Capstan Motor
1 Belt
1
Pinch Roller
I I
Arimus Adj ~ckew I
P. B Head
I ~ituatorBraeket
Pinch Roller(FWD)
Elrevtor
I Reel unit
~ctuatbrMotor
I
I
Main Pulley
I
Flywheel(REV)
Flywheel(FWD)
2 (No. 1665)

Removal of Main Parts
Note:This unitcan easily be damaged by incorrect servicing
due to
its compact size. To avoid this, classify the
mountingscrews in removal.
Lid Ass'y
1. Remove the slide knobof the REVERSE MODE switch.
2. Remove three screws @ secured from the front, two
screws
@ on both sides and three screws @ secured
from theinside.
(Theazimuth can be adjusted in this condition.)
Note:When assembling the lid ass'y, confirm that there is
no deformation of the contacts on the PWBs in the
mechanism operation section.
BottomCover
1. Remove the eject knob by holding it up and pushing it
out.
2. Remove two screws 13 fixing the bottom cover from
bothsides.
3. Remove a screw @ fixing the middle of the name
plate.
4. Removea screw @.
5. Removethe bottom cover from the reverse side.
Inner Liner
Remove four screws @, @ and @.
Note:Too much pressure will break the flexible PWB; it
requires very careful handling.
(No. 1665)
3

Boardsand Mechanism
1. Remove twoscrews 11 fixing the main PWB on the lid
side and twoscrews
12 fixing the contact PWB.
2. Remove twoscrews 13 fixing the PWB on the bottom.
tact PWB.
8
Note:The spring can be removed by removing the con-
3. To remove the chassis, remove three screws '@ and
8.
4. ~fterthe above procedure, it can be seen that the actu-
ator motor of mechanism and the head ere soldered to
the main PWB and the capstan motor and the wire of
the
@ side of the battery are soldered to the governor
PWB.
MechanismAss'y
1. Remove the head lead and the wire of the actuator
motor from the main PWB.
2. Remove the wire of the capstan motor and wires, etc.
connectedto the main PWB.
Positioning of the pointer
SPSJ1735N
L?
Adjustment of
Pointer Position
4 (No. 1665)

Service and check method
Note: When disassembled, the CX-F5/CX-5 cannot be
operated normally, so check as described below.
1. Explodedview
(This illustration shows the mechanism ass'y set up verti-
cally. Inorder to
set it up vertically, removethe governor
P.C.B. from the chassis.)
2. Check procedure
1) Disassemble as shown in Fig. 1. (The unit does not
operate inthis condition.)
2) Solder the wires at points
@ to @ where thewires
go out. (Avoid re-solderingafter this as itwill cause a
malfunctionafter assembly.)
3) Connect Q306 collector and GND by soldering in a
wire. (Sinceremovingthe governor P.C.B. causes auto
stop to operate, this
is defeated by the wire.)
. ~
1) Connect wires @, @ and @ andwire @ .
2) Position the slide switch of the governor P.C.B. tothe
switch arm position of the mechanism ass'y.
3) Temporarily connect the PLAY/DIRECTlON button
and point
@ with awire.
* After the above procedure, itis possible todo normal
operations.
4. Operation modes
Terminal
Notes:
"-" indicatesopen.
"L" indicatesthat it is grounded (point
@ ).
"H" indicates open with B+ supplied from the
mechanism control IC.
Main Board
I
Collector
Q30,k
E
PLAY/DIRECTION STOP
Mecha Ass'y
(No. 1665) 5

Main Adjustments
CASSETTE ADJUSTMENTS
Conditions Power supply : DC 1.5 V
Output
: Load impedanceof 16 Cl at headphonesterminals
I Tape tobe used 1
Items Adjustment procedure
1.
frequency
response check
2.
sensitivity
adjustment
Azimuth
adjustment
Tape speed
adjustment and
wow
& flutter
check
VTT736
I follows with respectto 1 kHz.
Test tape
VTT702 (8kHz)
Test tape
VTT712 (3kHz)
Test tape
I (Normal) 125 Hz : -2 dB f 3 dB
Play back the
test tape in the FWD and REV
modes and adjust to the mid-point of both
peak levels.
(Apply locking compoundafter adjustment.)
Play back the test tape and adjust the tape
speed so that the counter readingis 3010 Hz
inthe FWD PLAY mode and 2955-3075 Hz
in the REV mode.
Wow
& flutter should be within 0.5% (JIS
RMS).
The playback output level should be
as
(Metal) 8kHz:-4dBf3dB
Test tape Play back the test tape and adjust so that the
VTT724 (1kHz) output of PB GAIN TP is -25 dB f 1dB in
the FWD PLAY mode for both L and R
i
Auto stop level
*
Playback Test tape
adjustment
output check
channels.
VTT662 The output
at the headphoneterminalshould
be 5 mW (0.28 Vl16
Cl) at 1 % distortion.
The level difference between L and R chan-
nels should be within 3 dB.
Apply 2.8Vto
+2.2 V line and adjust VR303
so that TP (Q309E) is high (approx. 1.5 V)
and low when the black and white sections
of idler gear F are placed to cover the photo-
coupler. Perform the high and low checking
with the governor PWB installed in the
mechanism.
Select switch
TAPE 70 ps
I -
Adjustment points
TAPE VR302 on the
governor PWB
6 (No. 1665)
TAPE 120ps
TAPE 70ps
TAPE 70ps
-
Increase 2 dB when
the up points are
short-circuited.
Decrease 2dB when
the down points are
open.
-

TUNER ADJUSTMENTS (CX-F5K/G)
Conditions Power supply
: DC 1.5 V
Volume control
: Set to maximum. (However, set to minimumduring IF adjustments.)
Output measurement point
: Headphone, output level of 56.6 mV/16 R
Bandselect switch : Set to RADIO
Tuning voltage adjustment
Connect the voltmeter to the governor PWB and adjust by fully turning VR2 (Tuning) to the L direction so that the voltage
between TP8 and TP2 (GND) is 1.5f0.1V.
AM IF adjustments
Band select switch : Set toAM.
Position of VR2
: Near the minimum voltage (Low) position with no input signal.
Input
: From TP3 terminal
I Input signal I Adjustment points I Output measurementpoints 1 Adjustment procedure I
(om IF synchro-( T3, T4 I connect TP~ (hotside) -TP2 sid side) to [Set the output to maximurn and
scope (450kHz)
1 OUT the synchroscope. waveforms on right and left sym- metrical.
AM R F adjustments
Input : Standard loopantenna, SSG modulationoutput of 400 Hz, 30%
I Items I lnputfrequency I Adjustment points
I
Positionof VR2 I Adjustment procedure
I
1
2
FM IF and detector adjustments
3
4
5
6
Bandselect switch
: Set to FM.
Position of VR2
: Near the maximum voltage (HIGHfrequency) position with no input signal.
lnput
: From TP4 terminal
520 kHz
1650kHz
I Input signal I ~djustmitpoints 1 Output measurementpoints 1 Adjustment procedLe I
Perform adjustment by repeatingitems 1and 2.
1 From IFsynchro-( TI + T2 I Connect IFOUT to the synchroscope. I Set the band select switch to FM. (
L4
TC4
scope (450kHz)
I OUT
Set the output to maximum.
Make the left and right partsof the
Scurve symmetrical by rotating T2.
Maximum voltage (HIGHfrequency)
Minimum voltage (LOW frequency)
Perform adjustment by repeating items 4 and 5.
Adjust so that 620kHz signal
is received.
Adjust so that 1400kHzsignal
is received.
620 kHz
1400kHz
(No. 1665)
7
Adjust tothe required frequency.
L15
L3

FM RF and MPX adjustments
Input : From rodantennaterminal (TP1)and ground (TP5) Band select switch
: Set to FM.
FM SSG output
: 400 Hz, 30%(22.5 kHz DEV.) FM mode
: Set toSTEREO.
Output impedance
: 75 R unbalanced
Parts Arrangement for Alignment
Main P. W. Board
Adjustment points Positionof VR2
Items
1
2
TUNING
Adjustment procedure
Inputfrequency
L2
TC2
88 MHz
109 MHz
Governer P. W. Board
3
4
5
lAPE SPEED
Minimum voltage (LOWfrequency)
Maximum voltage (HIGHfrequency)
8 (No. 1665)
Adjust to the required frequency.
Perform adjustment by repeatingitems 1and 2.
Set the output to maximum.
Adjust to76 kHz.
Connect TP6
- TP2 (GND)to the
counter.
Adjust so that 90 MHz signal
is received.
90 MHz L1
VR1