SHARP 37VT-24H Service Manual
SHARP 37VT-24H
General Information
TV VCR Combination
Also Covers
37VT-24S/T
VP-5 Chassis
Remote Control Diagram (37VT-24H)
Remote Control Diagram (37VT-24S/T)
Recommended Safety Parts
Item Part No. Description
V801 VB370BVBK1U-S CRT, 37cm (14”) BX
DY601 RCiLH0057PEZZ R Deflection Yoke BB
L799 RCiLG0048PEZZ Degaussing Coil AL
TU201 VTUOF4EK-724/ UHF Tuner BC (37VT-24H)
TU201 VTUOF4EG-722/ R VHF/UHF Tuner BL (37VT-24S1T)
UNT201 RiFU-0639GEZZ IF-Pack Unit BM (37VT-24H)
UNT201 RiFU-0624GEZZ IF-Pack Unit BB (37VT-24S,T)
R320 RR-XZ0026CEZZ 10 1/4W Fuse Resistor AB
R361 VRG-RL2HB5R6J 5.6 1/2W Fuse Resistor AB
R424 RR-XZ0026CEZZ 10 1/4W Fuse Resistor AB
R7807 VRG-SC2EB1R2J 1.2 1/4W Fuse Resistor AB
R9951 VRG-SC2EB2R2J 2.2 1/4W Fuse Resistor AC
IC702 RH-FX0030CEZZ Photo Coupler PC113L1 AF
IC703 RH-FX0030CEZZ Photo Coupler PC113L1 AF
L702 RCiLF0105CEZZ Line Filter AP
L703 RCiLF0105CEZZ Line Filter AP
T601 RTRNF0120PEZZ Flyback Trans. (FBT) BE
T701 RTRNZ0104PEZZ Power Trans. AW
C702 RC-FZ016SGEZZ 0.47 AC250V Ceramic AK
C703 RC-FZ016SGEZZ 0.47 AC250V Ceramic AK
C725 RC-KZ0023CEZZ 4700p 2kV Ceramic AD (37VT-24S/T)
C726 RC-KZ0023CEZZ 4700p 2kV Ceramic AD (37VT-24S/T)
C727 RC-KZ0128CEZZ 2200p 4kV Ceramic AD (37VT-24H)
R501 RR-XZ0016CEZZ 1 1/2W Fuse Resistor AB
R502 VRG-RF2EB2R2J 2.2 1/4W Fuse Resistor AB
R603 RR-XZ0073CEZZ 270 1/2W Fuse Resistor AB
R612 VRG-RL2HB1R0K 1 1/2W Fuse Resistor AB
R721 VRG-RL2HB3R3J 3.3 1/2W Fuse Resistor AB
R725 VRC-UA2HG825K 8.2M 1/2W Solid AA
R726 VRC-UA2HG825K 8.2M 1/2W Solid AA
F601 QFS-J1023CEZZ Fuse, Circuit Protector AE
F701 QFS-C2026CEZZ Fuse T2AH 250V AE
P701 QPLGN0304CEZZ Plug 3-pin (A) AB
P702 QPLGN0207CEZZ Plug 2-pin (G) AA
S1201 QSW-P0588CEZZ Power Switch AP
SC851 QSOCV0829CEZZ CRT Socket AK
(Cabinet Parts)
7 RCiLG0048PEZZ Degaussing Coil (L799) AL
8 RCiLH0057PEZZ Deflection Yoke (DY601) BB
9 VB370BVBK1U-S Picture Tube (V801) BX
38 QACCB5002PEZZ AC Cord AX (37VT-24H)
39 QACCZ2048CESA AC Cord AR (37VT-2451T)
or
QPLGN0360CEZZ AC
or
QPLGN0260CEZZ AC
Mechanical Parts
Item Part No. Description
1 LBNDK1009AJZZ Tension Band Ass’y AH
2 LBOSZ1001AJZZ Tension Arm Boss AB
3 LBOSZ1002AJZZ Slow Brake Boss AD
4 LBOSZ1003AJZZ Cassette Stay-L AC
5 LCHSM0158AJZZ Main Chassis Assy BA
6 LHLDZ1958AJZZ Loading Motor Block AG
7 LPOLM0056GEZZ Supply Pole Base Ass’y AM
8 LPOLM0057GEZZ Take-up Pole Base Ass’y AM
9 MLEVF04S9AJZZ Take-up Loading Arm Assy AF
10 MLEVF0461AJZZ Supply Loading Arm Ass’y AF
11 MLEVF0463AJZZ Pinch Drive Lever Assy AU
12 MLEVF0464GEZZ Pinch Roller Lever Assy AW
13 Not Used
14 Not Used
15 MLEVF0467AJZZ Tension Arm Assy AK
16 MLEVF0468AJFW Audio/Control Head Arm AG
17 MLEVP0271AJZZ Shifter Drive Lever AE
18 MLEVP0272AJZZ Pinch Double Action Lever AD
19 MLEVP0273AJZZ Reverse Guide Lever Assy AL
20 MLEVP0275AJZZ Reverse Drive Lever AD
21 MLEVP0276AJZZ Slow Brake AE
22 MLEVP0277AJZZ Open Lever AD
23 MLEVP0278AJZZ Clutch Lever AE
24 MLEVP0279AJZZ Supply Main Brake Assy AF
25 MLEVP0280AJZZ Take-up Main Brake Assy AF
26 CLEVP0287AJZZ Auto Head Cleaner Assy AG
27 MSLiP0008AJZZ Shifter AH
28 MSPRC020SAJFJ Audio/Control Head AB Spring, x3
29 MSPRD0165AJFJ Reverse Guide Spring AE
30 MSPRT0402AJFJ Loading Double Action AE Spring, x2
31 MSPRT0403AJFJ Pinch Double Action Spring AD
32 Not Used
33 MSPRT0405AJFJ Tension Spring AE
34 NBLTK0066AJ00 Reel Belt AE
35 NDAiV1070AJ00 Reel Disk, x2 AE
36 NGERH1267AJZZ Loading Connect Gear AD
37 NGERH1268AJ00 Master Cam AE
38 NGERH1269AJZZ Cassette Housing AD Control Drive Gear
39 NGERH1270AJZZ Take-up Loading Gear AF
40 NGERH1271AJZZ Supply Loading Gear AD
41 NGERH1272AJZZ Pinch Drive Cam AE
42 NGERH1275AJZZ Supply Reel Relay Gear AE
43 NGERH1276AJZZ Take-up Reel Relay Gear AE
Mechanical Parts
Item Part No. Description
44 NGERW1062AJZZ Worm Gear AD
45 NGERW1063AJZZ Worm Wheel Gear AD
46 NiDR-0015AJZZ Idler Wheel Assy AK
47 NPLYV0155AJZZ Motor Pulley AB
48 NPLYV0156AJZZ Limiter Pulley Assy AM
49 NROLP0110GEZZ Guide Roller, x2 AH
50 NSFTP0034AJZZ Tension Pole Adjuster AB
51 PGUMM0043AJZZ Damper Rubber AD
52 PREFL1007AJZZ Light Guide AE
53 QCNW-0247AJZZ FFC for Drum Motor AG
54 QCNW-0271AJZZ FFC for Loading Motor AD
55 QCNW-0272AJZZ FFC for Audio/Control Head AF
56 QPWBF5243AJZZ Audio/Control Head PWB AE
57 QSOCN0605REN1 Socket 6-pin AB
58 RHEDT0031AJZZ Full Erase Head AX
59 RHEDU0085GEZZ Audio/Control Head Assy BA
60 RMOTM1062GEZZ Loading Motor AP
61 RMOTN2053GEZZ Capstan Motor BF
62 RMOTP1129GEZZ Drum Drive Motor AX
63 DDRMW0014TEX2 Upper/Lower Drum Assy BP (37VT-24H)
63 DDRMW0014TEX1 Upper/Lower Drum Assy BQ (37VT-245/T)
64 MSPRC0194GEFJ Drum Earth Brush Spring AA
65 QBRSK0034GEZZ Drum Earth Brush AD
66 XBPSD26P05J00 Drum Drive Motor AA Mounting Screw (5W2.6P+5S) x4
67 PGiDC0055GEFW Drum Base AL
1C CABA2372WEV0 Front Cabinet Assy BE (37VT-24H)
1C CABA2371WEV0 Front Cabinet Assy BE (37VT-2451T)
1-1 Not Available Front Cabinet
1-2 CBTN-0228WEV0 Control Button Assy AP (37VT-24H)
1-2 CBTN-0248WEV0 Control Button Assy AP (37VT-24S1T)
1-3 GCOVA0052PESA R/C Cover AC
1-4 HBDGB0014PESB Badge, SHARP AE
1-5 HDECQ0079PESA LED Decoration Plate AD
1-6 HDECQ0092PESA VCR Flap AH
1-7 JBTN-0155PESA Button, Power AC
1-8 JBTN-0225PE5A Button, Eject AD
1-9 JBTN-0229PE5A Button, Control AG
1-10 LX-TZ3004CEFD Screw, x5 AA
1-11 MSPRC0005PEFW Spring, for Power Button AB
1-12 MSPRD0123AJFJ Spring, for VCR Flap AC
1-13 PSPAH0012PE00 Spacer, x2 (37VT-24S/T) AA
1-14 PSPAH0023PE00 Spacer, x2 AB
1-15 PSPAH0026PE00 Spacer, x1 AD
2 LHLDW0003PEKZ Degaussing Coil Holder, x4 AB
3 TCAUA0002PEZZ Chassis Caution AB
4 PMAGF3006CEZZ Purity Magnet AK
5 PSPAG0004PEZZ Wedge (Gum), x3 AB Yoke Positioning
6 QEARC1414PEZZ Wire, Grounding Strap AK
7 RCiLG0048PEZZ Degaussing Coil (L799) AL
8 RCiLH0057PEZZ Deflection Yoke (DY601) BB
9 VB370BVBK1U-S Picture Tube (V801) BX
10 LX-TZ0013PEFD Screw, for CRT, x4 AD
11 LX-TZ3004CEFD Screw, x5 AA
12 LX-TZ3011CEFD Screw, x2 AA
13 VSP0080P-H3WA Speaker (SP301) AM
14 XEBSD30P12000 Screw, x4 AA
15 GCABB2285PEKA Rear Cabinet BA
16 XTASD40P20000 Screw, x11 AA
17 LHLDZ0094PEZZ Sensor Holder, x2 AC
18 LX-HZ3001PEFD Screw, x22 AA
19 XHPSD30P06WS0 Screw, x5 AA
20 LCHSM0064PEZZ R Chassis Frame AP
21 PSLDM0222PEFW Top Shield AR
22 PSLDM0223PEFW Bottom Shield AM
23 PSLDM0205PEFW Head Amp. Shield AF
24 LHLDP1051PEZZ LED Holder AD
25 PSLDM0214PEFW Shield Case AD
26 TLABM1197PEZZ Model Label AD (37VT-24H)
26 TLABM1198PEZZ Model Label AD (37VT-24S)
26 TLABM1199PEZZ Model Label AC (37VT-24T)
27 QSW-F0001PEZZ Rec. Chip Switch AG
28 LHLDW1003PEZZ Wire Holder, x2 AA
29 LHLDZ1759CEKZ H.V. Wire Holder, x1 AB
30 QCNW-2015PEZZ Connecting Wire (K) AH
31 QCNW-2013PEZZ Connecting Wire (H) AF
32 QCNW-2025PEZZ Connecting Wire (S) AG
33 QCNW-2017PEZZ Connecting Wire (RB/RC) AH
34 LHLDW1046PEZZ Wire Holder, x1 AB
35 LHLDW1033CE00 Wire Holder, x2 AA
36 LHLDW1037PEZZ Wire Holder, x1 AB
37 LHLDW1047PEZZ Wire Holder, x4 AB
38 QACCB5002PEZZ AC Cord AX (37VT-24H)
39 QACCZ2048CESA AC Cord AR (37VT-24S/T)
40 Not Used
41 Not Used
42 LHLDW1064PEKZ Wire Holder, x1 AC
43 QCNW-201 9PEZZ Connecting Wire (AA) AM
44 LHLDW1019PEZZ Wire Holder, x2 AB
45 LHLDW1060PEZZ Wire Holder, x1 AA
46 LHLDK0002PEK0 AC Cord Holder AA
47 LANGT0032PEFW Angle, for FBT AG
48 Not Used
49 LCHSM0060PEZZ R Power Frame AM
50 RCORF0031CEZZ R Core, for AC Cord, x1 AM (37VT-24H)
51 RCORF0031CEZZ R Core, x1 AM
52 QANTL0007PEZZ R Loop Antenna AT (37VT-24H)
53 QANTR0018PEZZ R Dipole Antenna AQ (37VT-24SiT)
54 LHLDW1060PEZZ R Wire Holder, x1 AA (37VT-24H)
54 LHLDW1003PEZZ Wire Holder, x1 AA (37VT-24SiT)
55 QPLGJ0113CEZZ Antenna Plug Adaptor AG (37VT-2451T)
SHARP 37VT-24H
Mechanism Parts View
Cassette Housing Parts View
X-Ray Notes
This receiver is designed so that any X-Ray
radiation is kept to an absolute minimum. Since
certain malfunctions or servicing may produce
potentially hazardous radiation with prolonged
exposure at close range, the following precautions should be observed:
1. When repairing the circuit, be sure not to
increase the high voltage to more than 25.3
kV, (at beam 0µA) for the set.
2. To keep the set in a normal operation, be sure
to make it function on 22.0 kV + 1.5 kV - 2.0
kV (at beam 800µA) in the case of the set.
The set has been factory - Adjusted to the
above-mentioned high voltage. If there is a
possibility that the high voltage fluctuates as a
result of the repairs, never forget to check for
such high voltage after the work.
3. Do not substitute a picture tube with unauthorized types and/or brands which may
cause excess X-ray radiation.
Electrical Adjustments
(TV)
• PRECAUTIONS
1. Calling the service mode
1) Place the set in the stand-by mode.
2) Hold down the CH UP key of the set for 3
seconds or longer and at the same time press
the POWER button of the set. Now the set is
in the service mode.
2. Clearing the service mode
1) There are two ways to clear the service
mode. Press the MENU key on the remote
control unit.
2) Or place the set in the stand-by mode again.
3. Display in the service mode
SCREEN/BACKGROUND ADJUSTMENT
Adjusting Conditions
1. Screen Adjustment
1. Receive the “AV-CH” signal. Keep the blue
background off.
2. Reset “Picture adjust” mode to have the PNORM position.
Adjusting Procedures
1. Call the service mode and take the following
step.
• Screen control: Look at the VCJ IC data on
the screen. Adjust the control so that the 9th
figure from left should turn from “1” to “0”.
2. Background Adjustment
1. Receive the “WHITE BALANCE ADJUSTMENT PATTERN” signal.
2. In the video adjust mode, adjust the brightness and contrast.
• Bright portion: 120 nit
• Dark portion: 20 nit
Keep the colour adjusted at “0”.
1. Call the service mode and take the step
below.
• Red intensity:
• Green intensity:
• Blue intensity:
Pick up the service mode numbers “2” and “3”.
Adjust the colour temperature as follows.
37VT-24H:
7500°K (x=0.300 ± 0.015, y=0.310 ± 0.015)
37VT-24S/T:
8950°K (x=0.290 ± 0.015, y=0.284 ± 0.015)
The “CA-100 Minolta CRT Color Analyzer”
should be used as a colour thermometer.
3. Focus Adjustment
1. Receive the “monoscope pattern” signal.
2. Reset the picture adjust mode to have the PNORM position.
1. Adjust the focus control to have the best
focus in the areas between the pattern’s
center and both its ends.
HORIZONTAL VERTICAL CIRCUIT ADJUSTMENT
1. PAL Adjustment
Adjusting Conditions
1. Receive the “PAL monoscope pattern” signal.
2. Reset the picture adjust mode to have the
picture Normal (P-NORM) position.
Figure 1-1.
Figure 2.
Figure 3.
Adjusting Procedures
1. Call the service mode and take the steps
below.
• VERT-AMP (vertical size): Select the service
mode number “4”. Adjust the VERT-AMP to
have 10% overscan.
• VERT-LIN (vertical linearity): Select the
service mode number “5”. Adjust the VERTLIN to have optimum vertical linearity. (See
Figs. 1-1 and 1-2.)
• VERT-POS (vertical center): Select the
service mode number “6”. Adjust the VERTPOS so that the vertical center be at the
center of the screen. (See Fig. 2.)
• HOR-PHASE (horizontal center): Select the
service mode number “7”. Adjust the HORPHASE so that the horizontal center be at the
center of the screen. (See Fig. 3.)
PURITY ADJUSTMENT
Adjusting Conditions
1. Before the purity adjustment, warm up the set
with beam current of more than 400 µA for
longer than 30 minutes.
2. Receive the queen-only signal and adjust the
beam current to about 500 µA.
3. Fully degauss the CRT with the degaussing
coil.
Figure A.
Figure C.
Figure D.
Adjusting Procedures
Notes:
• Static convergence should be roughly
ad]usted.
• The purity magnet should be positioned where
the magnetic field is zero.
Adjustment:
During the adjustment, keep the set facing the
east.
1. Observe the spots “a” and “b” (shown in Fig.
A) with a microscope. Adjust the purity
magnet to have these spots at the specified
landing positions.
2. If the right and left spots are dqually deviated
outwards from their landing positions (shown
in Fig. B), push the deflection yoke forwards
for proper positioning.
3. If both the spots are shifted to the right or left
(shown in Figs. C and D), adjust the opening
angle of the purity magnet for proper positioning.
4. Make sure that the center spot as well as the
right and left spots are in their specified
landing positions. Check the four corners of
the CRT screen. See if all the landing
positions are satisfactory with the Rank “B”
specifications.
5. If any colour other than green appears, pull
the deflection coil backwards. Landing too
outwards: Deflection yoke to push forwards.
Landing too inwards: Deflection coil to pull
backwards.
6. Receive the monoscope pattern signal.
7. Set the raster rotation at “0” position with the
set facing the east.
Adjustment error: 0 ± 2 mm
8. Tighten up the deflection coil screws.
Tightening torque: 11 ± 2 kg
CONVERGENCE ADJUSTMENT
Adjusting Conditions
This adjustment should be performed after the
purity magnet adjustment.
1. Receive the crosshatch pattern signal.
2. Set the brightness and contrast controls to
the 5/10 and 10/10 positions, respectively.
Figure 1-2.
Figure B.
SHARP 37VT-24H
Adjustments Cont’d
Figure a. Figure b.
Figure c. Figure d.
Adjusting Procedures
STATIC CONVERGENCE
1. Adjust the opening angle of the 4-pole
magnet and rotate the magnet to impose the
blue line over the red one.
2. Adjust the opening angle of the 6-pole
magnet and rotate the magnet to impose the
green line over the blue one.
DYNAMIC CONVERGENCE
3. Take the following steps for dynamic convergence at the edges of the CRT screen.
• Convergence in Fig. a: Insert the wedge “a”
in position, and tilt the deflection coil upward
for correct convergence.
• Convergence in Fig. b: Insert the wedges “b”
and “c” in position, and tilt the deflection coil
downward for correct convergence.
• Convergence in Fig. c: Insert the wedge “c”
deeper, and tilt the deflection coil rightward for
correct convergence.
• Convergence in Fig. d: Insert the wedge “b”
deeper, and tilt the deflection coil leftward for
correct convergence.
4. Stick the above wedges on the CRT, and
apply glass tape over them.
5. Apply lacquer to the deflection yoke screw,
the magnet unit (consisting of purity, 4-pole
and 6-pole magnets) and the magnet unit
screw. Finally receive the red-only signal to
make sure there is no mixture with any other
colour. Do the same with the blue-only signal.
Mechanical Adjustments
REMOVAL AND REASSEMBLY OF CASSETTE HOUSING CONTROL ASSEMBLY
• Removal
1. Set the cassette ejected condition in the
cassette eject mode.
2. Unplug the recorder from the main source.
3. Follow the procedures below in the specified
order.
a) Remove the cassette housing installation
screws
b) Slide and pull out the cassette housing
control assembly upward.
Figure 1-1.
• Reassembly
1. Before installation of the cassette housing
control assembly, make a short-circuit
between TP7701 and TP7702, both located
on your side on the main PWB. Plug in the
powercord. The cassette control drive gear
starts and stops just when the big face gear
shows in the mechanism chassis window.
Engage the tooth 2 of the casecon drive gear
with the tooth 3 of the cassette control drive
angle as shown in Fig.1-2, to position the
cassette control on the mechanism chassis.
Figure 1-2.
2. Follow the procedures for removal in the
reverse order.
Notes:
1) In using a magnet screwdriver, be sure to
keep it away from the A/C head, FE (Full
Erase) head, and the drum.
2) In removal and reassembly, take care not to
hit the cassette housing control assembly and
tools against the guide pin, drum, or the like
there about.
3) Load the cassette once onto the cassette
housing control assembly after reassembly.
TO RUN A TAPE WITHOUT THE CASSETTE
HOUSING CONTROL ASSEMBLY
1. Be sure to make a short-circuit between
TP7701 and TP7702, both located at the left
on your side on the main PWB before turning
on the power.
2. Plug in the power cord.
3. Turn on the power switch.
4. Open the lid of a cassette tape by hand.
5. Hold the lid with two pieces of vinyl tape.
6. Set the cassette tape in the mechanism
shassis.
7. Stabilize the cassette tape with a weight
(500g) to prevent floating.
8. Perform running test.
Figure 1-3.
Note:
The weight should not be more than 500g.
REPLACEMENT AND HEIGHT CHECKING
AND ADJUSTMENT OF REEL DISKS
• Removal (Supply and Take-up reel disks)
1. Remove the cassette housing control
assembly.
2. Pull the tension band out of the tension arm.
3. Release the supply/take-up auxiliary brake
lever by hand, which makes unnecessary
removal of the supply main brake and the
take-up main brake.
4. Open the hook at the top of the reel disk, and
remove the reel disk.
<In the EJECT or UL STOP mode>
Figure 1-4.
Note:
When the tension band is pressed in the
direction of the arrow for removal, the catch is
hard to be deformed.
Figure 1-5.
• Reassembly (Supply reel disk)
1. Clean the reel disk shaft and apply oil to it.
2. Align the phase of the reel disk to that of the
reel relay gear, and install a new supply reel
disk onto the shaft.
3. Replace the tension band around the supply
reel disk, and insert it into the hole of the
tension arm with the supply auxiliary brake
lever released.
4. Check the reel disk height.
Notes:
1) Take enough care not to deform the tension
band during installation of the supply reel
disk.
2) Be careful not to damage the supply main
brake and the reel relay gear.
• Reassembly (Take-up reel disk)
1. Clean the reel disk shaft and apply oil to it.
2. Release the take-up auxiliary brake lever to
align the phase of the reel disk to that of the
reel relay gear and to install a new take-up
reel disk onto the shaft.
3. Check the reel disk height and reassemble
the take-up main brake.
Note:
Take care not to damage the take-up main
brake.
* After reassembly, check the video search
rewind back tension, and check the brake
torque.
• Height checking and adjustment
Note:
Place the master plane onto the mechanism
unit, taking care not to hit the drum (see Figure
1-6).
Figure 1-6.
• Check that the reel disk is lower than part A
but higher than part B. If the height is not
correct, readjust the reel disk height by
changing the poly-slider washer under the reel
disk.
Note:
Whenever replacing the reel disk, perform the
height checking and adjustment.
Figure 1-7.
CHECKING AND ADJUSTMENT OF TAKE-UP
TORQUE IN FAST FORWARD MODE
• Remove the cassette housing control
assembly.
• Make a short-circuit between TP7701 and
TP7702, both located at the left on your side
on the main PWB. Now plug in the AC cord.
• Setting
1. Set a torque gauge to zero on the scale.
Place it on the take-up reel disk.
2. Press the FF button to set the mechanism to
the fast forward mode.
3. To calculate the remaining capacity of the
play back mode, slowly rotate the supply reel
disk, and then shift it into the forward mode.
• Checking
1. Turn the torque gauge slowly (one rotation
every 2 to 3 seconds) by hand in the take-up
direction.
2. Check to see if the take-up torque is higher
than 69 mN•m (700 gf•cm).
Figure 1-8.
• Adjustment
1. If the take-up torque is outside the range,
clean the capstan D.D. motor pulley, drive
belt and limiter pulley with cleaning liquid,
then recheck the torque.
2. If the take-up torque is still out of range,
replace the drive belt.
Notes:
1. Hold down the torque gauge so that it may
not fly off.
2. When checking thetake-uptorque, do not
keepthe reel disk locked for a longer time.
CHECKING AND ADJUSTMENT OF TAKE-UP
TORQUE IN REWIND MODE
• Remove the cassette housing control
assembly.
• Makes short-circuit between TP7701 and
TP7702, both located at the left on your side
on the main PWB. Now plug in the AC cord.
• Setting
1. Set a torque gauge to zero on the scale.
Place it on the supply reel disk.
2. Press the REW button to set the mechanism
to the rewind mode.
3. To calculate the remaining capacity, slowly
rotate the take-up reel disk, and then shift it
into the rewind mode.
• Checking
1. Turn the torque gauge slowly (one rotation
every 2 to 3 seconds) by hand in the take-up
direction.
2. Check to see if the take-up torque is higher
than 69 mN•m (700 gf•cm).
Figure 1-9.
• Adjustment
1. If the take-up torque is outside the range,
clean the capstan D.D. motor pulley, drive belt
and limiter pulley with cleaning liquid, then
recheck the torque.
2. If the take-up torque is still out of range,
replace the drive belt.
Notes:
1. Hold down the torque gauge so that it may
not fly off.
2. When checking the take-up torque, do not
keep the reel disk locked for a longer time.
CHECKING AND ADJUSTMENT OF TAKE-UP
TORQUE IN PLAYBACK MODE
1. Remove the cassette housing control
assembly.
2. Make a short-circuit between TP7701 and
TP7702, both located at the left on your side
on the main PWB. Now plug in the AC cord.
3. Open the lid of the cassette torque meter, and
hold it with two pieces of vinyl tape.
4. Load the cassette torque meter into the unit.
5. Put the weight (500g) on the cassette torque
meter.
6. Press the REC button to put the unit in REC
mode.
Set value LP10.5 ± 3.8mNm (107 ± 39gf.cm)
* SP only model 37VT-24S/T:
12.0 ± 3.8mN•m (122 ± 39gf.cm)
Figure 1-10.
• Checking
1. Check that the torque is in the range of 10.5 ±
3.8mN•m (107 ± 39gf•cm).
2. The torque fluctuates due to the rotational
deviation of the limiter pulley ass’y. Use the
center of the fluctuation as the value.
3. Place the assy in the LP record mode, and
check that the take-up torque is within the
range.
• Adjustment
If the take-up torque in the playback mode is
outside the range, replace the limiter pulley
ass’y.
SHARP 37VT-24H
Adjustments Cont’d
Note:
Stabilize the cassette torque meter to prevent
floating.
CHECKING AND ADJUSTMENT OF TAKE-UP
TORQUE IN VIDEO SEARCH REWIND MODE
• Remove the cassette housing control
assembly.
• Make a short-circuit between TP7701 and
TP7702, both located at the left on your side
on the main PWB. Now plug in the AC cord.
• Setting
1. Push the PLAY button to place the assy in the
playback mode.
2. Push the REW button to place the assy in the
video search rewind mode.
• Checking
1. Place the torque gauge on the supply reel
disk, and turn it counterclockwise very slowly
(one rotation every 1 to 2 seconds) and check
that the torque is within the set value 14.0 ±
3.9mN•m (144 ± 40gf•cm.)
Figure 1-11.
Note:
Set the torque gauge securely on the supply
reel disk. If it is not secure, the measurement
will be incorrect.
• Adjustment
If the take-up torque in video search rewind
mode is outside the range, replace the limiter
pulley ass’y.
Note:
The torque fluctuates due to the rotational
deviation of the limiter pulley ass’y. Use the
center of the fluctuation at the value.
CHECKING THE VIDEO SEARCH REWIND
BACK TENSION
• Remove the cassette housing control
assembly.
• Make a short-circuit between TP7701 and
TP7702, both located at the left on your side
on the main PWB. Now plug In the AC cord.
• Checking
1. Push the PLAY button to place the ass’y in
the playback mode.
2. Push the rewind button to place the ass’y in
the video search rewind mode.
3. Place the torque gauge on the take-up reel
disk, and turn it counterclockwise very slowly
(one rotation every 2 to 3 seconds) and check
that the torque is within the set value
2.7±1mN•m (28±10gf•cm).
Figure 1-12.
Notes:
1) Set the torque gauge securely on the take-up
reel disk. If it is not secure, the measurement
will be incorrect.
2) Measure the torque applying the torque
gauge’s weight.
CHECKING THE PINCH ROLLER PRESSURE
• Remove the cassette housing control
assembly.
• Make a short-circuit between TP7701 and
TP7702, both located at the left on your side
on the main PWB. Now plug in the AC cord.
• Checking
Push the PLAY button to place the ass’y in the
playback mode.
Figure 1-13.
1. Detach the pinch roller from the capstan
shaft.
2. Set the tension gauge by hooking the tension
gauge adapter onto the pinch roller shaft.
3. Gradually release the pressure to allow the
pinch roller to touch the capstan shaft. When
the pinch roller just touches the capstan shaft,
read the indication on the gauge.
4. Check that the reading of the tension gauge
is in the range of 900 to 1200g.
CHECKING AND ADJUSTMENT OF TENSION
POLE POSITION
• Remove the cassette housing control
assembly.
• Make a short-circuit between TP7701 and
TP7702, both located at the left on your side
on the main PWB. Now plug in the AC cord.
• Setting
1. Open the lid of cassette tape (E-180), and
hold it with two pieces of vinyl tape.
2. Load the cassette tape into the unit.
3. Put the weight (500g) on the cassette tape.
4. Make the adjustment with the beginning of a
E-180 tape.
Figure 1-14.
• Checking
1. Set a cassette tape, press the REC button
and get the tape loaded. Now check the
tension pole position.
2. Visually check to see if the center of the
tension pole is in alignment with the line 1.3
mm left of the center line of the sup guide
shaft. Readjust as required in the following
steps.
Figure 1-15.
1) If the center of tension pole is at the left from
the dotted line:
Figure 1-16.
Put a bladed screwdriver into the tension pole
adjuster and turn it clockwise.
2) If the end is at the right from the dotted line:
Figure 1-17.
Put a bladed screwdriver into the tension pole
adjuster to turn it counter-clockwise.
Adjustable range of the tension pole adjuster.
3) Adjustable range of tension pole adjusting
cam.
Figure 1-18.
Adjust the tension pole adjuster so that the
circle mark on the cam be within 90° left and
right.
CHECKING AND ADJUSTMENT OF RECORD/
PLAYBACK BACK TENSION
• Remove the cassette housing control
assembly.
• Make a short-circuit between TP7701 and
TP7702, both located at the left on your side
on the main PWB. Now plug in the AC cord.
• Setting
1. Open the lid of cassette torque meter, and
hold it with two pieces of vinyl tape.
2. Load the cassette torque meter into the unit.
3. Put the weight (500g) on the cassette torque
meter.
Figure 1-19.
• Checking
1. Push the REC button to place the unit in the
record mode.
2. Check that the back tension indicated by the
gauge is within the set range 31 to 38 g.cm.
Notes:
1. Make sure that the video cassette tape is
over the retaining guide.
2. Make sure that the tape is not slack or
damaged at either end.
• Adjustment
1. If the reading of the cassette torque meter is
less than specified, move the tension spring
hook towards A.
2. If the reading of the cassette torque meter is
more than specified, move the tension spring
hook towards B.
Figure 1-20.
CHECKING THE BRAKE TORQUE
• Checking the brake torque at the supply
side
Figure 1-21.
• Remove the cassette housing control
assembly.
• Make a short-circuit between TP7701 and
TP7702, both located at the left on your side
on the main PWB. Now plug in the AC cord.
• Setting
1. Set a torque gauge to zero on the scale.
Place it on the supply reel disk.
2. Switch from the FF mode to the STOP mode.
3. Disconnect the AC power plug.
• Checking
1. Rotate the torque gauge (approx. one
revolution per 2 seconds) in the clockwise
(CW) direction and counterclockwise (CCW)
direction of the supply brake so that the reel
disk and the indicator of the torque gauge
rotate at an equal rate.
Check that the values are within the range of
CW direction
= 10 ~ 32mN•m (100~330gf•cm), CCW direction
= 5.9 ~ 9.8mN•m (60-100gf•cm), and that the
brake torque in the CW direction is at least twice
as high as that in the CCW direction.
• Checking the brake torque at the take-up
side
Figure 1-22.
• Remove the cassette housing control
assembly.
• Make a short-circuit between TP7701 and
TP7702, both located at the left on your side
on the main PWB. Now plug in the AC cord.
• Setting
1. Set a torque gauge to zero on the scale.
Place it on the take-up reel disk.
2. Switch from the FF mode to the STOP mode.
3. Disconnect the AC power plug.
• Checking
1. Rotate the torque gauge (approx. one
revolution per 2 seconds) in the clockwise
(CW) direction and counterclockwise (CCW)
direction of the take-up brake so that the reel
disk and the indicator of the torque gauge
rotate at an equal rate. Check that the values
are within the range of CCW direction = 9.8 ~
34mN•m (100 ~ 340gf•cm), CW direction = 4
~ 8.3mN•m (40 ~ 85gf•cm), and that the brake
torque in the CCW direction is at least twice
as high as that in the CW direction.
• Adjustment of the brake torque at the
supply side and the take-up side
1. If the supply or take-up brake torque is
outside the range, clean the supply or take-up
reel disk brake lever pad, then recheck the
torque.
2. If the supply or take-up brake torque is still
outside the range, replace the main brake
assy.
Note:
When the main brake is replaced, perform the
height checking and adjustment of reel disks,
and the brake torque checking.
REPLACEMENT OF AC (Audio/Control)
HEAD
1. Remove the cassette housing control
assembly.
2. Place the unit in the unloading mode, and
unplug the power cord.
• Removal
1. Remove the screw (A)(B)(C)(1)(2).
2. Unsolder the A/C head PWB soldered to the
A/C head assembly.
Notes:
1. After replacement, be sure to perform the
adjustment of the tape drive train. Under any
circumstances, avoid touching the head.
Clean the head, if touched with your finger,
with alcohol.
2. Take care that the springs do not fly off when
removing the screws (A)(B)(C).
Figure 1-23.
SHARP 37VT-24H
Adjustments Cont’d
• Replacement
1. Solder the removed A/C head PWB onto a
new A/C head assembly.
2. Using the slide calipers, set 10.3 mm for the
height of the A/C head arm (bottom surface)
to the A/C head plate (screw area). (3 places)
Solder (See figure.)
Figure 1-24.
3. Align the left and of the gear of the NC head
arm to the mark on the chassis, and temporarily tighten the screws (1) and (2) to allow
the A/C head arm to smoothly move. (Reference: Temporary tightening torque: 0.2 N.m
as preferable)
Figure 1-25.
Note:
Take care that he adjustment or height of the A/
C head may vary during final tightening if the
screws (1) or (2) is temporarily tightened to be
loose.
[A/C head height rough adjustment]
• Setting
Figure 1-26.
1) Set the cassette tape to the mechanism
chassis.
2) Press the PLAY button to the put the unit in
the playback mode.
3) Roughly adjust the height of the A/C head by
turning the screw (C) until the tape is in the
position shown.
Figure 1-27.
• Adjustment
Adjust the screw (C) visually so that the control
head is visible 0.3 to 0.5mm below the bottom of
the tape.
HEIGHT ADJUSTMENT OF REVERSE GUIDE
[Height adjustment of reverse guide]
Figure 1-28.
1) Remove open lever (Figure 1-29 (a)).
2) In the tape load mode, make adjustment at
the 13.38mm side first and then rotate the
reverse guide adjuster nut by 1/10 turn
counterclockwise.
3) Actually load the unit with a tape, put it in the
play mode, and make sure the tape is free
from wrinkles near the reverse guide.
4) Use a commercially available box driver to
turn the height adjusting nut.
Figure 1-29 (a).
Figure 1-29 (b).
ADJUSTMENT OF TAPE DRIVE TRAIN
1. Remove the cassette housing control
assembly.
2. Make a short-circuit between TP7701 and
TP7702, both located on the main PWB. Now
turn on the power.
3. Check and adjust the position of the tension
pole.
4. Check and adjust the video search rewind
back tension.
5. Set the A/C head.
6. Rough adjustment of tape drive train.
a) Connect the oscilloscope to the test point for
PB CHROMA envelope output (TP3301). Set
the synchronism of the oscilloscope to EXT.
The PB CHROMA signal is to be triggered by
the head switching pulse (TP3302).
b) Loosen the setscrew at the lower part of the
guide roller, and adjust it with an adjusting
Hex Wrench (JiGHW0009) so that the guide
roller turns smoothly. (Do not overloosen the
set screw, which causes insecurity of the
guide roller.) (See Figure 1-30.)
c) Set the alignment tape (monoscope pattern)
on the reel disk, and place the unit in the
playback mode. (Place a 500 g weight on the
cassette tape to prevent floating of the
cassette tape.)
Figure 1-30.
Figure 1-31.
d) In the X value adjustment mode (see the
Electrical Adjustment), change the envelope
waveform from MAX to MIN, and MIN to MAX
by pushing the (+) or (-) tracking button, and
check a flat response is obtained on the
waveform.
e) If a flat response cannot be obtained, roughly
adjust the guide rollers on the supply side and
take-up side using an adjusting screw driver
until a flat response can be obtained.
f) Tighten the screw (A) to eliminate wrinkles
from the tape of the retain guide flange area.
Replace the tape to check the tape on the
retain guide flange area for wrinkles.
1) No wrinkle is present.
Turn the screw (A) clockwise to generate
wrinkles on the tape at the flange area, and
then back off the screw (A) as far as the
wrinkles are just eliminated.
2) Wrinkles are present.
Turn the screw (A) counterclockwise as far as
the wrinkles are just eliminated.
Reference:
If the screw (A) is turned clockwise, wrinkles
will be produced on the lower flange.
Notes:
1. Place the tracking control in the center
position, and adjust the X-position so that the
PB CHROMA envelope becomes maximum
for easier rough adjustment of the tape drive
train.
2. In the rough adjustment, pay particular
attention to the outlet side.
Figure 1-32.
Figure 1-33.
Figure 1-34.
7. Adjustment of A/C head height and
azimuth
a) Connect an oscilloscope to the audio output
terminal.
b) Using the alignment tape with linear audio
pre-recorded signal of 1 kHz, adjust the
screws (B) and (C) to maximize the audio
output, and adjust the screw (A) to eliminate
wrinkles from the tape at the retain guide
flange. (Refer to 31-6-f.) Repeatedly adjust
the screws (B), (C) and (A) in this sequence
until the audio output becomes the maximum.
(1 to 3 times as ordinary)
c) Using the alignment tape which records a
linear audio signal of 6 kHz, finally adjust the
screw (B) until the audio output becomes the
maximum.
Note:
Figure 1-35.
The screws (A), (B) and (C) in the Figure 1-26.
8. Adjustment of tape drive train and XPosition
(Use the “VROUBZFS” alignment tape for 37VT24H)
a) Connect the oscilloscope to the test points
(TP3301) for PB CHROMA envelope output.
Set the synchronism of the oscilloscope to
EXT. The PB CHROMA signal is to be
triggered by the head switching pulse
(TP3302).
b) Play back the tape drive train alignment tape.
c) Push the (+) or (-) button to change the
envelope waveform from MAX to MIN, and
MIN to MAX. Adjust the guide roller’s height
on the supply and take-up sides with an
adjusting screw driver, to obtain an envelope
waveform that is as flat as possible.
d) If the tape is above or below the helical lead,
the PB CHROMA waveform will take the
shape shown in Figure 1-35.
e) Adjust for maximum flatness of the envelope.
f) Push the (+) or (-) tracking button to check
that a flat response is obtained on the
envelope waveform.
g) Secure the guide roller by tightening the
guide roller setscrew in the unloading mode.
h) Play back the tape drive train alignment tape
to check that the envelope waveform does not
change.
9. Adjustment of A/C head X-position.
a) In the X value adjustment mode (see the
Electrical Adjustment), make a short-circuit
between TP7701 and TP7702, both located at
the left on your side on the main PWB, to
center the tracking.
b) Move the A/C head arm with an adjusting
gear driver and adjust the A/C head position
for maximum head switching pulse low side
envelope. Finally tighten the screws (1) and
(2) in that order (Figure 1-23). (Reference:
Final tightening torque: 0.6 N.m is preferable.)
c) Adjust the playback head switching point.
d) Check the flatness of the envelope waveform
and sound by playing back a recorded tape.
Figure 1-36.
REPLACEMENT OF THE CAPSTAN D.D.
(DIRECT DRIVE) MOTOR
• Remove the cassette housing control
assembly.
• Removal (Follow the order of indicated
numbers.)
1. Disconnect from the board-to-board connector on the main PWB.
2. Remove the drive belt (1).
3. Remove the screws (2)
Figure 1-37.
• Reassembly
1. Mount the capstan motor on the mechanism
chassis making sure not to allow the capstan
shaft to hit the mechanism chassis, and
attach it with the three screws.
2. Attach the reel belt. Reconnect to the boardto board connector on the main PWB.
Notes:
1. After installing the capstan D.D. motor, be
sure to rotate the capstan D.D. motor and
check the movement.
2. Check the servo circuit.
REPLACEMENT OF DRUM D.D. MOTOR
1. Put the unit in the cassette eject position.
2. Unplug the power cord.
• Removal (Reverse the order in reassembly.)
1. Disconnect the FFC cable (1).
2. Unscrew the D.D. stator assembly fixing
screws (2).
3. Take out the D.D. stator assembly (3).
4. Unscrew the D.D. rotor assembly fixing
screws (4).
5. Take out the D.D. rotor assembly (5).
Notes:
1. In removing the D.D. stator assembly, part of
the drum earth spring pops out of the pre-load
collar. Be careful not to lose it.
2. Secure the D.D. rotor assembly so that the
installation positioning holes in the D.D. rotor
assembly and upper drum assembly match.
(Match the upper drums notch with the rotors
hole.)
3. Be careful not to damage the upper drum or
the video head.
4. Be sure that the hall device and the D.D.
stator assembly are not damaged by the D.D.
rotor assembly or other parts.
5. After installation, adjust the playback head
switching point.
SHARP 37VT-24H
Adjustments Cont’d
Figure 1-38
ASSEMBLE THE MECHANISM’S PARTS
REQUIRING THE PHASE MATCHING IN THE
STEPS BELOW.
1. Assembling the pinch roller assembly, reverse
guide assembly and the pinch drive cam (on
the front of the mechanism chassis).
2. Mounting the shifter (on the back of the
mechanism chassis).
3. Mounting the master cam (on the back of the
mechanism chassis).
4. Mounting the connection gear, slow brake
and loading motor assemblies (on the back of
the mechanism chassis).
Figure 1-40-1.
3) Insert Pinch Roller/Pinch Double Action Lever
Ass’y.
2. Mounting the shifter (on the back of the
mechanism chassis).
1. Make sure that the loading gear is at the point
(1) as shown.
2. Place the shifter in position, keeping in mind
the 6 insertion points and the three relief
points.
3. For the phase matching at the insertion point
(1) see the point (2) as shown.
4. Finally fix the shifter with two washers located
on insert points (1) and (4).
Figure 1-41.
3. Mounting the master cam (on the back of
the mechanism chassis).
1) Make sure beforehand that the shifter is at
the point as shown.
2) Place the master cam in the position as
shown.
Note:
See the figure below for the phase matching
between the master cam and the cassette
control drive gear.
3) Finally fix the master cam with E-ring.
• Replacement
1) Take out the old loading motor. Place a
replacement loading motor as shown above
(Figure 1-44.).
Figure 1-45.
Press-fit the loading motor pulley with a force of
less than 98N (10 kgf). Be sure that the pulley is
7.7 mm away from the motor.
ASSEMBLY OF CASSETTE HOUSING
1) Frame-R ass’y
Figure 1-43.
REPLACEMENT OF LOADING MOTOR
• Removal
Remove 2 screws.
1. Assembling the pinch roller assembly, reverse
guide assembly and the pinch drive cam (on
the front of the mechanism chassis).
Place the following parts in position in numerical
order.
1) Reverse drive lever (1).
2) Reverse guide spring (2).
3) Reverse guide lever ass’y (3).
4) R/G adjusting nut (4).
5) Pinch drive cam (5).
6) Pinch roller ass’y (6).
7) Open lever (7).
Figure 1-46.
2) Synchro Gear, Drive Gear L and Drive Gear R
Figure 1-40-2.
4) Insert Open Lever.
Figure 1-39.
Figure 1-40-3.
Figure 1-42.
Figure 1-47.
Figure 1-44.
Figure 1-48.
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