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SERVICE MANUAL
No. 82884
July 2001
HR-S6850MS/S7850MS/S7851MS/S8850MS
CARACTÉRISTIQUES TECHNIQUES (The specifications shown pertain specifically to the model HR-S8850MS)
MAGNETOSCOPE
Printed in Japan
VICTOR COMPANY OF JAPAN, LIMITED
VIDEO DIVISION
S40894
This service manual is printed on 100% recycled paper.
COPYRIGHT © 2001 VICTOR COMPANY OF JAPAN, LTD.
HR-S6850MS/S7850MS/S7851MS/S8850MS
No.
82884
INSERT
A.DUB
GÉNÉRALES
Alimentation
: CA 220 V ­ 240 V ` , 50 Hz/60 Hz
Consommation
Alimentation en marche : 22 W
Alimentation en veille
: 3,8 W
Températures
Fonctionnement
: 5°C à 40°C
Stockage
: -20°C à 60°C
Position de fonctionnement
: Seulement horizontale
Dimensions (LxHxP)
: 400 mm x 94 mm x 278 mm
Poids
: 3,7 kg
Format
: Standard S-VHS/VHS PAL/SECAM
Largeur de bande
: 12,65 mm
Vitesse de bande
(VN)
: 23,39 mm/s
(LD)
: 11,70 mm/s
(EP)*
: 7,80 mm/s
Durée maximale d'enregistrement
(VN)
: 240 mn avec une cassette vidéo E-240
(LD)
: 480 mn avec une cassette vidéo E-240
(EP)*
: 720 mn avec une cassette vidéo E-240
*
Signaux PAL seulement
VIDÉO/AUDIO
Système de signal
: Signaux couleur PAL/SECAM et signal
monochrome CCIR, 625 lignes/50 trames
Système d'enregistrement : Balayage hélicoïdal DA4 (Double Azimuth)
Entrée
: 0,5 Vcc à 2,0 Vcc, 75 ohms, asymétrique
Sortie
: 1,0 Vcc, 75 ohms, asymétrique
Rapport signal/bruit
: 45 dB
Résolution horizontale : 400 lignes (S-VHS-PAL, VN/LD)
250 lignes (VHS-PAL, VN/LD)
350 lignes (S-VHS-PAL, EP)
220 lignes (VHS-PAL, EP)
240 lignes (VHS-SECAM, VN/LD)
Gamme de fréquence
: 70 Hz à 10.000 Hz (Audio normal)
20 Hz à 20.000 Hz (Audio Hi-Fi)
Entrée/sortie
: Connecteurs péritélévision à 21 broches:
ENTREE/SORTIE x 1, ENTREE/DECODEUR x 1
Connecteurs RCA:
ENTREE VIDEO x 1, ENTREE AUDIO x 1,
SORTIE AUDIO x 1
Connecteurs S-Vidéo: ENTREE x 1, SORTIE x 1
SYNTONISEUR
Système de syntonisation
: Syntoniseur à synthèse de fréquence
Capacité de canaux TV
: 99 positions (+ position AUX)
Canaux couverts
MINUTERIE
Référence de l'horloge
: Par quartz
Capacité de programmation : Minuterie sur 1 an/8 programmes
Durée de soutien mémoire : 10 mn
ACCESSOIRES
Accessoires fournis
: Câble RF,
Câble péritélévision à 21 broches,
Contrôleur satellite,
Boîtier de télécommande à infrarouge,
Pile "R6" x 2
ATTENTION:
Ce magnétoscope contient des microprocesseurs. Des bruits électroniques
externes ou des interférences peuvent causer un mauvais fonctionnement.
Dans de tels cas, couper l'alimentation et débrancher le cordon
d'alimentation. Puis le rebrancher et remettre l'alimentation. Sortir la cassette.
Après contrôle de la cassette, faire fonctionner l'appareil comme d'ordinaire.
Les caractéristiques techniques sont pour le mode VN à moins
d'indication contraire.
Présentation et caractéristiques modifiables sans préavis.
Gamme
SECAM L
PAL B/G
Fréquence
Canaux
Fréquence
Canaux
VHF
49 MHz ­ 65 MHz 2 ­ 4
47 MHz ­ 89 MHz
E2 ­ E4
(LOW)
X, Y, Z
E5 ­ E12
VHF
104 MHz
5 ­ 10
104 MHz
S1 ­ S20
(HIGH)
­ 300 MHz
CATV
­ 300 MHz
M1 ­ M10
U1 ­ U10
Hyper
300 MHz ­ 470 MHz CATV
302 MHz ­ 470 MHz S21 ­ S41
UHF
470 MHz ­ 862 MHz 21 ­ 69 470 MHz ­ 862 MHz E21 ­ E69


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3.1.3 Color (colour) bar signal,Color (colour) bar pattern ......... 3-1
3.1.4 Switch settings and standard precautions ....................... 3-1
3.1.5 EVR Adjustment .............................................................. 3-1
3.2 Servo circuit .......................................................................... 3-2
3.2.1 Switching point ................................................................ 3-2
3.2.2 Slow tracking preset ........................................................ 3-2
3.3 Video circuit .......................................................................... 3-2
3.3.1 D/A level .......................................................................... 3-2
3.3.2 EE Y/PB Y (S-VHS/VHS) level ......................................... 3-2
3.3.3 REC color (colour) level ................................................... 3-3
3.3.4 Video EQ (Frequency response) ..................................... 3-3
3.3.5 Auto picture initial setting ................................................. 3-4
3.4 Audio circuit .......................................................................... 3-4
3.4.1 Audio REC FM ................................................................. 3-4
3.5 Syscon circuit ....................................................................... 3-4
3.5.1 Timer clock ...................................................................... 3-4
3.6 PAL/SECAM Converter circuit .............................................. 3-5
3.6.1 Colour difference level ..................................................... 3-5
3.6.2 SECAM burst position ..................................................... 3-5
4. CHARTS AND DIAGRAMS
NOTES OF SCHEMATIC DIAGRAM .......................................... 4-1
CIRCUIT BOARD NOTES ........................................................... 4-2
4.1 BOARD INTERCONNECTIONS .......................................... 4-3
4.2 MAIN (VIDEO/AUDIO) SCHEMATIC DIAGRAM .................. 4-5
4.3 MAIN (ON SCREEN) SCHEMATIC DIAGRAM .................... 4-7
4.4 MAIN (SECAM) SCHEMATIC DIAGRAM ............................. 4-9
4.5 MAIN (SYSCON) SCHEMATIC DIAGRAM ........................ 4-11
4.6 MAIN (SW.REG) SCHEMATIC DIAGRAM ......................... 4-13
4.7 MAIN (TUNER) SCHEMATIC DIAGRAM ........................... 4-15
4.8 MAIN (SW/DISPLAY), MINI FRONT, S-JACK AND ADV. JOG
SCHEMATIC DIAGRAMS ..................................................... 4-17
4.9 MAIN (MAIN TERMINAL) SCHEMATIC DIAGRAM ............ 4-19
4.10 2D DIGITAL SCHEMATIC DIAGRAM
[HR-S6850MS/S7850MS/S7851MS] ............................... 4-21
4.11 3D/TBC(2M) SCHEMATIC DIAGRAM [HR-S8850MS] .... 4-23
4.12 TERMINAL (S-SUB) SCHEMATIC DIAGRAM ................. 4-25
4.13 TERMINAL (I/O) SCHEMATIC DIAGRAM ....................... 4-27
4.14 DEMODULATOR SCHEMATIC DIAGRAM ...................... 4-29
4.15 S-P CONVERTER SCHEMATIC DIAGRAM .................... 4-31
4.16 MAIN CIRCUIT BOARD ................................................... 4-33
4.17 2D DIGITAL AND 3D DIGITAL/2M CIRCUIT BOARDS ... 4-36
4.18 TERMINAL CIRCUIT BOARD ......................................... 4-37
4.19 S-P CONVERTER AND DEMODULATOR CIRCUIT BOARDS 4-38
4.20 FDP GRID ASSIGNMENT AND ANODE CONNECTION 4-39
4.21 REMOTE CONTROLLER SCHEMATIC DIAGRAMS ...... 4-40
4.22 WAVEFORMS .................................................................. 4-41
4.23 VOLTAGE CHARTS ......................................................... 4-43
4.24 CPU PIN FUNCTION ....................................................... 4-45
4.25 SYSTEM CONTROL BLOCK DIAGRAM ......................... 4-47
4.26 VIDEO BLOCK DIAGRAM ............................................... 4-49
4.27 AUDIO BLOCK DIAGRAM ............................................... 4-53
5. PARTS LIST
5.1 PACKING AND ACCESSORY ASSEMBLY <M1> ............... 5-1
5.2 FINAL ASSEMBLY <M2> .................................................... 5-2
5.3 MECHANISM ASSEMBLY <M4> ........................................ 5-4
5.4 ELECTRICAL PARTS LIST .................................................. 5-6
MAIN BOARD ASSEMBLY <03> ............................................... 5-6
2D DIGITAL BOARD ASSEMBLY <05>(MODEL:A,B,C) ......... 5-14
3D DIGITAL/2M BOARD ASSEMBLY <05>(MODEL:D) .......... 5-15
TERMINAL BOARD ASSEMBLY <06> ................................... 5-16
A/C HEAD BOARD ASSEMBLY <12> ..................................... 5-18
DEMOD BOARD ASSEMBLY <14> ........................................ 5-18
MINI FRONT BOARD ASSEMBLY(MODEL:B,C,D)<28> ........ 5-19
S JACK BOARD ASSEMBLY <36> ......................................... 5-19
ADV.JOG BOARD ASSEMBLY <38> ....................................... 5-19
LOADING MOTOR BOARD ASSEMBLY <55> ....................... 5-19
S/P CONVERTER BOARD ASSEMBLY <87> ........................ 5-19
Important Safety Precautions
INSTRUCTIONS
1. DISASSEMBLY
1.1 Disassembly flow chart ......................................................... 1-1
1.2 How to read the disassembly and assembly ........................ 1-1
1.3 Disassembly/assembly method ............................................ 1-1
1.4 Service position .................................................................... 1-4
1.4.1 How to set the "Service position" ..................................... 1-4
1.5 Mechanism service mode ..................................................... 1-4
1.5.1 How to set the "Mechanism service mode" ..................... 1-4
1.6 Jig RCU mode ...................................................................... 1-4
1.6.1 Setting the Jig RCU mode ............................................... 1-4
1.6.2 Setting the User RCU mode ............................................ 1-4
1.7 Servicing items related to video navigation .......................... 1-4
1.8 Emergency display function .................................................. 1-5
1.8.1 Displaying the EMG information ...................................... 1-5
1.8.2 Clearing the EMG history ................................................ 1-5
1.8.3 EMG content description ................................................. 1-6
1.8.4 EMG detail information <1> ............................................. 1-7
1.8.5 EMG detail information <2> ............................................. 1-8
2. MECHANISM ADJUSTMENT
2.1 Before starting repair and adjustment ................................... 2-1
2.1.1 Precautions ..................................................................... 2-1
2.1.2 Checking for proper mechanical operations .................... 2-1
2.1.3 Manually removing the cassette tape .............................. 2-1
2.1.4 Jigs and tools required for adjustment ............................. 2-2
2.1.5 Maintenance and inspection ............................................ 2-3
2.2 Replacement of major parts ................................................. 2-6
2.2.1 Before starting disassembling (Phase matching between
mechanical parts) ............................................................ 2-6
2.2.2 How to set the "Mechanism assembling mode" ............... 2-6
2.2.3 Cassette holder assembly ............................................... 2-6
2.2.4 Pinch roller arm assembly ............................................... 2-8
2.2.5 Guide arm assembly and press lever assembly .............. 2-8
2.2.6 A/C head ......................................................................... 2-8
2.2.7 Loading motor ................................................................. 2-8
2.2.8 Capstan motor ................................................................. 2-9
2.2.9 Pole base assembly (supply or take-up side) .................. 2-9
2.2.10 Rotary encoder ........................................................... 2-10
2.2.11 Clutch unit ................................................................... 2-10
2.2.12 Change lever assembly, direct gear, clutch gear and coupling gear 2-10
2.2.13 Link lever ..................................................................... 2-11
2.2.14 Cassette gear, control cam and worm gear ................ 2-11
2.2.15 Control plate ............................................................... 2-11
2.2.16 Loading arm gear (supply or take-up side) and
loading arm gear shaft .................................................. 2-12
2.2.17 Take-up lever, take-up head and control plate guide .. 2-13
2.2.18 Capstan brake assembly ............................................ 2-13
2.2.19 Sub brake assembly (take-up side) ............................ 2-13
2.2.20 Main brake assembly (take-up side), reel disk (take-up side)
and main brake assembly (supply side) ............................... 2-13
2.2.21 Tension brake assembly, reel disk (supply side) and
tension arm assembly ................................................. 2-14
2.2.22 Idler lever, idler arm assembly .................................... 2-14
2.2.23 Stator assembly .......................................................... 2-14
2.2.24 Rotor assembly ........................................................... 2-14
2.2.25 Upper drum assembly ................................................. 2-15
2.3 Compatibility adjustment .................................................... 2-16
2.3.1 FM waveform linearity ................................................... 2-16
2.3.2 Height and tilt of the A/C head ...................................... 2-17
2.3.3 A/C head phase (X-value) ............................................. 2-17
2.3.4 Standard tracking preset ............................................... 2-18
2.3.5 Tension pole position ..................................................... 2-18
3. ELECTRICAL ADJUSTMENT
3.1 Precaution ............................................................................ 3-1
3.1.1 Required test equipments ............................................... 3-1
3.1.2 Required adjustment tools ............................................... 3-1
TABLE OF CONTENTS
Section
Title
Page
Section
Title
Page
HR-S6850MS
HR-S7850MS
HR-S7851MS
HR-S8850MS
FLYING ERASE HEAD
NOT USED
USED
USED
USED
DIGITAL 3R/TBC/FRAME MEMORY
NOT USED
NOT USED
NOT USED
USED
YNR/CNR/S.COLOR
NOT USED / 2D/NOT USED NOT USED / 2D / NOT USED
NOT USED / 2D / NOT USED USED (3D) / 3D / USED (3D)
RE-TAKE/ASSEMBLE EDIT
NOT USED / A.F.E.
USED / Z.F.E.
USED / Z.F.E.
USED / Z.F.E.
INSERT/OPERATION,
NOT USED
USED/BUTTON
USED/BUTTON
USED/BUTTON
AUDIO DUBBING / OPERATION
HiFi LEVEL METER
NOT USED
USED
USED
USED
R.PAUSE TERMINAL
NOT USED
USED
USED
USED
REAR OUT
AUDIO L/R
AUDIO L/R & S-OUT
AUDIO L/R & S-OUT
AUDIO L/R & S-OUT
CABLE BOX OR DBS. BOX OR SAT CTL
OPTION
OPTION
OPTION
USED
CABLE MOUSE
OPTION
OPTION
OPTION
PROVIDED
RCU
V13 SMALL 10KEY
V13 SMALL 10KEY
V13 SMALL 10KEY
V13 LCD
RCU TYPE / COLOR
V14#E11-S / SILVER
V14#E11-S / SILVER
V14#E11-S / SILVER
V14#E5 / LIGHT BEIGE
RCU MBR /IR CODE
NOT USED / A
NOT USED / A
NOT USED / A
USED (TV, SAT/CABLE) / A, B
F-AV CAP
NOT USED
USED
USED
USED
WINDOW COLOR
SMOKE LIGHT GRAY
SMOKE LIGHT GRAY
GREEN
SMOKE LIGHT GRAY
The following table lists the differing points between Models ( HR-S6850MS, HR-S7850MS, HR-S7851MS and HR-S8850MS) in this series.


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Important Safety Precautions
Prior to shipment from the factory, JVC products are strictly inspected to conform with the recognized product safety and electrical codes of the
countries in which they are to be sold. However, in order to maintain such compliance, it is equally important to implement the following precautions
when a set is being serviced.
Fig.1
1. Locations requiring special caution are denoted by labels and in-
scriptions on the cabinet, chassis and certain parts of the product.
When performing service, be sure to read and comply with these
and other cautionary notices appearing in the operation and serv-
ice manuals.
2. Parts identified by the
! symbol and shaded (
) parts are
critical for safety.
Replace only with specified part numbers.
Note: Parts in this category also include those specified to com-
ply with X-ray emission standards for products using
cathode ray tubes and those specified for compliance
with various regulations regarding spurious radiation
emission.
3. Fuse replacement caution notice.
Caution for continued protection against fire hazard.
Replace only with same type and rated fuse(s) as specified.
4. Use specified internal wiring. Note especially:
1) Wires covered with PVC tubing
2) Double insulated wires
3) High voltage leads
5. Use specified insulating materials for hazardous live parts. Note
especially:
1) Insulation Tape
3) Spacers
5) Barrier
2) PVC tubing
4) Insulation sheets for transistors
6. When replacing AC primary side components (transformers, power
cords, noise blocking capacitors, etc.) wrap ends of wires securely
about the terminals before soldering.
Power cord
Fig.2
10. Also check areas surrounding repaired locations.
11. Products using cathode ray tubes (CRTs)
In regard to such products, the cathode ray tubes themselves, the
high voltage circuits, and related circuits are specified for compli-
ance with recognized codes pertaining to X-ray emission.
Consequently, when servicing these products, replace the cath-
ode ray tubes and other parts with only the specified parts. Under
no circumstances attempt to modify these circuits.
Unauthorized modification can increase the high voltage value and
cause X-ray emission from the cathode ray tube.
12. Crimp type wire connector
In such cases as when replacing the power transformer in sets
where the connections between the power cord and power trans-
former primary lead wires are performed using crimp type connec-
tors, if replacing the connectors is unavoidable, in order to prevent
safety hazards, perform carefully and precisely according to the
following steps.
1) Connector part number : E03830-001
2) Required tool : Connector crimping tool of the proper type which
will not damage insulated parts.
3) Replacement procedure
(1) Remove the old connector by cutting the wires at a point
close to the connector.
Important : Do not reuse a connector (discard it).
Fig.7
cut close to connector
Fig.3
(2) Strip about 15 mm of the insulation from the ends of the
wires. If the wires are stranded, twist the strands to avoid
frayed conductors.
15 mm
Fig.4
(3) Align the lengths of the wires to be connected. Insert the
wires fully into the connector.
Connector
Metal sleeve
Fig.5
(4) As shown in Fig.6, use the crimping tool to crimp the metal
sleeve at the center position. Be sure to crimp fully to the
complete closure of the tool.
I
·Precautions during Servicing
7. Observe that wires do not contact heat producing parts (heatsinks,
oxide metal film resistors, fusible resistors, etc.)
8. Check that replaced wires do not contact sharp edged or pointed
parts.
9. When a power cord has been replaced, check that 10-15 kg of
force in any direction will not loosen it.
1.2
5
2.0
5.5
Crimping tool
Fig.6
(5) Check the four points noted in Fig.7.
Not easily pulled free
Crimped at approx. center
of metal sleeve
Conductors extended
Wire insulation recessed
more than 4 mm
S40888-01


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·Safety Check after Servicing
Examine the area surrounding the repaired location for damage or deterioration. Observe that screws, parts and wires have been returned
to original positions, Afterwards, perform the following tests and confirm the specified values in order to verify compliance with safety
standards.
1. Insulation resistance test
Confirm the specified insulation resistance or greater between power cord plug prongs and exter-
nally exposed parts of the set (RF terminals, antenna terminals, video and audio input and output
terminals, microphone jacks, earphone jacks, etc.). See table 1 below.
2. Dielectric strength test
Confirm specified dielectric strength or greater between power cord plug prongs and exposed acces-
sible parts of the set (RF terminals, antenna terminals, video and audio input and output terminals,
microphone jacks, earphone jacks, etc.). See table 1 below.
3. Clearance distance
When replacing primary circuit components, confirm specified clearance distance (d), (d') be-
tween soldered terminals, and between terminals and surrounding metallic parts. See table 1
below.
4. Leakage current test
Confirm specified or lower leakage current between earth ground/power cord plug prongs and
externally exposed accessible parts (RF terminals, antenna terminals, video and audio input and
output terminals, microphone jacks, earphone jacks, etc.).
Measuring Method : (Power ON)
Insert load Z between earth ground/power cord plug prongs and externally exposed accessible
parts. Use an AC voltmeter to measure across both terminals of load Z. See figure 9 and following
table 2.
5. Grounding (Class 1 model only)
Confirm specified or lower grounding impedance between earth pin in AC inlet and externally exposed accessible parts (Video in, Video out,
Audio in, Audio out or Fixing screw etc.).
Measuring Method:
Connect milli ohm meter between earth pin in AC inlet and exposed accessible parts. See figure 10 and grounding specifications.
Fig. 10
Fig. 9
Fig. 8
Table 1 Specifications for each region
Table 2 Leakage current specifications for each region
Note: These tables are unofficial and for reference only. Be sure to confirm the precise values for your particular country and locality.
II
S40888-01
ab
c
V
A
Externally
exposed
accessible part
Z


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1-1
-----------------
-----------------
-----------------
-----------------
[1]
Top cover,
D1 4(S1a), (S1b)
Bracket
2(S1c)
[2]
Front panel assembly
D2 CN7001(WR2a),
<Note 2a>
CN916(WR2b),
<Note 2b>
4(L2a), 3(L2b)
<Note 2c>
ADV. Jog board assembly
2(S2a)
S Jack board assembly
2(S2b)
[3]
Drum assembly
D3 CON1(WR3a),
<Note 2c>
CN1(WR3b),
(S3a), (S3b), (S3c)
(Inertia plate)
4(L3a)
(Roller arm assy)
(P3), (L3b)
[4]
Mechanism assembly D4 CN2001(WR4a),
<Note 2c>
(S4a),(S4b),
<Note 4a>
(S4c), (S4d), 2(L4)
[5]
S/P Converter board
D5 CN601(WR5a),
<Note 2c>
assembly
2(S5c)
Main board assembly
(S5a),3(S5b),7(L5a)
[6]
Bottom cover
D6 2(L6a), 9(L6b)
<Note 6a>
SECTION 1
DISASSEMBLY
1.3 Disassembly/assembly method
1.1 Disassembly flow chart
This flowchart lists the disassembling steps for the cabinet
parts and P.C. boards in order to gain access to item(s) to
be serviced. When reassembling, perform the step(s) in re-
verse order. Bend, route and dress the flat cables as they
were originally laid.
1.2 How to read the disassembly and assembly
Note:
·
The bracketed ( ) WR of the connector symbol are as-
signed nos. in priority order and do not correspond to
those on the spare parts list.
(5) Adjustment information for installation
Top cover, Bracket
Front panel assembly,
ADV. Jog board assembly,
S Jack board assembly
Drum assembly
Mechanism assembly
S/P Converter board assembly,
Main board assembly
Bottom cover
[1]
[2]
[3]
[4]
[5]
[6]
Step/
LocNo.
Part Name
Fig.
No.
Point
Note
-----------------
(1)
(2)
(3)
(4)
(5)
Step/
LocNo.
Part Name
Fig.
No.
Point
Note
[1]
Top cover,
D1 4(S1a),(S1b),3(L1a),
<Note 1a>
2(SD1a),(P1a),(W1a),
CN1(WR1a),
Bracket
2(S1c)
<Example>
(1) Order of steps in Procedure
When reassembling, perform the step(s) in the reverse order.
These numbers are also used as the identification (location) No.
of parts Figures.
(2) Part name to be removed or installed.
(3) Fig. No. showing procedure or part location.
(4) Identification of part to be removed, unhooked, unlocked,
released, unplugged, unclamped or unsoldered.
P= Spring, W= Washer, S= Screw, L= Locking tab, SD= Solder,
CN**(WR**)= Remove the wire (WR**) from the connector
(CN**).
<Note 2a>
· When reattaching the Front panel assembly, make sure that
the door opener "a" of the Cassette holder assembly is low-
ered in position prior to the reinstallation.
<Note 2b>
· When reattaching the Front panel assembly, pay careful at-
tention to the switch lever not to make it touch the switch
knob "b" of the Main board assembly from the side.
<Note 2c>
· Be careful not to damage the connector and wire etc. during
connection and disconnection.
When connecting the wire to the connector, be careful with
the wire direction.
<Note 4a>
· When it is required to remove the screws (S4a to S4b) re-
taining the Mechanism assembly, please refer to the "Pro-
cedures for Lowering the Cassette holder assembly"(See
on page 1-2).
· When reattaching the Mechanism assembly to the Main
board assembly, take care not to damage the sensors and
switch on the Main board assembly.
· When removing the Mechanism assembly only, unhook the
two spacers connecting it with the Main board assembly
with pliers from the back side of the Main board assembly
first, and then remove the Mechanism assembly.
· The wire (WR4a) has excess length that may be loose, as it
is quite long. After inserting the wire and connectors, the
loose portion of the wire should be taken up and accommo-
dated between the A/C head base and the main deck.
<Note 6a>
When removing the bottom cover, push down the two tabs
(L6a) to slide the bottom cover.
-----------------