Casio QV-5500SX Troubleshooting guide

Ver.1 Dec / 1999
R
QV-5500SX
MAR. 1999
(without price)
(KX-712)
INDEX

CONTENTS
SPECIFICATIONS ....................................................................................................................................... 1
BLOCK DIAGRAM ...................................................................................................................................... 3
ADJUSTMENT ............................................................................................................................................ 4
1. Whole unit .......................................................................................................................................... 5
1-1. Loading ADJ program ................................................................................................................. 5
1-2. White balance and Sensitivity adjustment ................................................................................ 7
1-3. White scratch correction............................................................................................................. 8
1-4. Flash operation and charge current check ............................................................................... 9
1-5. VCOM DC adjustment................................................................................................................ 11
1-6. Current consumption check ..................................................................................................... 11
2. D-PCB Assy ...................................................................................................................................... 12
2-1. Operation check......................................................................................................................... 12
3. L,BL PCBs Assy............................................................................................................................... 13
3-1. VCC2 adjustment and VCC13, VCC7, VEE2 checks ............................................................... 13
3-2. VCC free run frequency adjustment ........................................................................................ 13
3-3. BL drive voltage adjustment..................................................................................................... 14
3-4. VCOM AC and VCOM DC coarse adjustment.......................................................................... 14
3-5. Brightness voltage setting and contrast adjustment............................................................. 15
4. L,BL PCBs Assy............................................................................................................................... 16
4-1. VCC18, VCC15, VEE7 adjustments ........................................................................................... 16
DISASSEMBLY ......................................................................................................................................... 17
EXPLODED VIEW ..................................................................................................................................... 25
PARTS LIST .............................................................................................................................................. 26
PRINTED CIRCUIT BOARDS ................................................................................................................... 32
SCHEMATIC DIAGRAMS ......................................................................................................................... 37
TROUBLESHOOTING .............................................................................................................................. 44
APPENDIX................................................................................................................................................. 45
1. The distinction method of a model ................................................................................................. 45

— 1 —
SPECIFICATIONS
File Format Static, Panorama: JPEG standard; Movie: AVI/JPEG (for recording to CompactFlash card)
Recording Medium CompactFlash card
Standard Memory Capacity/ Static S (1280 x 960) / 14 (500KB/image)
Number of Image Files/ F (1280 x 960) / 19 (352KB/image)
Computer Output Image Size N (1280 x 960) / 33 (200KB/image)
E (640 x 480) / 55 (112KB/image)
Movie: File Format AVI
3.2seconds (320x240) / 8sets (896KB / image)
6.4seconds (320x240) / 4sets (1792KB / image)
9.6seconds (320x240) / 3sets (2100KB / image)
3.2seconds (160x120) / 30sets (224KB / image)
6.4seconds (160x120) / 16sets (448KB / image)
9.6seconds (160x120) / 10sets (672KB / image)
Movie: File Format JPEG
3.2seconds (320x240) / 6sets
6.4seconds (320x240) / 3sets
9.6seconds (320x240) / 2sets
3.2seconds (160x120) / 27sets
6.4seconds (160x120) / 13sets
9.6seconds (160x120) / 9sets
*When using 8MB CF card.
Image Deletion Single image; all images in a folder; all images in memory (with image protection)
Imaging Element 1/3-inch CCD (Total Pixels: 1.31 million, Effective Pixels; 1.25 million)
Lens f/2.8; f = 5.47mm (equivalent to 36mm lens for 35mm film)
Zoom Digital 2x, 4x
Focusing External Phase Difference Auto Focus; manual focus with macro mode and focus lock
Focus Range 0.3m to ∞for Normal focus; 10cm for macro (approximately 10cm to ∞with manual focus),
from surface of protective lens filter
Exposure Control Light Metering: Multi-pattern, center point, spot by CCD
Exposure: Program AE
Exposure Compensation: –2EV to +2EV (1/2EV units)
Shutter CCD electronic shutter; mechanical shutter, 1/8 to 1/500 second (1 second in Night Scene Mode)
Aperture f/2.8, 4, 5.6, 8, 11, 16 auto
White Balance Automatic, fixed (4 modes), manual switching
Self-timer 10 seconds, 2 seconds
Built-in Flash Flash Modes: AUTO, ON, OFF, Red eye reduction
Flash Range: Approximately 0.7 to 2 meters
Recording Functions Continuous, quick shutter, AEB, multiple exposure, night scene, single-image, self-timer, movie,
panorama, macro
Monitor 1.8" TFT, low-glare color HAST LCD (122,100 pixels, 555 x 220)
Viewfinder Monitor or optical viewfinder
Clock Built-in quartz digital timepiece for time and date recording and storage with image data; auto
calendar up to 2049
Input/Output Terminals DIGITAL IN/OUT, AC adaptor connector, VIDEO OUT (NTSC, PAL)

— 2 —
Power Supply Four AA-size alkaline or lithium batteries
Four AA-size nickel-hydrogen rechargeable batteries (NP-H3)
AC adaptor (AD-C620)
Battery Life The values noted below indicate the number of hours before battery failure under normal
operating temperature (25°C). These values are for reference only, and do not guarantee that
any particular set of batteries actually will provide the service life indicated. Low temperatures
shorten battery life.
•The above guidelines are based on the following battery types:
Alkaline: MX1500 (AA) DURACELL ULTRA
Lithium: Energizer
•Battery life varies with brand
Continuous recording values show the number of shots without using the flash. The number of
shots depends on use of the flash and whether flash is turned on or off.
Power Consumption Approximately 7.3W
Dimensions 131(W) x 69(H) x 43(D) mm
Weight Approximately 250g (excluding batteries)
Standard Accessories 8MB COMPACTFLASH memory card; strap; soft case; lens cap; video cable; data transfer
cable; PC Link CD-ROM; four LR6 alkaline batteries; Owner’s manual
AA-size Alkaline
Batteries LR6
Approximately 110
minutes
Approximately 300
shots
AA-size Lithium
Batteries FR6
Approximately 210
minutes
Approximately 840
shots
Type of
Operation
Continuous
Playback
Continuous
Recording
*The camera also has a lithium battery that powers its built-in clock. When the power of this battery becomes weak, take the
camera to your CASIO Service Provider to have it replaced.
*The liquid crystal panel built into this camera is the product of precision engineering, with an effective pixel rate of 99.99%. This
also means, however that 0.01% of the pixels can be expected to fail to light or to remain lit at all times.
*U.S.A model can see a VIDEO OUT picture at the time of REC MODE.
( Other models cannot be carried out.)

— 3 —
BLOCK DIAGRAM
1.8"TFT
C0D18T1022
LZ23J3V
CCD
V-Dr
LR36685
H-BAFFER
TK16140
C-PCB
HD49323AF
CDS/AGC/ADC
V3
V1
CH3A
CH1A
V4
V2
CH3B
SUB
CH1B
OFDC
RESET
ADCK
DB0
DB9
RSTCCD
SHP
SHD
CLAMP
SDI
SCK
LOAD
H1
H2
RLED
GLED
COMMAND
STATUS
/SCK
/FLB
/SHATTER
/FLB
/LSRT
AF-PCB
ST-UNIT
Xe
LAMP
DRIVER
DRIVER
SUB
CPU
EEPROM
PW-PCB
D-PCB
L-PCB
DCAM-101F
CF
16Mbit
DRAM X2
128Mbit(50ns)
MSM82C55A
IR3Y26A1
VIDEO/RGB
SW
VIDEO75Ω
CM7018
VIDEO
JACK
DC
JACK
LCD
ON/OF
F
K-PCB
KEY
MODE
DISP
MENU
S/N/F/E
S-TIMER
FLASH
KEY
SHUTTER
(+)
(-)
JK-PCB
BL-PCB
CL-UNIT
VCC1-ST
VCC5-1
GND
VCC1-ST
VCC5-1
GND
JK-IN
GND
PW0~3
ADPTN
GND5
VCC5-1
SLED
DGND3
VCC3-1
EVCC3
AGND3
VCC3-2
GND
VCC1-3
VCC1-L
RTCBAT
PLED
DGND3
PACT
KOUT0
KOUT1
VCC3-1
KIN0
KIN1
KIN2
KIN3
SOP
SIP
DGND5
LGND
VIDEO
VGND
VSW
BLCNT
BL-VCC BLGND BLACTB
VGH
VREFH
VGL
VREFL
GRES
GPCK
GSRT
RESET
MODE2
CS
VCOM
VBC
SRTR
SRTL
OE
CLR
HCNT
MCLK
MODE1
VSS
GOUT
BOUT
VDD
VSH
B,G
R/VIDEO
CFCOVER
VCC5-1
CSYNC
RIGHT
VCC1-L
LGND
BLCONT
PWCONT
DGND3
JKSW
PLAY/REC
BLACTB
VCC3-1
SDIPO
SDOPO
VCC18
VCC5-4
VCC15
GND4
VCC3-3
GND3
DGND
VCC
AGND
5V
PGND
V.PM
12.75V
7.5V
5.0V
-14.5V
3.0V
6.0V
VCC13
VCC7
VCC2
VEE2
BL-VCC
VDD
20pin
20pin
26pin (C to F)
10pin (B to B)
(B to B)
10pin (B to B)
14pin
(C to FPC)
20pin
20pin
(B to B)
(C FPC C)
16pin
60pin
(C FPC B)
51pin
15pin
10pin
SGND
VA
LTTRGN
FBN
PREN
/SHUTTER
10pin
3.3V 3.3V 22V 15V -8V 5.0V
VCC3-1
VCC3-2
VCC3-3
EVCC3 VCC18 VEE7 VCC5-1
VCC5-2
VCC5-3
VCC5-4
VCC15
POWER
LED
RTC
RS5C348
Photo
sensor
Comparator
Battery voltage
Booster
2-color LED
Lens
unit
Voltage regulator
RGB interface TFT controller
Driver
Serial
buffer
Flash/Mask memory
Voltage
detector
Extender I/O
Voltage regulator
Timer
LED
LCD module
Backlight
Controller
Back-up capacitor
Batteries Serial
port
Ajack
~

— 4 —
ADJUSTMENT
1. Adjustments to be done
(1) Whole unit
1. Loading ADJ program
2. White balance, Sensitivity
3. White scratch correction
4. Flash operation and charge current check
5. VCOM-DC adjustment
6. Current consumption
Note:
When the lens ass'y is replaced, adjustment should be done in order of above 1, 2, and 3.
(2) D-PCB
1. Function check
(3) L and BL PCBs
1. VCC2 adjustment and VCC13, VCC7, VEE2 voltage check
2. VCO free run frequency adjustment
3. Backlight drive voltage adjustment
4. VCOM AC adjustment and VCOM DC coarse adjustment
5. Brightness voltage setting and contrast adjustment
(4) PW-PCB
1. VCC18, VCC15, VEE7 voltage adjustment
2. Necessary equipment
1. PC (OS : Windows 95 or 98)
2. Link cable
3. Digital oscilloscope
4. Voltage regulator
5. Ammeter
6. AC adaptor
3. Caution
Use an AC adaptor for camera's power source unless otherwise specified.
Do not tell outsider about the camera's test program mode.
Do not execute other programs than specified in this manual.

— 5 —
1. Whole unit
1-1. Loading ADJ program
Camera mode: PLAY mode
Necessary program: adj712f.exe,712_0212.adj and adj712k.exe
Adjustments and Checks
(1) Insert CompactFlash card and turn the camera on for PLAY mode.
(2) Connect the camera‘s 3-pin jack and PC’s RS232C port with a link cable.
(3) Execute adj712f.exe on Windows 95 or 98. (Fig. 1)
(4) Open "712_0212.adj" file using File/Open command.
(5) Click [Trans] button.
● If the loading is done properly, screen indicates “send ok”. (Fig. 2)
●If the loading was erroneous, “11RcvERR00” will be shown on the screen. (Fig. 3)
PC
RS232C port
Link cable
QV-5500SX
(Fig. 1)
(Fig. 2) (Fig. 3)

— 6 —
(6) The firstADJ program has been done when “send ok” is displayed.
Close the program then execute “adj712k.exe”. (Fig. 4)
(7)Click [Rgain*=1.07, Bgain*=1.09] button.
● If the program has been completed correctly, screen shows “Replace complete”. (Fig. 5)
● If the program has been erroneously executed, “11RcvERR00” will be shown. (Fig. 6)
(8) The program ends.
(Fig. 4)
(Fig. 5) (Fig. 6)
TEST MODE
WHITE NOISE DATA NO
LOADER 10
ADj. 99000212
PROG 99.02.13.20.28
GMENU 99.02.05.14.47
NOTE:The left figure is for a reference. The actual screen may differ.
ADJ program version number check
Insert CompactFlash in the camera and turn the camera on while pressing down Flash and shutter
buttons.
Check for ADJ version(displayed as; ADJ 99000212) on the TEST MODE screen. (Fig. 7)
Turn the camera off then on again and make sure that the camera records and play backs pictures
normally.
(Fig. 7)

— 7 —
1-2. White balance and sensitivity adjustments
1. Necessary equipment
(1) Simplified viewer (e.g. Kenko Light Box handy5000) which is modified to be DC powered exter-
nally.
(2) Power source (Output voltage; 0 ~ 10V over, output current; 0 ~ 1A over)
(3) ND filter (ND20)
(4) Color temperature conversion filter (LA50)
*Though the above filters are provided from Casio as parts (refer to the parts list), they are also
available from camera shops.
2. Settings
(1) Apply 6V from the power source to the simplified viewer.
(2) Turn the viewer on and leave it for approximately 30 minutes to stabilize the intensity and the color
temperature.
3. Adjustment method
(1) Set the camera on Test Mode 2 menu by the following procedures.
• Turn the function switch on REC mode.
• Turn the power on while pressing down Flash and shutter buttons (Test Mode display is shown on
the screen.)
• Press Macro button twice then push MENU button (MENU 2 screen will be displayed.)
• Select 1. CCD ADJUST and press shutter button (SHUT TO START will be shown.)
(2) Place color temperature conversion filter (LA50) on the center of the viewer’s illumination surface.
(3) Stick the camera to color conversion filter so that camera lens is on the center of the filter.
(4) Push the shutter button.
(5) White balance initial value is loaded when “RGB ADJUST COMPLETE” is displayed.
(6) Remove color conversion filter from the viewer.
(7) Place ND filter on the center of the viewer’s illumination surface.
(8) Stick the camera to the ND filter so that camera lens is on the center of the filter.
(9) Push the shutter button.
(10) Sensitivity adjustment is completed when “SENS ADJ COMPLETE” is displayed.
(11) Turn the camera power off.
Equipment needed to execute white balance and sensitivity adjustment
No. 1
No. 2
ADJ SOFT
CCD ADJUST
CCD SENS ADJUST
Color temperature
(K) light source 1
4400 ±200
Light intensisty
(cd/m2) light source 2
500 ±80
Note
No specified figure for
light intensity
No specified figure for
color temperature
Light source (viewer)

— 8 —
1-3. White scratch correction
1. Necessary equipment
(1) Simplified viewer (e.g. Kenko Light Box handy5000) which is modified to be DC powered exter-
nally.
(2) Power source (Output voltage; 0 ~ 10V over, output current; 0 ~ 1A over)
(3) Use two ND filter together, one ND10 and one ND20, placing one on the top of the other.
*Though the ND filter is provided from Casio as parts (refer to the parts list), it is also available from
camera shops.
2. Settings
(1) Apply 6V from the power source to the simplified viewer.
(2) Turn the viewer on and leave it for approximately 30 minutes to stabilize the intensity and the color
temperature.
3.Adjustment method
(1) Set the camera on Test Mode 2 menu by the following procedures.
• Turn the function switch on REC mode.
• Turn the power on while pressing down Flash and shutter buttons (Test Mode display is shown on
the screen.)
• Press Macro button twice then push MENU button (MENU 2 screen will be displayed.)
• Select 10. WHITE NOISE DETECT. (do not push the shutter button.)
(2) Place ND filter on the center of the viewer’s illumination surface.
(3) Stick the camera to the ND filter so that camera lens is on the center of the filter.
(4) Push the shutter button and wait for a moment.
(5) Sensitivity adjustment is completed when “SENS ADJ COMPLETE” is displayed.
(6) Turn the camera power off.
Equipment needed to execute white balance and sensitivity adjustment
No. 3
ADJ SOFT
WHITE NOISE ADJUST
Light intensisty
(cd/m2) light source 2
50 ±5
Note
No specified figure for
color temperature
Light source (viewer)

— 9 —
1-4. Flash operation and charge current check
Conditions
• Perform the checking after flash adjustment.
• Provide 6.0 ±0.1V from DC in jack.
• Turn the camera on REC mode.
Adjustment and checking
(1) Shoot a picture with flash on mode.
(2) Shoot a picture with red-eye reduction mode.
(3) Shoot a picture with macro mode.
(4) Set the camera on play mode and check the pictures on the monitor screen.
(5) Record trigger pulses of the above (1), (2), and (3) pictures on a digital oscilloscope.
(6) Shoot a picture with flash off mode and make sure that the flash does not light.
Make sure that the DC in 6Vcurrent is less than 1.3A.
Note:
Pictures (1) and (2) should not be whitish, darkish, or abnormally colored.
Flash lens face
Monitor
Digital oscilloscope Probe close to
flash lens face
QV-5500SX
Earth of hte probe
Should be hooked as shown above.
TIME : 1.0 sec/DIV
VOLTS: 1 V/DIV (AC mode)

— 10 —
Flash trigger waveform
1. Normal waveform TIME : 1 µsec/DIV
VOLTS : 1 V/DIV
(2) When trigger skipping occurs on the first
negative pulse.
ACQUIRE
NORMAL 1 ENVELOPE 2
AVS REPET ON | OFF SAVE ON ON | OFF
CH1 1V 757µVUERT1µV
First positive
pulse.
First negative
pulse.
OK if second positive pulse is shown.
2. NG waveforms when trigger skipping occurs.
(1) When trigger skipping occurs on the first
positive pulse.

— 11 —
1-5. VCOM DC adjustment
Conditions
1. Test mode 50 % raster image
2. Provide 6.0 ±0.05V voltage from DC in jack.
Adjustment and checking
(1) Execute 50 PERCENT GRAY on the test mode.
• While pushing down Flash and shutter button, turn the camera on.
• Push the Flash button twice then press MENU button (MENU 1 display will be shown.)
• Select 50 PERCENT GRAY then press the shutter button.
(2) Monitor the photo sensor amplifier output via a low-pass filter of cutoff frequency 60Hz.
Monitoring the oscilloscope screen, adjust VR320 to minimize 60Hz ripple waveform.
Notes:
Perform the adjustment after you replaced the display module.
Use only specified jig for replacing the flash lamp.
1-6. Current consumption check
Condition
Set the camera on play mode.
Adjustment and checking
(1) Current consumption (DC in = 6.0 ±0.1V)
(2) Reducing the voltage from 6V, make sure that the battery capacity indicator is changed.
DC in = 4.65 ±0.05V (Play mode)
Notes:
Maximum current in play mode; 500mA
Reference: maximum current in rec mode; 800mA (flash is not charging)
Photo diode
S1153 L.P.F
C2719
LCD QV-5500SX
Oscilloscope
Photo sensor Amp
Minimize the
ripple components

— 12 —
2. D-PCBAssy
2-1. Operation check
Condition
Set the camera on play mode.
Adjustment and checking
1. Clock pulse frequency
Check if CP400 is 32.768 ±0.002kHz
2. Procedures
(1) Connect a PC and the camera with a link cable.
(PC; COM port, Camera; 3-pin jack)
(2) Store GP2JPEG test file (8 files) in a CompactFlash card.
Ref.bay / Ref.cb / Ref.cr / Ref.jpg / Ref.y / Refdec.cb / Refdec.cr / Refdec.y
(3) Insert the Compact flash in the camera.
(4) Turn the camera on ( in Play mode).
(5) Double click Dt712.exe.
(6) DOS prompt opens and checking starts automatically.
(7) In the key check mode, push all the keys.
(8) Press space bar of the PC for LED and LCD control check.
(9) When the camera functions correctly, the camera turns itself off then on again after 5 seconds.
NOTE : If you wish to escape D PCB test, press PC's ESC button.
3. DT program
Program to be used; dt712
Check the followings;
(1) Serial data communication
(2) ROM version number
(3) Graphic menu version number
(4) DRAM
(5) CompactFlash memory
(6) Voltage detection (displayed as HIGH)
(vcc1-3 voltage… high; 6.0 ±0.1V, middle; 4.35 ±0.05V, low; 3.85 ±0.05V)
(7) Each operation mode
1) REC/PLAY modes
2) VIDEO jack
3) AC adaptor
(8) EEPROM test
(9) CP2 JPEG test
(10) Button operations
(11) LED1,2,3 on/off
(12) TFT-LCD on/off
(13) Time setting, time function
(14) Timer test
(15) Turn the camera off
4. Make sure that RGB and VIDEO signals are provided.
Check VIDEO output in NTSC and PAL systems.

— 13 —
3. L, BL PCBs Assy
3-1. VCC2 adjustment and VCC13, VCC7, VEE2 checks
Adjustment and checking
Adjust VR151 so that VCC2 (CP172) is 5.0 ±0.02V.
Turn the power off and make sure that all the voltages are 0V.
Notes :
<Voltages> VCC7 = 7.0 ~ 8.0V
VCC13 = 11.8 ~ 13.7V
VEE2 = -13.2 ~ -15.4V
3-2. VCC free run frequency adjustment
Condition
1. Connect CP763 (SYF) and CP700 (GND).
Adjustment
Monitoring CP734 (HDB) with frequency counter, adjust VR755 so that the frequency is 15.734 ±
0.1kHz.
Note :
Perform the adjustment in room temperature of 20 ±10˚C.
Power
Supply
L-PCB
SYF
(CP763)
AGND
(CP700)
HDB
(CP734)
Frequency
counter

— 14 —
3-3. BL drive voltage adjustment
Checking
Make sure that CP900 (BL-VCC) is 5.4 ±0.2V.
3-4. VCOM AC and VCOM DC coarse adjustment
Adjustment
(1) Check if VCOM output (CP716) amplitude is 6.6±0.3V.
(2) Adjust VR320 so that High level of VCOM output (CP716) becomes 4.8 ±0.2V.
Power
Supply
L-PCB
VCOM
(PC716) High level
amplitude
6.6 [V]
Oscilloscope
4.8 [V]
0 [V]
–1.8 [V]

— 15 —
L-PCB
R, G, B,
CSYNC signal
(1.0 Vp-p)
(CP301)
(CP302)
(CP303)
(CP309)
BOUT
terminal
(CP375)
Signal
generator
Power
Supply
Figure 3-1, 3-2
Digital oscilloscope
2.85V ±0.05V
(pedestal-10 step)
3.5 ±0.05V
(pedestal-pedestal)
3-1 3-2
3-5. Brightness voltage setting and contrast adjustment
Condition
Nature of signal : 10 step (NTSC)
Adjustment
(1) Execute GRAY SCALE (10STEP) on the test mode.
• While pushing down Flash and shutter button, turn the camera on.
• Push the Flash button twice then press MENU button (MENU 1 display will be shown.)
• Select GRAY SCALE (10STEP) then press the shutter button.
(2) Triggering with FRP (CP380) signal, adjust BOUT signal as described below.
(3) Adjust RGB-AMP (VR340) so that pedestal – pedestal voltage becomes 3.5 ±0.05V.
(4) Adjust contrast VR (VR344) so that contrast terminal (CP376) voltage is 3.0 ±0.05V temporarily.
(5) Adjust Bright VR (VR381) so that pedestal – 3rd step is 2.20 ±0.05V.
(6) Adjust Contrast VR (VR344) so that pedestal – 10th step is 2.85 ±0.05V.
Note :
Make sure that the waveform is not distorted.

— 16 —
4. PW PCB Assy
4-1. VCC18, VCC15, VEE7 adjustments
Adjustment
Apply 5.0 ±0.05V on VCC1-1 and adjust VR120 so that VCC18 (CP121) is 22.0 ±0.5V.
Adjust VR125 so that VCC15 (CP125) is 15.5 ±0.2V.
Adjust VR130 so that VEE7 (CP133) is –8.0 ±0.2V.
Note
Perform VCC15 adjustment after VCC18 adjustment is done.

— 17 —
DISASSEMBLY
1.Take CompactFlash card from the camera. 5.Open the battery cover and unhook the case.
Hook
2.Remove the batteries. 6.Unhook the case using a screw driver.
Hook
3.Remove 2 screws from side body of the camera. 7.Remove the upper case.
Screws 8.Remove the top case.4.Remove 1 screw from the bottom of the camera.
Screw

— 18 —
9. Open the battery cover and remove 1 screw. 13.Remove 3 screws on the key PCB.
Screw Screw
10.Unhook the battery holder. 14.Disconnect the flat cable and remove key PCB.
Hook Flat cable
11. Remove the frame block. 15.Peel off the insulation sheet from the bottom.
Insulation sheet
12.Peel off the insulation sheet on the key PCB. 16.Remove a screw with washer affixing PW PCB.
Insulation sheet Screw