Casio CTX870IN Service Manual
CT-X870IN / VER.2
DISASSEMBLY
1. Precautions
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About repair
• The fi gures in this chapter show a prototype, so the appearance of parts may slightly diff er from the
actual parts.
• To avoid damages to the instrument and fl oor, lay the instrument on a mattress or blanket before
starting disassembling.
• There are several kinds of screws. Be sure to use the correct type of screws when assembling.
It is advisable to sort the screws as shown below after removing them.
• If a screw cap is attached to the screw, remove it.
When assembling, reattach the screw cap.
• Check how cables are wired before removing cables.
When assembling, wire the cables in the same manner as they were before disassembly.
• If a cable is bound by cable tie, tape or similar item, remove it as necessary.
When assembling, bind the cable as it was before disassembly.
• The number of pins of ribbon cable is sometimes diff erent from the number of pads of PCB.
Solder the pin No. 1 (orange) of cable on the pad No. 1 of PCB.
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Before starting repair or servicing
• Remove the AC adaptor, AC cord or batteries.
• Remove accessories such as the music stand.
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2. Disassembly Procedure
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Flowchart
Assembled Product
A. Case
B. Main Panel
C. Side Panel
F. BENDER-UNIT
G. SPEAKER
CT-X870IN / VER.2
D. PCB UNIT/MAIN
E. BACK LIGHT UNIT Disassembly of the Backlight Block
H. KEY
I. PCB UNIT/KEYBOARD/KYA
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A. Removing the Case
A-1. Undo screws on the bottom surface.
• To remove the main panel, undo 7 screw A.
• To remove the left side panel, undo 7 screw A and 5 screw B.
• To remove the right side panel, undo 7 screw A and 5 screw C.
CT-X870IN / VER.2
Right side panelLeft side panel Main panel
Notes on Assembly
• Check that cables are not covering the screw hole before tightening a screw.
: Screw C : Screw B : Screw A
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CT-X870IN / VER.2
A-2. Place the digital keyboard with the keyboard facing up.
NOTE: The panel(s) and lower case are not secured at this point.
Hold the panel(s) with your hands when turning over the digital keyboard.
A-3. Lift the main panel and turn it over.
NOTE: The main panel and lower case are connected with cables. Use caution so as not to
apply too much tension to the cables when lifting the main panel.
NOTE: Mat a cushion material (cloth etc.) not to damage the keyboard before placing the
main panel.
Main panel Cushion material
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CT-X870IN / VER.2
Checking the Main Panel Type and Attaching the Spacer
• There are three types of the power terminal opening (on the reverse side) of the main panel.
For Type A, attach the spacer (SHEET/V-ZERO) the same way as Type B.
No spacer is necessary for Type C.
Type A Type B Type C
Spacer
Rib
(SHEET/V-ZERO)
<Spacer Position>
Code No. Parts Name Specifi cation Q’ty Remarks
10609381 SHEET/V-ZERO RJM517844-001V01 2 Black
• Fig. 1: Attach the spacer at 0 to 1.0 mm from the edge of the terminal opening.
• Fig. 2: Position the spacer against the bottom surface of the lower case.
Fig. 1 Fig. 2
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CT-X870IN / VER.2
Notes on Assembly
• When any of lead wires is replaced, arrange the lead wires to the rib of lower case and
bundle the 6 lead wires with SPONGE/50X260.
* For the affi xing position of sponge, refer to the rib of lower case shown in the fi gure below.
Rib
SPONGE/50X260
• Before assembling the main panel, check the knot of cable tie that fi xes lead wires to PSA1
PCB is in the correct direction.
– The knot should be laterally facing the PCB.
* If the main panel is closed while the knot faces upward, it interferes with the keyboard
and the main panel may fl oat.
• Fig. 1: Before assembling the main panel, arrange ribbon cables (x3) as shown in the fi gure
below and bundle them with a cable tie.
Fold and tuck an excess length of the pitch bend cable under the KYA PCB cable
Hold the ribbon cables with a clip
Fold the ribbon cables upward (approx. 90 degrees)
• Fig. 2: When assembling the main panel, hold the cables shown in the red frame in the fi gure
below by hand and close the main panel.
Fig. 1 Fig. 2
: Cable tie
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B. Removing the Main Panel
B-1. Unsolder to disconnect the following cables and remove the main panel.
NOTE: Release the ribbon cables from the clip.
MEMO: The lead wires are fi xed to the hole of PSA1 PCB with a cable tie.
Cable / Remarks Connected From
CT-X870IN / VER.2
: Cable tie
2 lead wires From the left: White, green Left speaker
2 lead wires From the left: Black, red Battery springs
2 lead wires From the left: Blue, brown Right speaker
Ribbon cable 3-pin Pitch bend
Ribbon cable 13-pin (PCB: 14 pads) KYA1 PCB
Ribbon cable 11-pin (PCB: 15 pads) KYA2 PCB
Clip
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CT-X870IN / VER.2
C. Removing the Side Panel
C-1. Undo 2 screws (S4).
C-2. Remove the side panel cables from the rib of lower case and remove left side panel or right
side panel.
To completely remove the side panel, refer to the next page.
: S4 : Rib
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Left Side Panel
(1) Unsolder to disconnect the following cables.
NOTE: Release the cables from the cable tie and clip.
NOTE: Remove the cables from the rib of lower case.
MEMO: The lead wires are bundled with sponge tape.
(2) Undo 1 screw and remove the FERRITE CORE.
Cable / Remarks Connected From
CT-X870IN / VER.2
2 lead wires From the left: White, green PSA1 PCB
Ribbon cable 3-pin MDA1 PCB
: Cable tie
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Right Side Panel
(1) Unsolder to disconnect the following cable.
NOTE: Remove the cable from the rib of lower case.
MEMO: The lead wires are bundled with sponge tape.
FERRITE CORE Clip
: Cable tie : Screw
: Cable tie
Cable / Remarks Connected From
2 lead wires From the left: Blue, brown PSA1 PCB
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D. Removing the PCB UNIT/MAIN
D-1. Unsolder to disconnect the following cables.
Cable / Remarks Connected From
CT-X870IN / VER.2
D-2. Undo 3 screws and remove the PCB UNIT/MAIN.
Ribbon cable 3-pin Pitch bend
Ribbon cable 13-pin (PCB: 14 pads) KYA1 PCB
Ribbon cable 11-pin (PCB: 15 pads) KYA2 PCB
Ribbon cable 10-pin PSA1 PCB
Ribbon cable 15-pin (PCB: 18 pads) PSA1 PCB
Ribbon cable 13-pin PSA1 PCB
PCB UNIT/MAIN
: Screw
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CT-X870IN / VER.2
E. Removing the BACK LIGHT UNIT
MEMO: BACK LIGHT UNIT is confi gured with PSA1 PCB, PSA2 PCB, and backlight component.
E-1. Unsolder to disconnect the following cables.
NOTE: Release the cables from the clip.
MEMO: BACK LIGHT UNIT (PSA1 PCB, PSA2 PCB) can be removed without disconnecting
cable
, and cable , and cable .
Cable / Remarks Connected From
E-2. Undo 3 screw A and 1 screw B, and then remove the MDA1 PCB and FERRITE CORE (for
cable
FERRITE CORE
Ribbon cable 10-pin PSA1 PCB
Ribbon cable 15-pin (PCB: 18 pads) PSA1 PCB
Ribbon cable 13-pin PSA1 PCB
) from the PSA1 PCB.
Clip
MDA1
: Screw A : Screw B
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E-3. Unsolder to disconnect the following cables.
MEMO: The lead wires are fi xed to the hole of PSA1 PCB with a cable tie.
Cable / Remarks Connected From
CT-X870IN / VER.2
2 lead wires From the left: White, green Left speaker
2 lead wires From the left: Black, red Battery springs
2 lead wires From the left: Blue, brown Right speaker
PSA2 PSA1
: Cable tie
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CT-X870IN / VER.2
E-4. Undo 27 screws and then remove the BACK LIGHT UNIT (w/ FABRIC TAPE, PACKING,
KNOB, SPONGE (2 sheets)) , rubber keys (4 pcs.), and LCD.
MEMO: One screw is tightened with the clip.
NOTE: The LCD may be stuck on the BACK LIGHT UNIT.
Use caution when handling the BACK LIGHT UNIT to prevent the LCD from dropping.
E-5. Remove the KNOB from the PSA2 PCB.
PSA2 PSA1
: Screw
: Screw / Clip
LCDBACK LIGHT UNIT
A
D ECB
A: RUBBER BUTTON/A (for Power button)
B: KNOB
C: RUBBER BUTTON/A
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D: RUBBER BUTTON/B
E: RUBBER BUTTON/C
CT-X870IN / VER.2
Notes on Assembly
• When replacing the BACK LIGHT UNIT, attach PACKING/10X30 to PSA1 PCB as shown in
the fi gure below.
* Attach tha packing in accordance with silk-printed solid line (square bracket x2).
– For protect the ribbon cable from lead frame of backlight LED protruding from PCB
PACKING/10X30Lead frame
• When attaching the KNOB, push it to the back surely.
– The gap between knob (convex part) and PCB should be less than 1 mm
Reference: When setting the nob to max. sound volume, min. sound volume, or medium
sound volume position, 1 mm gap gauge should not be inserted at each position.
• Before assembling the BACK LIGHT UNIT, check the ribbon cable of PSA2 PCB is parallel to
the PCB.
* If the ribbon cable is fl oating, it may interfere with the rotation of knob.
• Before assembling the LCD, check that the LCD surfaces on the main panel side and LCD
side are free from dust and dirt.
• Be sure that the LCD is in the correct orientation when assembling.
• Tighten the screws at LCD part in the silk-printed order.
If not tightened correctly, it may cause LCD display errors.
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