Koki Holdings DS 18DEX Series User manual

PRODUCT NAME
18 V Cordless Driver Drill
Models
DS 18DE, DS 18DEX
*
*: Designed for operating in the USA and Canada only
TROUBLESHOOTING GUIDE -------------------------------------------------------------------------------------------- 1
REPAIR GUIDE ---------------------------------------------------------------------------------------------------------------- 2
1. Precautions on disassembly and reassembly ----------------------------------------------------------- 2
• Disassembly--------------------------------------------------------------------------------------------------- 2
• Reassembly --------------------------------------------------------------------------------------------------- 6
• Checking after reassembly ------------------------------------------------------------------------------- 14
• Tightening torque-------------------------------------------------------------------------------------------- 14
• Type of silicone rubber-------------------------------------------------------------------------------------14
• Lubrication points and type of lubricant---------------------------------------------------------------- 15
• No-load current ----------------------------------------------------------------------------------------------15
• Wiring diagram----------------------------------------------------------------------------------------------- 16
2. Precautions on disassembly and reassembly of the charger ----------------------------------------16
CONTENTS Page
D
Overseas Sales Management Dept.
CONFIDENTIAL
Dec. 2022
DS 18DE with BSL 1850MA battery attached

-1-
Trouble Possible cause Checking method Corrective action
Motor does
not run.
• Faulty connection
between switch
and connector
cable
• Check for connection between the DC-
speed control switch and the connector
cable. (See “1. Reassembly of the
power supply unit and its vicinity” on
page 6.)
• Insert the
connector cable
properly.
• Faulty attachment
of rotor magnets
• Check whether the magnets of the
rotor pinion ass’y are flush with the end
surface of the rotor core.
• Replace the rotor
pinion ass’y.
• DC-speed control
switch failure
• Check the condition of the board
surface for peeling silicone, missing
element, and any indication of being
dropped in the past.
• Check the condition of the metallic
terminal (pin) in the switch connector
for corrosion.
• Replace the DC-
speed control
switch.
• Stator controller
ass'y failure
• Check the condition of the board
surface for peeling urethane, missing
element, and any indication of being
dropped in the past.
• Replace the stator
controller ass’y.
Rotation
cannot be
reversed.
• Faulty connection
between switch
and connector
cable
• Check for connection between the DC-
speed control switch and the connector
cable. (See “1. Reassembly of the
power supply unit and its vicinity” on
page 6.)
• Insert the
connector cable
properly.
• Switch connector
failure
• Check the connector of the connector
cable for corrosion.
• Check the condition of the metallic
terminal (pin) in the switch connector
for corrosion.
• Replace the DC-
speed control
switch or the stator
controller ass’y.
• Faulty contact in
the switch
• Check the connector cable of the stator
controller ass’y and the switch
connector for any abnormality.
• Replace the DC-
speed control
switch.
Rotation
speed cannot
be increased
or changed.
• Stator controller
ass'y failure
• Check the condition of the board
surface for peeling urethane, missing
element, and any indication of being
dropped in the past.
• Replace the stator
controller ass’y.
• Faulty connection
between switch
and connector
cable
• Check for connection between the DC-
speed control switch and the connector
cable. (See “1. Reassembly of the
power supply unit and its vicinity” on
page 6.)
• Insert the
connector cable
properly.
• Switch connector
failure
• Check the connector of the connector
cable for corrosion.
• Check the condition of the metallic
terminal (pin) in the switch connector
for corrosion.
• Replace the DC-
speed control
switch or the stator
controller ass’y.
• Faulty contact in
the switch
• Check the connector cable of the stator
controller ass’y and the switch
connector for any abnormality.
• Replace the DC-
speed control
switch.
LED light does
not turn on.
• Stator controller
ass'y failure
• Turn on the switch and check whether
the LED light turns on using a fully
charged battery.
• Replace the stator
controller ass’y.
TROUBLESHOOTING GUIDE

-2-
WARNING: Always remove the battery from the main body before starting repair or maintenance
work. Because the tool is cordless, inadvertently activating the switch with the battery
left in the main body will start the motor rotating unexpectedly, and could cause serious
injury.
1. Precautions on disassembly and reassembly
[Bold] numbers in the description below correspond to the item numbers in the parts lists and exploded
assembly diagrams for the Models DS 18DE and DS 18DEX.
1. Removal of the hook ass’y
Remove the Truss Hd. Screw M4 (Black) [42] and the Hook Ass’y [41]. The Hook Ass’y [41] need not be
removed, but is removed here to facilitate disassembly work.
2. Removal of the tail cover and housing (A).(B) set
(1) Remove the two Tapping Screws (W/Flange) D3 x 16 (Black) [34] from the Tail Cover [35] and then
remove the Tail Cover [35].
(2) Remove the nine Tapping Screws (W/Flange) D3 x 16 (Black) [34] from the tool body. Hold Housing
(A).(B) Set [38] at its battery mount portion, and then gently open it.
(3) After opening Housing (A).(B) Set [38], lift up Clutch Dial (S) [4] to take out the built-in parts together
from the inside of Housing (A).(B) Set [38]. The built-in parts are the Gear Box Ass'y [3], Rotor Pinion
Ass’y [30], Pushing Button [37], Stator Controller Ass’y [29], Shift Knob [32], and Strap (Black) [44]
(Model DS 18DE only). Pull out the Gear Box Ass'y [3] from the Rotor Pinion Ass’y [30] attached to the
Stator Controller Ass’y [29].
NOTE: The Rotor Pinion Ass’y [30] is removed together with the stator because the rotor has
strong magnetic force.
3. Disassembly of the gear unit
• Disassembly of the gear box ass'y and hand-clamping mechanism
(1) Turn the Motor Spacer [28] counterclockwise and remove it from the Gear Box Ass'y [3]. Remove the
Shift Arm [10].
NOTE: Be careful not to deform the Shift Arm [10] by applying excessive force to it.
(2) Turn Washer (B) [27] mounted in the Gear Case [11] counterclockwise and remove it. Then, take out
the First Ring Gear [26], Planet Gear (A) Set (4 pcs.) [25], Pinion (B) [24], Planet Gear (B) Set (4 pcs.)
[23], Pinion (C) [22], and Slide Ring Gear [21] in this order.
(3) Push Needle Roller (A) Set D2.2 (2 pcs.) [12] with a thin pin and pull it out from the other side of the
Gear Case [11]. Then, take out the Shift Dog [20], Planet Gear (C) Set (5 pcs.) [19], Carrier [18], Ring
Gear [17], six Steel Balls D5 [16], four Rollers [15], Lock Ring [14], and Washer (B) [13] in this order
from the inside of the Gear Case [11].
NOTE: Because the parts are very small, be careful not to lose them. Pay particular attention to
the four Rollers [15] and six Steel Balls D5 [16] that may easily roll away.
Disassembly
REPAIR GUIDE

-3-
4. Removal of the drill chuck
(1) Clamp the width-across-flats portion of the J-387 spindle lock jig (Code No. 370146) by using a vise.
Insert the Spindle [9] into the square hole of the J-387 spindle lock jig. Fully open the jaws of the Drill
Chuck [2] and turn the Hexalobula Screw (Left Hand) M6 [1] clockwise to remove it.
NOTE: The Hexalobula Screw (Left Hand) M6 [1] is a left-hand screw.
(2) Insert an M10 hex. bar wrench in the Drill Chuck [2], and then turn the wrench counterclockwise to
remove the Drill Chuck [2]. Use a pipe or other means of leverage in case the Drill Chuck [2] is difficult
to loosen
.
NOTE: • To remove the Drill Chuck [2], high torque is required because adhesive was applied to
the internal thread portion of the Drill Chuck [2]. Be sure to follow the above steps to
remove the Drill Chuck [2]. Do not hold the tool main body directly to remove the Drill
Chuck [2]. If doing so, the Lock Ring [14] may be damaged.
• Remove adhesive hardened on the internal threaded portion of the Drill Chuck [2] and
the external threaded portion of the Spindle [9] using a precision screwdriver completely
when reusing the removed the Drill Chuck [2] and Spindle [9].
5. Disassembly of the clutch mechanism
(1) Remove the Click Spring [5] from the Gear Box Ass'y [3].
NOTE: If it is hard to remove, use pliers to pull out the Click Spring [5] without applying excessive
force.
(2) Turn the Nut [6] counterclockwise to remove it from the Gear Case [11]. Remove the Spring [7] and
Thrust Plate [8].
(3) The Spindle [9] is press-fitted in the Gear Case [11]. Support the Gear Case [11] and push the Spindle
[9] on the opposite side of its threaded portion with a hand press slowly to remove the Spindle [9].
NOTE: Do not disassemble the Spindle [9] and Gear Case [11].
• Removal of the drill chuck
M10 hex. bar wrench
J-387 spindle lock jig
(Code No. 370146)
[2]
[4]
Vise
Jaws
[9]

-4-
6. Removal of the rotor pinion ass’y
The Rotor Pinion Ass’y [30] has strong magnetic force. Firmly hold the stator (core) of the Stator Controller
Ass’y [29] and slowly push the ball bearing (opposite to the pinion) of the Rotor Pinion Ass’y [30] in “A”
direction as shown in the figure below.
NOTE: Be careful not to damage the fan.
• Removal of the rotor pinion ass’y
A
[30]
Stator (core)
[29]
Fan

-5-
• Disassembly of the power supply unit
Internal wire (red)
(Plus terminal "+")
7. Disassembly of the power supply unit
(1) Peel silicone off the connector of the DC-Speed Control Switch [39] with a flat-blade screwdriver. To
remove the connector cable of the Stator Controller Ass’y [29], pull the connector cable lightly in "A"
direction while pressing the claw of the connector.
NOTE: Be careful not to scratch the connector of the DC-Speed Control Switch [39] and the
connector cable when peeling off silicone.
(2) Remove the Battery Terminal [40] from the Stator Controller Ass’y [29]. To remove the faston terminal,
pull the internal wire in "B" direction while pressing the claw of the faston terminal.
Faston terminal
Claw
[40]
Controller
LED light
Connector cable
[29]
Internal wire ass’y
Pull out the connector
cable while pressing the
claw of the connector.
Internal wire (black)
Internal wire (white)
Internal wire (red)
Connector
B
A
[39]
Internal wire (black)
(Minus terminal "-")
Internal wire (white)
(LD terminal "LD")

-6-
• Inserting the internal wires into the battery terminal
Internal wire (red)
(Plus terminal)
Generally perform reassembly by reversing the disassembly procedure. However, special attention should
be given to the following items.
1. Reassembly of the power supply unit and its vicinity
(1) Insert the Battery Terminal [40] into the Stator Controller Ass’y [29] until the faston terminal clicks into
place.
• Insert the red internal wire into the portion marked with "+" on the Battery Terminal [40].
• Insert the black internal wire into the portion marked with "-" on the Battery Terminal [40].
• Insert the white internal wire into the portion marked with "LD" on the Battery Terminal [40].
• After inserting the internal wires, check that the internal wires are securely connected by pulling the
internal wires lightly.
(2) Pay attention to the following when connecting the DC-Speed Control Switch [39].
• Insert the connector cable into the connector as far as it will go.
• Align the red line on the connector cable parallel to the connector when inserting the connector cable.
• After inserting the connector cable into the connector, apply silicone (ThreeBond TB1211) to the
connector entirely.
• Do not carry the Stator Controller Ass’y [29] by holding the connector cable. Do not pull the connector
cable.
(3) Push the internal wire ass’y and each internal wire of the Stator Controller Ass’y [29] in the guide grooves
of housing (A) securely to prevent the internal wires from being caught between housings (A) and (B).
(4) Put the connector cable between the screw bosses of housing (A) securely to prevent the connector
cable from being caught between housings (A) and (B).
(5) Fit the protrusion of the direction selector lever on the top of the DC-Speed Control Switch [39] into the
hole on the Pushing Button [37] and mount it to housing (A).
NOTE: If the contacts of the Battery Terminal [40] with the battery are covered with black oxide
or not plated, the contacts may heat up, possibly resulting in breakdown of the battery or
the tool main body. In such a case, replace the Battery Terminal [40] with new one.
Reassembly
+
- LD
Marking on [40]
Internal wire (black)
(Minus terminal)
Internal wire (white)
(LD terminal)
[40]

-7-
• Application of silicone to the connector
• Reassembly of the power supply unit and its vicinity (1)
Connector cable
LED light
Apply silicone to the connector entirely.
Connector cable
Check whether black oxide or separated
plating is found on the contacts or not.
Controller
Connector
****DS 18DE**
Internal wire ass’y
Internal wire (black)
Internal wire (white)
Internal wire (red)
[29]
[39]
Push in the
connecto
r
lightly.
[39]

-8-
• Reassembly of the power supply unit and its vicinity (2)
Internal wire guide groove
Put the internal wire ass’y and connector cable
to the right of the central rib of housing (A).
Fit the protrusion of the direction selector leve
r
on the top of the DC-Speed Control Switch [39]
into the hole of the Pushing Button [37].
Internal wires
(red, white, and black)
Insert the internal wire ass’y into the
internal wire guide groove first, then
insert the red, white, and black internal
wires into the internal wire guide groove.
[39]
Connector cable
Housing (A)
Internal wire ass’y
Put the red, white, and black
internal wires to the left of
the central rib of housing (A).

-9-
• Reassembly of the clutch mechanism
[4]
2. Reassembly of the gear unit
(1) Reassembly of the clutch mechanism
• Apply an appropriate amount of grease to the Spindle [9] according to “Lubrication points and type of
lubricant” on page 15.
• Mount the Spindle [9] to the Gear Case [11] and support the Gear Case [11]. Use the J-392 BB. press
fit jig (Code No. 371218) to press-fit the outer ring of the ball bearing of the Spindle [9] into the Gear
Case [11].
• Mount the Thrust Plate [8], Spring [7], and Nut [6]. Mount the Nut [6] to the Gear Case [11] as shown
in (A) and (B) of the figure "Mounting the nut" on page 10 and then turn the Nut [6] clockwise by a half
turn to secure it in place as shown in (C).
(2) Mounting clutch dial (S)
• Insert the convex portion of the Click Spring [5] into the groove of the Gear Case [11] according to the
figure "Mounting the click spring" on page 10.
• Mount the Nut [6] to Clutch Dial (S) [4] aligning the ribs of Clutch Dial (S) [4] with the grooves of the Nut
[6] according to the figure "Mounting clutch dial (S)" on page 10.
(3) Mounting the drill chuck
• Hold the Spindle [9] using the J-387 spindle lock jig (Code No. 370146) as shown in the figure on page
3.
• Insert an M10 hex. bar wrench into the Drill Chuck [2] and turn the wrench to tighten the Drill Chuck [2].
• Remove the M10 hex. bar wrench and turn the Hexalobula Screw (Left Hand) M6 [1] counterclockwise
to tighten. There is no need to apply adhesive to the internal threaded portion of the Drill Chuck [2] and
external threaded portion of the Spindle [9].
[5]
[8]
[6]
[7]
[9]
[11]
J-392 BB. press fit jig
(Code No. 371218)
[9]
[11]
Outer ring of the ball bearing

-10-
• Mounting the nut
Convex portion
(
A
)
(
B
)
(
C
)
Concave portion (2 places)
[7]
[8]
[11]
[6]
[5]
[11]
[6]
Grooves
Grooves
Ribs
[4]
Groove
• Mounting the click spring
• Mounting clutch dial (S)
Ribs
Mount the Nut [6]
and rotate it a half
turn clockwise.

-11-
• Reassembly of the hand-clamping mechanism
• Reassembly of the gear box ass'y
(4) Reassembly of the hand-clamping mechanism
Mount Washer (B) [13], Lock Ring [14] and four Rollers [15] in the Gear Case [11] in this order.
NOTE: Fit the convex portions of the Lock Ring [14] in the concave portions of the Gear Case [11].
(5) Reassembly of the gear box ass'y
• Apply an appropriate amount of grease to each gear according to “Lubrication points and type of lubricant”
on page 15.
• Mount the parts from the six Steel Balls D5 [16] to Washer (B) [13] in series to the assembly reassembled
in the above “(4) Reassembly of the hand-clamping mechanism.”
NOTE: • The Ring Gear [17], Carrier [18], Shift Dog [20], Slide Ring Gear [21], Pinion (C) [22], and
Pinion (B) [24] all have a specific orientation as shown in the figure below.
[11]
[14]
[13]
[15] (4 pcs.)
[21]
[14]
[15] (4 pcs.)
[17]
[19] (5 pcs.)
[18]
[22]
[24]
[25] (4 pcs.)
[26]
[27]
[28]
[11]
Convex portion
[15] (4 pcs.)
[14]
[9] [13]
[11]
[13]
[16] (6 pcs.)
[20]
[23] (4 pcs.)

-12-
• Mounting washer (B) to the gear case
• Mounting the shift arm
• After mounting the Shift Dog [20], insert Needle Roller (A) Set D2.2 (2 pcs.) [12] into the Gear Case [11].
• Fit the convex portion of Washer (B) [27] into the concave portion of the Gear Case [11], and then turn
Washer (B) [27] clockwise viewing from the rotor side until it contacts the Gear Case [11].
3. Reassembly of the drive unit
(1) Hook the loops of the Shift Arm [10] on the convex
portions of the Gear Case [11]. Check that both ends
of the Shift Arm [10] are put in the grooves of the Slide
Ring Gear [21] built in the Gear Case [11].
NOTE: The Shift Arm [10] has a specific orientation.
(2) Fit the claw of the Motor Spacer [28] in the concave
portion of the Gear Case [11]. Turn the Motor Spacer
[28] clockwise viewing from the rotor side until it
contacts the Gear Case [11].
4. Reassembly of housing (A).(B) set
(1) Apply an appropriate amount of grease to the two Rear Bumpers [36] according to “Lubrication points
and type of lubricant” on page 15.
(2) Insert the two Rear Bumpers [36] into housings (A) and (B).
(3) Mount the reassembled power supply unit, gear unit, and drive unit in housings (A) and (B) with the
convex portions of the Gear Case [11] and the Motor Spacer [28] fitted in the concave portions of
housings (A) and (B).
Convex portions
[27]
[11]
Concave portions
[11]
[12]
Holes for [12] (2 places)
• Inserting needle roller (A) set into the gear case
Left-handed
[
11
]
[10]
[28]
Mounting direction of [10]

-13-
• Reassembly of housing (A).(B) set
(4) Check that the protrusion of the direction selector lever of the DC-Speed Control Switch [39] is correctly
put in the hole of the Pushing Button [37].
(5) Fit the Shift Arm [10] in the groove of the Shift Knob [32] positioning the "2" marking on the Shift Knob
[32] at the rear.
(6) Mount the Strap (Black) [44] (Model DS 18DE only) to housing (A).
(7) Put housings (A) and (B) together and fasten it with the nine Tapping Screws (W/Flange) D3 x 16 (Black)
[34].
5. Mounting the rotor pinion ass’y and tail cover
(1) Apply an appropriate amount of grease to the tooth surface of the Motor Pinion [31] according to
“Lubrication points and type of lubricant” on page 15.
(2) Press-fit the Rotor Pinion Ass’y [30] into Housing (A).(B) Set [38] from behind.
(3) Press-fit the Tail Cover [35] into Housing (A).(B) Set [38] and tighten the two Tapping Screws (W/Flange)
D3 x 16 (Black) [34].
(4) After reassembly, run the motor at low speed to check that the Rotor Pinion Ass’y [30] rotates smoothly.
NOTE: If the Rotor Pinion Ass’y [30] does not rotate smoothly, the gear is improperly engaged.
In such a case, mount the Rotor Pinion Ass’y [30] properly. If the stator of the Stator
Controller Ass’y [29] cannot be mounted to the housing properly, the core is out of
position or there is a gap between housings (A) and (B) at the upper part of the motor. In
such a case, mount the Stator Controller Ass’y [29] properly. Replace Housing (A).(B) Set
[38] with new one if the ribs on Housing (A).(B) Set [38] for holding the stator are deformed.
(5) After completing reassembly up to step (4), check that each marking on Clutch Dial (S) [4] from “1” to
drill mark “ ” is aligned with the triangle mark on Housing (A).(B) Set [38], and that Clutch Dial (S) [4]
rotates regularly. If number “1” or the drill mark “ ” on Clutch Dial (S) [4] is not properly aligned with
the triangle mark on Housing (A).(B) Set [38], the Nut [6] or other parts may be improperly mounted.
Mount Clutch Dial (S) [4] or other parts correctly as described in “Reassembly of the clutch mechanism”
on page 9. Check the operation of the Shift Knob [32]. Switch the Shift Knob [32] and make sure the
speed is correctly switched between HIGH and LOW. If the speed change is disabled or abnormal, the
Shift Knob [32] or other parts may not be properly mounted. Mount the Shift Knob [32] or other parts
correctly as described in “Reassembly of the gear box ass'y” on page 11 or “Reassembly of the drive
unit” on page 12.
6. Mounting the hook
Insert the Hook [43] into the groove at the bottom of the side of Housing (A).(B) Set [38] and fasten it with
the Truss Hd. Screw M4 (Black) [42]. The Hook [43] can be mounted on either side of the tool body.
Boss for mounting the Strap (Black) [44]
(Model DS 18DE only)
Insert the Rear Bumper [36] (2 places).

-14-
After reassembly, install the battery and check for operation of each component as follows.
(1) Checking for lighting of the LED light
Check that the LED light turns on while pulling the switch and automatically turns off in about ten seconds
when you release your finger from the switch.
(2) Checking for rotating direction of the drill chuck
Press the Pushing Button [37] and check that the Drill Chuck [2] rotates as indicated on the button.
When you press the “R” side of the Pushing Button [37], the Drill Chuck [2] turns clockwise as viewed
from the rear of the tool body.
(3) Checking for runout of the drill chuck
Check that runout of the Drill Chuck [2] is up to 0.8 mm under the following condition.
• Set a 12-mm dia. test bar in the Drill Chuck [2] and measure runout of the Drill Chuck [2] at a position
110 mm away from the tip of the Drill Chuck [2].
Item
No. Part name No. used
Tightening torque
N•m kgf•cm
[1] Hexalobula Screw (Left Hand) M6 1 4.41 ± 0.5 45 ± 5
[2] Drill Chuck 13VLRU-N (W/O Chuck Wrench) 1 29.4 ± 2 300 ± 20
[34] Tapping Screw (W/Flange) D3 x 16 (Black) 11 1.3 ± 0.3 13 ± 3
[42] Truss Hd. Screw M4 (Black) 1 1.8 ± 0.4 18 ± 4
Please purchase the following silicone rubber as necessary.
Item Registered part name Net weight Code No.
Three Bond 1211 Silicone rubber 100 g 306927
Checking after reassembly
Tightening torque
Type of silicone rubber

-15-
Apply an appropriate amount of grease to the following portions.
MOLUB-ALLOY 777-1
• Tooth surface of Planet Gear (C) Set [19] and five needle rollers on the Carrier [18] that support Planet
Gear (C) Set [19]
• Tooth surface of Planet Gear (B) Set [23] and four needle rollers on Pinion (C) [22]
• Tooth surface of Planet Gear (A) Set [25] and four needle rollers on Pinion (B) [24]
• Six protruded portions of the Ring Gear [17]
• Four needle rollers on the Carrier [18]
• Outer circumference of the O-ring of the Spindle [9]
• Mating portion between the Shift Arm [10] and Slide Ring Gear [21]
NIPPECO SEP-3A
• Tooth surface of the Motor Pinion [31]
• Entire circumference of two Rear Bumpers [36]
Please purchase the following grease as necessary.
Item Registered part name Net weight Code No.
MOLUB-ALLOY 777-1 Grease (Molub-Alloy No. 777-1) 75 g 75 g 375042
NIPPECO SEP-3A
Grease (SEP-3A) (100 g) 100 g 930035
Grease (SEP-3A) (2.5 kg) 2.5 kg 930038
The no-load current should be 5.5 ± 1.0 A (DC 19.8 V—equivalent to the voltage of a fully charged battery)
after no-load operation for 5 minutes in “1” (low speed) mode.
Lubrication points and type of lubricant
No-load current

-16-
• Wiring diagram
Connector cable
LED light
"2" indication
[40]
"1" indication
• Connecting diagram
Internal wire ass’y
LED light
Main PCB ass'y
DC-speed control switch
Battery terminal
Battery
Sensor PCB ass’y
Red Black Black Black Black Red Black
White
Black Red
Blue WhiteYellow
Red
Black
Red Black White
2. Precautions on disassembly and reassembly of the charger
Refer to the service manual for precautions on disassembly and reassembly of the chargers Model
UC 18YSL3, UC 18YFSL, and UC 18YKSL.
Wiring diagram
[29]
[32]
[4]
[3]
[37]
[30]
[44]
(Model DS 18DE only)
Controller
Internal wires (red, white, and black)
[39]