lg DLE8377WM, DLG8388WM, DLE8377NM, DLG8388NM, DLE7177WM Service Manual

www.LGEservice.com

DISCOVERY DRYER
TRAINING MANUAL

CAUTION!

READ THIS MANUAL CAREFULLY
BEFORE DIAGNOSING OR SERVICING THIS PRODUCT.

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Published April 2006 by LG Technical Support and Training

DRYER

IMPORTANT SAFETY NOTICE

The information in this training manual is intended for use by persons possessing an adequate background
in electrical equipment, electronic devices, and mechanical systems. In any attempt to repair a major
appliance, personal injury and property damage can result. The manufacturer or seller maintains no liability
for the interpretation of this information, nor can it assume any liability in conjunction with its use. When
servicing this product, under no circumstances should the original design be modified or altered without
permission from LG Electronics. Unauthorized modifications will not only void the warranty, but may lead to
property damage or user injury. If wires, screws, clips, straps, nuts, or washers used to complete a ground
path are removed for service, they must be returned to their original positions and properly fastened.

CAUTION

To avoid personal injury, disconnect the power before servicing this product. If electrical power is required
for diagnosis or test purposes, disconnect the power immediately after performing the necessary checks.
Also be aware that many household appliances present a weight hazard. At least two people should be
involved in the installation or servicing of such devices. Failure to consider the weight of an appliance could
result in physical injury.

ESD NOTICE

Some of the electronic components in appliances are electrostatic discharge (ESD) sensitive. ESD can
weaken or damage the electronics in these appliances in a manner that renders them inoperative or reduces
the time until their next failure. Connect an ESD wrist strap to a ground connection point or unpainted metal
in the appliance. Alternatively, you can touch your finger repeatedly to a ground connection point or
unpainted metal in the appliance. Before removing a replacement part from its package, touch the anti-static
bag to a ground connection point or unpainted metal in the appliance. Handle the electronic control
assembly by its edges only. When repackaging a failed electronic control assembly in an anti-static bag,
observe these same precautions.

REGULATORY INFORMATION

This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to
Part 15 if the FCC Rules. These limits are designed to provide reasonable protection against harmful
interference when the equipment is operated in a residential installation. This equipment generates, uses,
and can radiate radio frequency energy, and, if not installed and used in accordance with the instruction
manual, may cause harmful interference to radio communications. However, there is no guarantee that
interference will not occur in a particular installation. If this equipment does cause harmful interference to
radio or television reception, which can be determined by turning the equipment off and on, the user is
encouraged to try to correct the interference by one or more of the following measures: Reorient or relocate
the receiving antenna; Increase the separation between the equipment and the receiver; Connect the
equipment to an outlet on a different circuit than that to which the receiver is connected; or consult the
dealer or an experienced radio/TV technician for help.

COMPLIANCE

The responsible party for this device’s compliance is LG Electronics Alabama, Inc.; 201 James Record Road,
Huntsville, AL, 35824.

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Contents

Regulatory Notices 3
Contents 4
Introduction 6
Sensor Dry 7
Manual Dry 7
Gas Safety Page 8
Specifications 9
Accessories 10
Installation (of accessories) 10
Rack 10
Stacking Kit 11
Pedestal 13
Modem and Monitor 15
Electric Dryer 16
Pigtail 16
4-wire Connection 16
3-wire Connection 17
Gas Dryer 19
Piping 19
Dryer Cycle Chart 20
Component Test Procedures 21
Motor Diagram and Schematic 22
Safety Switches 25
Control and PCB Layout 26
Wiring Diagram 28
Diagnostic Test 29
Test 1 – 120 V AC Electrical Supply 30
Test 2 – Thermistor Test (Power Off) 33
Test 3 – Motor Test 34
Test 4 – Moisture Sensor Test 35
Test 5 – Door Switch Test 36
Test 6 – Heater Switch Test (Electric Dryer) 37
Test 7 – Gas Valve Test (Gas Dryer) 38
Test 8 – Semiconductor Test 39
Gas Conversion (Natural to Propane) 40
Safety Warning 40
Orifice 41
Gas Valve Operation 42
Flow Chart 42
Ignition Sequence 42

continued on next page Æ

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Contents, continued

Disassembly/Repair 43
Top Cover 43
Control Panel 44
Front Cover and Door 45
Door Reversal 45
Tub Front 46
Drum Assembly and Belt 46
Lamp 47

Filter Assembly and Moisture Sensor 49
Back Cover 49
Air Duct 50
Rollers 51
Blower and Housing 52
Exploded Views 53
Top Cover and Control Panel 53
Cabinet and Door 54
Drum and Motor (Electric Dryer) 55
Drum and Motor (Gas Dryer) 56
Parts List 57

Vent Replacement (Rear to side exhaust) 48

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INTRODUCTION

The DISCOVERY dryer is very similar to other LG dryers with the exception of
the LCD display on the control panel. The LCD display shows all the information
formerly indicated by LEDs but also allows for scrolling instruction.

When a cycle is selected, the
options are preset. They can be
overridden by changing them using
the option buttons.

Pressing the buttons cycles through
the available options. If an option is
not available for a particular cycle, it
is grayed out or not available for
selection. For example, the EXTRA
HOT wash is not available for the
DELICATE cycle.

The interior components remain the same: motor, belt, drum, and heat source
(gas or electric). The gas model can be refitted with an orifice to allow the use of
propane instead of natural gas. All such conversions and adjustments should be
performed by a licensed and certified gasfitter.

The DISCOVERY model also has an additional sensor in the exhaust stream to
detect the moisture level more accurately for better drying results.

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Models DLE7177WM and DLG7188WM use the LED indicator panel instead of
the newer LCD. The only difference is the type of display. The dryers function
identically. The main and display PCB (Printed Circuit Board) will carry a different

part number depending upon the type of display. Always order parts by model

number and serial number to ensure receiving the correct parts.

The drying cycle is shown
in the left window and the
time remaining is show in
the right. Feature
selections like DRY
LEVEL and BEEPER
volume are indicated by
LEDs on the panel.

The DISCOVERY line of dryers feature enhanced sensor drying. In addition to
the drying sensor in the tub near the filter, there is an additional sensor in the
exhaust stream to ensure the correct level of dryness is determined, from damp
dry to very dry. The dryer can also be set manually to dry at a particular heat
level and for a specified time.

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SAFETY

Check the local laws and regulations concerning the installation and connection
of gas. In most localities, it is illegal to connect gas piping, re-jet or adjust burners,
or repair gas-fired equipment unless you are licensed and certified so to do. It is
the servicer’s responsibility to comply with all such regulation.

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SPECIFICATIONS

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ACCESSORIES

DRYING RACK STACKING KIT PEDESTAL

The DRYING RACK is used to dry items that should not be tumbled, like
sweaters, tennis shoes, etc. It should be removed and stored when not in use.
The rack is included with the dryer. (See installation procedure, page xx.)

The STACKING KIT is used to stack a dryer on top of a matching washer.
(NEVER put a washer on top of a dryer!) The stacking kit should not be used in
situation where there is the possibility of excessive vibration and movement of
the washer, such as in a mobile home or an upper floor of a frame structure. The
stacking kit is available as an optional purchase. (See installation procedure,
page 11.)

The PEDESTAL can be used under either the washer or the dryer. It is possible
to stack a washer and dryer on a pedestal, but the dryer controls may be difficult
to reach and the possibility of vibration and movement is greater. The pedestal is
available as an optional purchase. (See installation procedure, page 13.)
Pedestals are available in heights of 7¼” and 13”.

INSTALLATION (RACK)

It’s simple!

Open the dryer door.

Put the rack in place.

Select RACK DRY (2
Press START.

Be sure the front of the rack is properly
situated in the notches on either side
of the filter. The back should rest on
the drum and allow the drum to rotate.

nd

button on right)

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INSTALLATION (Stacking Kit)

WARNING! Do not attempt this alone! At least two people are required to lift the
dryer and place it properly on top of the washer. Failure to observe this warning
could result in serious physical injury and damage to the appliances.

1. Place the washer on a solid,
even floor. If you plan to use a
pedestal, install it now before
going any further.

2. Peel the protective paper from
the adhesive tape on the side
bracket.

3. Fit the side bracket firmly to the
top plate using the adhesive
tape, as shown in the drawing.

4. Secure the bracket to the top
plate using a screw, as shown.

Repeat steps 2, 3, and 4 for the
other side.

5. Level the dryer on a firm solid
floor and lock down the
adjusters before placing it on top
of the washer. (See page xx.)

Lift the dryer on top of the
washer it toward the front of the
washer, as shown.

Slide the dryer all the way back
to the stop on the rail.

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INSTALLATION (Stacking Kit) continued

6. Install the front rail of the
stacking kit. Push the front rail
back against the stops on the
side brackets.

7. Insert a screw to attach the front
rail to the side bracket.

Repeat step 7 for the other side.

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INSTALLATION (Pedestal)

1. Remove the pedestal,
installation hardware, and
instructions from the shipping
container.

2. Level the pedestal on a solid,
flat, level floor. Lock down the
rear adjusters, but leave the
front ones free for now.

Set the dryer on the pedestal
and level it. Level it and lock
down all four adjusters on the
dryer.

Note which holes are for the

REAR FRONT

washer and which are for the
dryer. If you are stacking the
appliances, the washer should
be on the bottom.

For 27” Pedestals

(Washer, Dryer, and Combo)

3. Remove the protective paper
from the adhesive surface of the
bracket.

Be particularly careful, because when
this adhesive makes contact, there is
no adjustment possible.

NOTE: Some kits include two sets of
brackets (curved for the dryer and flat
(shown) for the washer.) Use the
correct bracket for your application.
(See next page.)

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INSTALLATION (Pedestal) continued

4. Holding the adhesive part of the
bracket away from the dryer,
insert the screws and get them
started.

Press the bracket onto the dryer
and tighten the screws.

5. Press the brackets onto the
sides of the dryer and rub the
brackets from side to side to
ensure the total adhesive area is
attached completely.

6. Tighten all the screws securely.

7. Lower each leg of the dryer one­ fourth turn with the adjusting
wrench to put a little pressure
between the dryer and pedestal
to prevent any motion and
rattling.

8. Push the dryer into place.

9. Check the level and adjust the
front legs of the pedestal as
necessary. Then lock down the
adjusters.

The pedestal kit includes the mounting
plates (with adhesive covered by
paper) and the screws to attach the
plates. Remember, some pedestal kits
come with two sets of brackets. The flat
tops are for washers; the curved tops
(shown) are for dryers. Use the correct
brackets for your application.

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INSTALLATION (Modem and Monitor)

The monitor plugs in to any 110 Volt
outlet in the home. It receives its data
signal via the power lines.

1. Be sure the dryer is unplugged.

Remove the modem cover.

Save the cover for future use; in
the event you must remove the
modem, you can replace the
cover.

REMOTE MONITOR

2. Attach the modem to the socket
with the screws provided.

3. Plug the monitor’s power cord
in an outlet where you can
observe it easily. Use the stand
or the wall mount bracket.

4. Press and hold the button until

the display shows SET.

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ELECTRICAL CONNECTION (Electric Dryer Only)

PIGTAIL INSTALLATION

Install the appropriate power cord for the outlet available. Grounding through the
neutral conductor is prohibited in new branch-circuits, mobile homes, recreational
vehicles, and where prohibited by local code.

4-wire Connection

The 4-wire receptacle looks like this.

Power cord with spade terminals.

Power cord with ring terminals.

Install a strain relief on the power cord.

Then connect the terminals to the
terminal block, matching the wire
colors.

A. Ground screw on chassis
B. Green wire from power cord
C. Strain relief
D. Neutral screw on terminal block
E. Terminal block
F. Neutral wire from power cord

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ELECTRICAL CONNECTION (Electric Dryer Only) continued

3-wire Connection

The 3-wire receptacle looks like this.

Power cord with spade terminals.

Power cord with ring terminals.

Install a strain relief on the power cord.

Then connect the terminals to the
terminal block, matching the wire
colors. Add a wire to connect the
chassis ground to neutral.

A. Ground screw on chassis
B. Green wire from power cord
C. Strain relief
D. Neutral screw on terminal block
E. Ground-to-neutral connection
F. Neutral wire from power cord

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ELECTRICAL CONNECTION (Electric Dryer Only) continued

Be sure to tighten all screws firmly, but
do not strip them or distort the contact
area.

Be sure to install a strain relief on the
power cord.

Replace the terminal block cover by
inserting the tabs into the slots and
letting them slide down to engage.

Fold it over to the back of the dryer so
it covers the access to the terminal
block. Be sure no wires are exposed or
could touch any metal surface.

Secure the cover with a screw.

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