Unit UT8806E User manual

Service Manual
UT8806E Desktop Digital Multimeter

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Preface
Thank you for choosing this brand new UNI-T instrument. In order to use this instrument safely and correctly,
please read this manual thoroughly, especially the Safety Requirements part.
After reading this manual, it is recommended to keep the manual at an easily accessible place, preferably
close to the device, for future reference.
Copyright
Copyright is owned by Uni-Trend Technology (China) Co., Ltd.
UNI-T products are protected by patent rights in China and other countries, including issued and pending
patents. Uni- Trend reserves the rights to any product specification and pricing changes.
Uni-Trend Technology (China) Co., Ltd. all rights reserved. Trend reserves all rights. Information in this
manual supersedes all previously published versions. No part of this manual may be copied, extracted or
translated by any means without the prior permission of Uni-Trend.
UNI-T is the registered trademark of Uni Trend Technology (China) Co., Ltd.
Warranty Service
The instrument has a warranty period of one year from the date of purchase. If the instrument is damaged
due to improper operation by the user during the warranty period, the maintenance fee and the costs caused
by the maintenance shall be borne by the user, and the instrument shall be maintained by the company for
life.
If the original purchaser sells or transfers the product to a third party within one year from the date of
purchase of the product, the warranty period of one year shall be from the date of the original purchase from
UNI-T or an authorized UNl-T distributor. Power cords, accessories and fuses, etc. are not included in this
warranty.
If the product is proved to be defective within the warranty period, UNI-T reserves the rights to either repair

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the defective product without charging of parts and labor, or exchange the defected product to a working
equivalent product (determined by UNI-T). Replacement parts, modules and products may be brand new, or
perform at the same specifications as brand new products. All original parts, modules, or products which
were defective become the property of UNI-T.
The "customer" refers to the individual or entity that is declared in the guarantee. In order to obtain the
warranty service, “customer “must inform the defects within the applicable warranty period to UNI-T, and
perform appropriate arrangements for the warranty service.
The customer shall be responsible for packing and shipping the defective products to the individualor entity
that is declared in the guarantee. In order obtain the warranty service, customer must inform the defects
within the applicable warranty period to UNI-T, and perform appropriate arrangements for the warranty
service. The customer shall be responsible for packing and shipping the defective products to the
designated maintenance center of UNI-T, pay the shipping cost, and provide a copy of the purchase receipt
of the original purchaser. If the products is shipped domestically to the purchase receipt of the original
purchaser. If the product is shipped to the location of the UNI-T service center, UNI-T shall pay the return
shipping fee. If the product is sent to any other location, the customer shall be responsible for all shipping,
duties, taxes, and any other expenses.
This warranty shall not apply to any defects or damages caused by accidental, machine parts’ wear and tear,
improper use, and improper or lack of maintenance. UNI-T under the provisions of this warranty has no
obligation to provide the following services:
a) Any repair damage caused by the installation, repair, or maintenance of the product by non UNI-T service
representatives.
b) Any repair damage caused by improper use or connection to an incompatible device.
c) Any damage or malfunction caused by the use of a power source which does not conform to the
requirements of this manual.
d) Any maintenance on altered or integrated products (if such alteration or integration leads to an increase
in time or difficulty of product maintenance).
This warranty is written by UNI-T for this product, and it is used to substitute any other express or implied
warranties. UNI-T and its distributors do not offer any implied warranties for merchant ability or applicability
purposes.
For violation of this guarantee, regardless of whether UNI-T and its distributors are informed that any
indirect, special, incidental, or consequential damage may occur, UNI-T and its distributors shall not be
responsible for any of the damages.

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1. Overview
Safety Information
This section contains information and warnings that must be followed to keep the instrument operating
under safety conditions. In addition, user should also follow the common safety procedures.
Safety Precautions
Warning
Please follow the following guidelines to avoid possible electric shock and risk to personal
safety.
Users must follow the following conventional safety precautions in operation, service and
maintenance of this device. UNI-T will not be liable for any personal safety and property loss
caused by the user’s failure to follow the following safety precautions. This device is designed
for professional users and responsible organizations for measurement purposes.
Do not use this device in any way not specified by the manufacturer. This device is only for
indoor use unless otherwise specified in the product manual.
Safety Statement
Warning
“Warning” indicates the presence of a hazard. It reminds users to pay attention to a certain
operation process, operation method or similar. Personal injury or death may occur if the rules
in the “Warning” statement are not properly executed or observed. Do not proceed to the next
step until you fully understand and meet the conditions stated in the “Warning” statement.
Caution
“Caution” indicates the presence of a hazard. It reminds users to pay attention to a certain
operation process, operation method or similar. Product damage or loss of important data
may occur if the rules in the “Caution” statement are not properly executed or observed. Do not
proceed to the next step until you fully understand and meet the conditions stated in the
“Caution” statement.
Note
“Note” indicates important information. It reminds users to pay attention to procedures,
methods and conditions, etc. The contents of the “Note” should be highlighted if necessary.
Safety Sign
Danger
“Danger” indicates the presence of a hazard. It reminds users to pay
attention to a certain operation process, operation method or similar.
Personal injury or death may occur if the rules in the “Danger” statement
are not properly executed or observed. Do not proceed to the next step
until you fully understand and meet the conditions stated in the “Danger”
statement.
Warning
“Warning” indicates the presence of a hazard. It reminds users to pay
attention to a certain operation process, operation method or similar.
Product damage or loss of important data may occur if the rules in the
“Warning” statement are not properly executed or observed. Do not

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proceed to the next step until you fully understand and meet the
conditions stated in the “Warning” statement.
Caution
It indicates possible danger, which may cause damage to this device or
other equipment if you fail to follow a certain procedure or condition. If
the “Caution” sign is present, all conditions must be met before you
proceed to operation.
Note
It indicates potential problems, which may cause failure of this device if
you fail to follow a certain procedure or condition. If the “Note” sign is
present, all conditions must be met before this device will function
properly.
AC
Alternating current of device. Please check the region’s voltage range.
DC
Direct current of device. Please check the region’s voltage range.
Grounding
Frame and casing cover grounding terminal
Grounding
Protective grounding terminal
Grounding
Measurement grounding terminal
CAT 0
This instrument is suitable for measurements on circuits that are not
directly connected to the grid power supply and circuits that are specially
protected to be powered from the (internal) grid. In the latter case, the
transient stresses are different, and the instrument should be used for
this type of measurement to ensure that the peak transient voltage is
less than and equal to 3000 V.
CAT Ⅰ
Secondary electrical circuit connected to wall sockets through
transformers or similar equipment, such as electronic instruments and
electronic equipment; electronic equipment with protective measures,
and any high-voltage and low-voltage circuits, such as the copier in the
office.
CAT Ⅱ
Primary electrical circuit of the electrical equipment connected to the
indoor socket via the power cord, such as mobile tools, home appliances,
etc. Household appliances, portable tools (e.g. electric drill), household
sockets, sockets more than 10 meters away from CAT III circuit or
sockets more than 20 meters away from CAT IV circuit.
CAT Ⅲ
Primary circuit of large equipment directly connected to the distribution
board and circuit between the distribution board and the socket (three-
phase distributor circuit includes a single commercial lighting circuit).
Fixed equipment, such as multi-phase motor and multi-phase fuse box;
lighting equipment and lines inside large buildings; machine tools and
power distribution boards at industrial sites (workshops).
CAT Ⅳ
Three-phase public power unit and outdoor power supply line equipment.
Equipment designed to “initial connection”, such as power distribution
system of power station, power instrument, front-end overload
protection, and any outdoor transmission line.
Certification
CE indicates a registered trademark of EU

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Certification
UKCA indicates a registered trademark of UK
Certification
Complies with UL STD 61010-1, 61010-2-030 and CSA STD C22.2 No.
61010-1 and 61010-2-030
Waste
Do not put the equipment and accessories in the trash. The wasted items
must be properly disposed of in accordance with local regulations.
EFUP
This environment-friendly use period (EFUP) mark indicates that
dangerous or toxic substances will not leak or cause damage within this
indicated time period. The environment-friendly use period of this
product is 40 years, during which it can be used safely. Upon expiration
of this period, it should enter the recycling system.
Warning
The UT8806E Desktop Digital Multimeter only supports measurement of power supplies
under CAT II (600V) type overvoltage conditions, so please use the instrument strictly in
accordance with this measurement environment.
Safety Requirements
Warning
Preparation
before use
Please connect this device to AC power supply with the power cable provided.
The AC input voltage of the line reaches the rated value of this device. See the product
manual for specific rated value.
The line voltage switch of this device matches the line voltage.
The line voltage of the line fuse of this device is correct.
It is not used to measure the main circuit.
Check all
terminal rated
values
Please check all rated values and marking instructions on the product to avoid fire and
impact of excessive current. Please consult the product manual for detailed rated
values before connection.
Use the power
cord properly
You can only use the special power cord for the instrument approved by the local and
state standards. Please check whether the insulation layer of the cord is damaged or
the cord is exposed, and test whether the cord is conductive. If the cord is damaged,
please replace it before using the instrument.
Instrument
Grounding
To avoid electric shock, the grounding conductor must be connected to the ground.
This product is grounded through the grounding conductor of the power supply. Please
be sure to ground this product before it is powered on.
AC power
supply
Please use the AC power supply specified for this device. Please use the power cord
approved by your country and confirm that the insulation layer is not damaged.

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Electrostatic
prevention
This device may be damaged by static electricity, so it should be tested in the anti-
static area if possible. Before the power cable is connected to this device, the internal
and external conductors should be grounded briefly to release static electricity. The
protection grade of this device is 4 kV for contact discharge and 8 kV for air discharge.
Use the input /
output port of
this device
properly
Please use the input / output ports provided by this device in a properly manner. Do not
load any input signal at the output port of this device. Do not load any signal that does
not reach the rated value at the input port of this device. The probe or other
connection accessories should be effectively grounded to avoid product damage or
abnormal function. Please refer to the product manual for the rated value of the input /
output port of this device.
Power fuse
Please use power fuse of specified specification. If the fuse needs to be replaced, it
must be replaced with another one that meets the specified specifications by the
maintenance personnel authorized by UNI-T.
Disassembly
and cleaning
There are no components available to operators inside. Do not remove the protective
cover.
Maintenance must be carried out by qualified personnel.
Service
environment
This device should be used indoors in a clean and dry environment with ambient
temperature from 0℃to +40℃.
Do not use this device in explosive, dusty or humid air.
Do not operate
in moisture
environment
To avoid the risk of short circuit or electric shock in the internal circuit of the
instrument. Do not operate the instrument in humid environment.
Do not operate
in flammable
and explosive
environment
Do not use this device in a flammable and explosive environment to avoid product
damage or personal injury.
Caution
Abnormality
If this device may be faulty, please contact the authorized maintenance personnel of
UNI-T for testing. Any maintenance, adjustment or parts replacement must be done by
the relevant personnel of UNI-T.
Cooling
Do not block the ventilation holes at the side and back of this device;
Do not allow any external objects to enter this device via ventilation holes;
Please ensure adequate ventilation, and leave a gap of at least 15 cm on both sides,
front and back of this device.
Safe
transportation
Please transport this device safely to prevent it from sliding, which may damage the
buttons, knobs or interfaces on the instrument panel.
Proper
ventilation
Poor ventilation will cause the device temperature to rise, thus causing damage to this
device. Please keep proper ventilation during use, and regularly check the vents and
fans.
Keep clean and
dry
Please take actions to avoid dust or moisture in the air affecting the performance of
this device. Please keep the product surface clean and dry.
Note
Calibration
The recommended calibration period is one year. Calibration should only be carried out
by qualified personnel.

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Environmental Condition
This instrument is suitable for the following environment.
Indoor use
Pollution degree 2
In operating, the altitude should lower than 3000 meters; in non-operating, the altitude should lower
than 15000 meters
Unless otherwise specified, operating temperature is 10 to +40℃; storage temperature is -20 to﹢70℃
In operating, the humidity temperature should below to +35℃, and the relative humidity should ≤90％In
non-operating, the humidity temperature should within +35℃to +40℃, and the relative humidity
should relative humidity ≤60％
There are ventilation opening on the rear panel and side panel of the instrument. So please keep the air
flowing through the vents of the instrument housing. Make sure that the vent of the first instrument is away
from the air exhaust of the other instruments. If air heated by an instrument flows to the second
instrument, it may cause the second instrument to operate in over-temperature or even malfunction.
To prevent excessive dust from blocking the vents, please clean the instrument housing regularly. The
housing is not waterproof, please disconnect the power supply first and then wipe the housing with a dry
cloth or a slightly moistened soft cloth.
Connecting Power Supply
AC power specification is AC 100～240V 50/60Hz.
Please use the attached power lead to connect to the power port.
Connecting to service cable
This instrument is a Class I safety product. The supplied power lead has good performance in terms of case
ground. This spectrum analyzer is equipped with a three-prong power cable that meets international safety
standards. It provides good case grounding performance for the specification of your country or region.
Please connecting AC power cable as the following steps.
Ensure the power cable is in good condition
Leave enough space for connecting the power cord
Plug the attached three-prong power cable into a well-grounded power socket.
Voltage Range
Frequency
100-240VAC（fluctuant ±5%）
50/60/240Hz

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Electrostatic Protection
Electrostatic discharge may cause damage to component. Components can be damaged invisibly by
electrostatic discharge during transportation, storage and use.
The following measure can reduce the damage of electrostatic discharge.
Testing in anti-static area as far as possible
Before connecting the power cable to the instrument, inner and outer conductors of the instrument
should be briefly grounded to discharge static electricity
Ensure all the instruments are properly grounded to prevent the accumulation of static
Serial Number and System Information
UNI-T continually improves the performance, availability, and reliability of its products. UNI-T service
personnel have access to check the serial number and system information.
The serial number is located on the serial label on the rear cover, or if the instrument is powered on, press
the [System] key -> "INFO" to view. System information is useful for updates and aftermarket upgrades.

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2. Introduction
Supporting Product
This manual covers servicing the following products:
UT8806E check for a specific product name in the header, title, table or chart title or text at the top of the
page. Material without any specific product name applies to all products in the manual.
Operation Information
The instrument information of installation, operation and remote control see User’s Manual.
3. Structure
Rear Module
Accessory List
No.
Article
Description
1
KM3X8 quincunx
screw
Use T10 quincunx screwdriver to remove 4 screws
2
GPIB hexagonal
screw
Use 5.5 hexagonal screwdriver or needle-nose pliers to remove 2
screws
3
Rear cover
4
Product body

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Handle
Accessory List
No.
Article
Description
1
Handle
Pull the handle to both sides by slightly force, rotate vertically along the
direction of the host panel to the top of the machine, and then pull away
on both sides
2
Frame
component

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Outer Frame
Accessory List
No.
Article
Description
1
KM3X8 quincunx
screw
Use T10 quincunx screwdriver to remove 2 screws
2
Outer frame
Pull to the back of the case
3
Fuse cover
Take it down
4
Product body
Rear Panel
Accessory List
No.
Article
Description
1
KM3X6 quincunx screw
Use T10 quincunx screwdriver to remove 4 screws
2
KM3X7 quincunx screw
Use T10 quincunx screwdriver to remove 2 screws
3
PM3X6 quincunx machine
screw
Use T10 quincunx screwdriver to remove 1 screw
4
Rear panel
Pull to the back of the case
5
Product body

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Control Board
Accessory List
No.
Article
Description
1
KM3X7 quincunx screw
Use T10 quincunx screwdriver to remove 2 screws
2
KM3X6 quincunx screw
Use T10 quincunx screwdriver to remove 4 screws
3
PB3X7 quincunx self-
tapping screw
Use T10 quincunx screwdriver to remove 4 screws
4
Front panel
5
PB2X8 quincunx self-
tapping screw
Use T6 quincunx screwdriver to remove 9 screws
6
Control PCB
7
Function key
8
LCD module
9
Control key
10
Surface cover
11
Product body

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Product Body
Accessory List
No.
Article
Description
1
PM3X6 quincunx machine screw
Use T10 quincunx screwdriver to remove 7 screws
2
PM3X8 quincunx machine screw
Use T10 quincunx screwdriver to remove 1 screw
3
Hexagonal flange nut _4X0.7
Use needle-nose pliers to clamp 2 screws
4
CM4X8 quincunx short-head
machine screw
Use T8 quincunx screwdriver and needle-nose pliers to
remove 2 screws
5
PB4.0X10 quincunx countersunk
head self-tapping screw
Use T20 quincunx screwdriver to remove 4 screws
6
m3X35 hexagonal stud
7
Input socket
8
Input socket switching
Pull out along the surface cover
9
GPIB module
10
Upper cover of shielding case
11
Protective cover of fuse
Pull it down by hand
12
Upper cover of shielding case
13
Inner frame

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4. Maintenance
This section contains the information needed to do periodic and corrective maintenance on the
instrument.
ESD Prevention
Before servicing this product, read the General SafetySummary and the Service Safety Summary at the front
of the manual, as well as the following ESD information.
Caution: Electrostatic discharge (ESD) can damage any semiconductor component in this
instrument.
When performing any service that requires internal access to the instrument, adhere to the following
precautions to avoid damaging internal modules and their components due to electrostatic discharge.
1. Minimize handling of static-sensitive circuit boards and components.
2. Transport and store static-sensitive modules in their static protected containers or on a metal rail.
Label any package that contains static-sensitive boards.
3. Discharge the static voltage from your body by wearing a grounded antistatic wrist strap while
handling these modules.
4. Service static-sensitive modules only at a static-free work station.
5. Do not allow any items capable of generating or holding a static charge on the work station surface.
6. Handle circuit boards by the edges when possible.
7. Do not slide the circuit boards over any surface.
8. Avoid handling circuit boards in areas that have a floor or work-surface covering capable of generating
a static charge.
Inspection and Cleaning
Inspection and cleaning describes how to inspect for dirt and damage. It also describes how to cleanthe
exterior and interior of the instrument. Inspection and cleaning are the preventive maintenance. Regularly
preventive maintenance can prevent malfunction and enhance its reliability.
Preventive maintenance consists of visually inspecting and cleaningthe instrument and using general care
when operating it.
The frequency of performing maintenance depends on the severity of the environment in which the
instrument is used. The appropriate time to perform preventive maintenance is before the instrument is
adjusted.

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Exterior Cleaning
Clean the exterior surfaces of the chassis with a dry lint-free cloth or a soft-bristle brush. If any dirt
remains, use a cloth or swab dipped in a 75% isopropyl alcohol solution. Use a swab to clean narrow spaces
around controls and connectors. Do not use abrasive compounds on any part of the chassis that may
damage the chassis.
Caution：Avoid the use of chemical cleaning agents which might damage the plastics used in this
instrument.
Use only deionized water when cleaning the front-panel buttons. Use a 75% isopropyl
alcohol solution as a cleaner for cabinet parts. Before using any other type of cleaner,
consult UNI-T Service Center or representative.
Appearance Inspection Inspect the outside of the instrument for damage, wear, and missing parts.
Immediately repair defects that could cause personal injury or lead to further
damage to the instrument.
External Inspection Checklist
Item
Inspect
Repair Action
Cabinet, front panel, input port
Cracks, scratches, deformations,
damaged hardware
Repair or replace defective modules
Rotary knon on front panel
The knob is missing, damaged or
loose
Repair or replace missing or
defective knobs
Connection
Broken shells, cracked insulation,
and deformed contacts
Dirt in connectors
Repair or replace defective modules
Clear or brush out dirt
Carrying handle and support leg
Correct operation
Repair or replace defective modules
Accessories
Missing items or parts of items,
bent pins, broken or frayed cables,
and damaged connectors
Repair or replace damaged or
missing items, frayed cables, and
defective modules
Screen Cleaning
Please use wet tissue or a soft cloth to wipe the dust from the screen and surface.
If the display screen is very dirty, please use a cloth to dipped in distilled water, 75% isopropyl alcohol
solution or glass cleaner to slightly wipe the sceen surface. Only use enough water to wet the cloth or to
wipe. Please do not use excessive force, which may damage the display surface.
Caution：Improper cleaner and cleaning way will cause damage to the screen.
Do not use abrasive cleaner or surface cleaner to clear the LCD.
Do not directly spray water on the LCD surface.
Do not excessive force to wipe the LCD.
Caution：To prevent moisture inside the instrument during external cleaning, do not spray any
cleaning solution onto the screen or instrument directly.

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Return Instrument to Maintenance
Use the original package to repack the instrument for shipping. If the package is not applicable, please
contact the local UNI-T representative for a new packing.
Use industrial stapler or strapping tape to seal the carton.
If the instrument is being shipped to a UNI-T Service Center, enclose the following information.
The owner’s address
Name and phone number of a contact person
Model and serial number of the instrument
Reason for returning
A complete description of the service request
Mark the address of the UNI-T Service Center and also your own return address on the shipping carton in two
prominent locations.

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5. Replacement
Disassembly/Replacement Tool
Use the tool is shown in the following table to replace the module of the digital power meter.
No.
Tool Name
Description
1
Quincunx
screwdriver
The model refers to the removal steps
2
Soft pad
For protect the screen and rotary knob when removing rear modules
3
ESD prevention
To prevent static damage to the components while working on the
instrument, wear properly grounded anti-static wristbands and foot
bands, and use anti-static pads in a tested anti-static environment
Replace Small Current Fuse
Explanation
This section can fix the two problems.
1) Replace the fuse
2) Supply voltage selection switching
1. Open the opening at the top of the power module to replace the small current fuse, as shown in the
following figure.

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2. Power fuse, as shown in the following figure.
3. Reverse execute the above step to reinstate.
Replace Handle
Explanation
This section describes how to remove and replace handle.
1. Rotating the handle to removal position and pull out by slightly force. If the handle is damaged, it can be
replaced by this procedure, as shown in the following figure.
2. Caution: Keep the instrument body upright and the handle should be is perpendicular to the body,
and then hidden hook be taken out from the instrument, as shown in the following figure.

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Remove Case and Replace 10A Fuse
Explanation
The following step is to replace 10A fuse.
Remove the bottom protective cover and replace the fuse, as shown in the following figure.
Remove and Replace Key Board
Explanation
The following operations can be used to disassemble the front panel, rear panel and outer frame; Remove
and repair the front panel.
1. Use T10 quincunx screwdriver to remove 4 screws securing the rear panel, as shown in the following
figure.
2. Use T10 quincunx screwdriver to remove 2 screws securing the outer frame, as shown in the following
figure.