repair lcd

7/30/2019 repair lcd

1/23

1

1

7-Step Method for

Electronic Troubleshooting

Ken ReedSystem Improvements, Inc.

238 South Peters Road, Suite 301

Knoxville, Tennessee 37923 USA

Phone: 865-539-2139 Fax: 865-539-4335

e-mail: [email protected]

web: www.taproot.com

Copyright 2007 by System Improvements, Inc. All Rights Reserved. Duplication Prohibited.

Copyright 2007 by System Improvements, Inc., Knoxville, TN. All Rights Reserved Worldwide. Duplication Prohibited.

Scenario #1

You are enjoying a leisurely day by the pool.Man, its hot out here!

Your wife calls from the kitchen door. Thethermostat for the air conditioner is broke. Itsgetting hot in here!

Consequences: Stress and discomfort


2/23

2


Scenario #2

You are the maintenance supervisor at a coalmine. You must move 600 tons / hr out of themine.

You get a call from the control room. Theconveyor belt is down again. It just shut off.

You have about 1 hour before the hopper isempty and the rail cars are no longer being

filled. Consequences: $400,000 / hr.


Scenario #3

You are the Reactor Control Chief on anuclear submarine. You awaken when youhear all the ventilation fans turn off, and aloudspeaker announcement, ReactorScram.

The ship is currently operating under thenorth polar ice, with no place to surface within

6 hours. You have 3 ! hours left on battery power.

Consequences: Real ugly


3/23

3


Which is worse??

Fix it

NOW!!!


Ken Reed

Senior AssociateSystem Improvements


4/23

4


Who am I?

21 years Nuclear Submarine Experience

Retired Master Chief Electronics Technician

Served on: Ballistic Missile Boat

Fast Attacks

Nuclear Research sub

Last boat USS SEAWOLF


Electronic Troubleshooting

Topics:

Electronic vs Other Equipment

Before you start

Troubleshooting Methods

Organizing the Team

Seven Step Process


5/23

5


Note About This Presentation

I am going by my experience, which often dictatesa worst-case must fix scenario

If your needs are not this critical, take what youneed from what you see today


Troubleshooting Differences

Mechanical

Easier to see system

Can put your hands on it

Not much calculation

Often, small number ofalternatives

Electronic

Hard to visualize what apart does

Black boxes, miniaturized

May require extensivecalculation

Many directions to go


6/23

6


Troubleshooting Similarities

Requires knowledgeable troubleshooters

Systems becoming more complex

Lines blur between mechanical and electronic

Must always look at entire system interaction

Operators are ALWAYS breaking the gear!


Why Does Troubleshooting Fail??

No formalized process in place

No one in charge and looking at the Big Picture

No one knows initial conditions

No one is sure what has already been done

Everything performed in series

Pre-conceived idea of what caused problem


7/23

7


Before you start

Specify the goals of the troubleshooting

Have plan in place to:

Gather initial data

Notify team

Preserve the evidence / indications

Record troubleshooting progress / results


Organizing Your Team

Man in charge must be:

Designated and agreed upon

Equipment expert, but not necessarily the guru

Able to interface with team and management

Able to see big picture. Do NOT get pulled intoweeds of troubleshooting effort

Knowledgeable of entire system interactions Organized and firm

Able to multi-task


8/23

8


Organizing Your Team

Team may have all or some of the following:

Expert on the equipment that has failed

Equipment operator

May be the one operating the gear when it failed

Parts procurement

Data entry / extraction / computer guy

LO/TO guy

Runner (gopher)


7-Step Process

General Comments

Write down everything. Do not depend onyour memory.

Get initial data immediately.


9/23

9


In Parallel:

While waiting for initial steps to becompleted, what can be done?

Gather maintenance history

Get technical manual

Obtain test equipment

Immediately get observed symptoms from theoperators


7-Step Process

1. Symptom Recognition

2. Symptom Elaboration

3. List of Possible Faulty Functions

4. Localize the Faulty Function

5. Localize the Faulty Circuit / Component

6. Failure Analysis7. Retest Requirements


10/23

10


1. Symptom Recognition


Immediate Action

Immediate discovery of the problem byoperator and supervisor

Who knows?

Who should know?

Who must be informed?

Is equipment in a safe condition?

Procedure to record problem at operator level

Is there a policy in place?


11/23

11


Troubleshooting Team Arrives

This is much easier than you think

Only list what actually caused the operator torecognize that there was a fault

Do not include:

Operating conditions

Other indications

What are goals? Repair?

Restore operation?


2. Symptom Elaboration


12/23

12


Operating conditions at the time Start-up, shut-down, etc

Power level, fluid levels

Special operations in progress

Recent maintenance

Anything different than normal

Exact sequence of switch operation

Other symptoms noted: Alarms

Warnings Blown fuses

Smells

Sounds

Include

anything you

think might be

pertinent.

Symptom Elaboration


Man in charge Be ready to give options. Can we operate in reduced status?

Lower throughput, less reliable, more likely to breaksomething else, etc.

Can we by-pass the failed module (permission?)

How long to implement each option?

Risks for each option?

How long can we operate with each option? What additional safeguards should be put in

place?

Symptom Elaboration


13/23

13


Symptom Elaboration

Dont operate anything yet

What permissions do you need to continue?

This step in the process is where manytroubleshooting plans break down.

Not all indications are listed

Operator impressions / observations are not

immediatelyobtained Nothing is written down


3. Possible Faulty Functions


14/23

14


List all major functional blocks that couldcause the problem:

Power supply

Sensor

Amplifier

Etc

We are not yet looking for the one specificfailed component

Possible Faulty Functions

Dont

eliminate

anything

unless you

can prove it!


This is where Equifactor can be used

Quickly look through Symptoms for problemsavailable in the tables

Gives you ideas what possible causes you shouldlook for

This is quick method of verifying what you thinkcould be the cause

Makes you think of problems outside yourexperience



15/23

15


You may want to have a TroubleshootingGuide assembled for most frequent or criticalfailures

Allows you to quickly get to this point

Could be pulled directly from Equifactor, or evenmaintained in an Equifactor Custom Table

Often in quick, flowchart format



4. Localize Faulty Function


16/23

16


Localize Faulty Function

Actual troubleshooting

Permissions obtained

Write down expected before you take areading

Prevents seeing what you expect

Youll talk yourself into whatever you observe

Write down EVERYTHING you do May need to turn over

Will want to look at it tomorrow



Man in charge Be ready to give furtheroptions.

More options may be available, now that youknow what major component has failed.

Replace major function without knowing what exactcomponent failed?

What is risk of damaging new part without full failure

mode known?


17/23

17



Equifactor Tables may have

ideas on how this type of fault

was troubleshot last time


Linear

Test at each element

Left to right

Check input, output, power applied for eachelement

Functional Troubleshooting Methodologies

INPUT

Signal

Output

Signal


18/23

18


Half-split

Test each element

Start in the middle Check input, output, power applied for each

element


INPUT

Signal

Output

Signal

Check

Bad

Check

Good


Easter Egg

Used because:

Not trained in any particular method

No plan in place, therefore, just get going Not sure what has already been done


INPUT

Signal

Output

Signal

MostMost

Popular?Popular?


19/23

19


5. Localize Faulty Circuit / Component


Localize Faulty Circuit / Component

This is troubleshooting to component level

Troubleshoot down to lowest possible(expected) level

May require specialized test gear

Again, record everything you do


20/23

20


6. Failure Analysis


Failure Analysis

Prove to the team that the failure you foundwould cause ALL the symptoms you found.This prevents:

Replacing wrong component

Having multiple undiscovered faults

Talking yourself into your favorite failure

This is rarely done well


21/23

21


7. Retest Requirements


Retest Requirements

What retests will be required to prove thegear works?

Prove the new component is good

Prove there are no other associated faults

Prove you did not cause other damage during thetroubleshooting or repair

May be required to officially recertify thesystem


22/23

22


Correct retests are required to ensure reactorsafety.

Contained in a variety of manuals.

Maintenance & Replacement Instructions.

Equipment Technical Manuals.

Equifactor may provide guidance when a specificretest was used in the past

Can be researched and pre-approved. Agreement on the correct retest requirements is a

combined effort.

Retest Requirements


Plant Relationships

CAUTION:

Actions taken during troubleshooting efforts canaffect various plant capabilities.


23/23


Date: _________

TROUBLESHOOTING RECORD

1. Symptom Recognition _______________________________________________

_______________________________________________

_______________________________________________________________________________________ ______________________________________________________

2. Symptom Elaboration :

______________________________________________________________________________________________

______________________________________________________________________________ ________________

______________________________________________________________________________________________________________________

___________________________________________________________

3. Possible Faulty Functions :

_________________ _ ____________________________________ _ ___________________

_________________ _ _____________________________________ ___________________

_________________ _ ___________________

List operational options:Options

Lower reli ability?

By-passinterlock?

How long to implement?

Permission required?

List risks

AdditionalSafeguards

4. Localize Faulty Function :

Test Point Expected Actual Sat/Unsat

______________________________________ __________________________

_________ ____________ ___________________________________________

Troubleshooters -

! Maint. History! Plant Operating Manual

! TechnicalManual! Repair Parts

! Retests! Area se t-up

! Test Equipment


5. Localize Faulty Circuit :

Test Point Expected Actual Sat/Unsat

___________________________ _____________________________________

________________________________________________________________

________________________________________________________________

________________________________________________________________

___________________ ________ _________________ ____________________

6. Failure Analysis :

________________________________________________________________

________________________________________________________________

________________________________________________________________

___ _____________________________________________________________

_________________ _________________________ ______________________

__________________________________________ _____ _________________

___________________________________________________________ _____

_______________________________________________ __________ _______

7. Retest Requirements :________________________________________________________________

________________________________________________________________

______________________________________ __________________________

________________________________________________________________

_______________________________________ _________________________

________________________________ ______________________________ __

________________ _____ ________________ ___________________________

_____________________ _____ ______________________________________

___________________________________________________________ _____

__________________________ __________ ____________________________

repair lcd

Documents

Transcript of repair lcd