Crt television repair course- ebook by humphrey

 

    CRT TV Repair Course by Humphrey-Preview - Download as PDF File .pdf), Text File .txt) or read online. Who Want To Learn How To Repair CRT TV The Easy Way. Notify You When New Crt Tv Repair Ebook By Humphrey Kimathi Files Will Be. Recommended CRT TV Repair Ebook by Humphrey Kimathi. CRT Television repair course is an E book covering all the major building blocks in CRT Television.

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    Crt Television Repair Course- Ebook By Humphrey

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    CRT TV repair course by Humphrey-Preview, Page 1 By Humphrey Kimathi The reader of this book is expressly warned to consider and adopt all safety precaution that might be indicated by the activities Herein and to avoid all potential hazards. The author particularly disclaims any liability, loss or risk taken by individuals who directly or indirectly act on the information Contained herein. The author believes that the information presented here is sound, but readers cannot hold him responsible For either the actions they take or the result of those actions. All Rights Reserved No part of this book may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording or by any information storage and retrieval system, without permission in writing from the owner. Preface CRT Television repair course Edition is an E book covering all the major building blocks in CRT television with emphasis given to real life scenario from the technician work bench and therefore provide a good source of reference for practicing technicians. The book is divided into two parts: Part one: is composed of 18 chapters of the major circuit blocks in CRT TV and explains basic functions and common problems associated with these blocks. Part Two: is composed of 10 chapters of pure real life repair histories from the technician work bench. The book is illustrated with numerous color photos to make the reader learn faster and get the concept pretty fast. S Chapter 3:Understanding S. S sub units Chapter 4: Solving power supply problems smps using control ic. Chapter 5:Solving power supply problem for Television using transistor instead of control ic. Chapter 6: Understanding the Secondary power supplies Chapter 7: Main power fuse keep on blowing Chapter 8: Do it yourself series lamp current limiter Chapter 9: Using the series bulb for find shorted component on the primary supply Chapter Understanding the Horizontal circuits Chapter understanding fly back transformer Chapter H. Chapter 28 : Conclusion CRT TV repair course by Humphrey-Preview, Page 4 Chapter 1:Introduction to Television Repair Career This course is intended for people who are already in the field of Television repair and have basic knowledge in electronics and therefore understand safety precaution when working on electronics devices. If you are already in the field of repairs you would agree with me that most of the electronics books and colleges teach about the theory of operation and how components works. The moment you step out of that class and join the field is when you realize that things are getting tough, the customer is not interested with your papers but.

    T you find alas it is shorted again. This problem of H. T getting shorted immediately or after some times of replacement has given many technician sleep less night trying to figure out what is happening here!!

    In the lesson I am going to give you some tips on what to do to prevent the H. T getting shorted after replacement. Usually color problems are easy to solve if you do some preparation to analyze failure on this circuit And the best way to analyze this faults is to do voltage testing on the critical test point of this circuit and by so doing you will narrow down to the actual fault section pretty fast.

    But first you need to have a rough estimate of the actual voltages expected on those test points in order to analyze the information correctly. Below I have reproduced a chart of estimated voltages at those points but may vary from set to set but not too far from the figures below.

    Now that there is something on the screen it means the HV is present and therefore the fly back is okay and the heater circuit is okay and therefore not considered for troubleshooting. First check for dry joints around this circuit by tapping this small board with the back of your screw driver and see if the color changes every time you tap this circuit softly.

    You can invest on a mirror medium size and be watching the screen from the mirror when you are working behind the television and you want to see the screen without straining yourself.

    If the color keep on changing or you see some splashes on the screen expect dry joints around this board and therefore you should re solder it thoroughly. Vertical circuit problems can be manifested in many ways and therefore one has to be keen when getting clues associated with the vertical circuit because some of them do not point directly to the vertical circuit has a problem but if one is keen you can always tell if its the vertical problem causing the symptoms or not From my experience whenever you see the television screen height is narrow does not occupy the whole area from the top to the bottom of the screen Then suspect some problem on the vertical circuit, others may have some write line at the top or bottom part of the screen.

    Also black stripe above and below the screen is common, symptoms like lines on top of the screen or no image at the bottom points to a faulty Capacitor around the vertical ic. Please note that I mean the picture is present and very clear but there is no sound from the speaker. If it is no audio and no picture this is a different case and should be handed on another topic Below you can see an audio circuit of a television using ic LA Set your meter to low ohm and test between the two pins of the speaker.

    If okay it should have low reading between 4 ohms and 16 ohms. Usually for the tuner to function it will require the Vcc-in the above model is 9 volts and if this voltage is missing then the tuner will not work and hence no picture and no audio.

    CRT TV repair course by Humphrey-Preview, Page 21 Chapter Understanding and troubleshooting the micro processor Just like computers television set have micro processor which control the functions of the Television.

    Microprocessor are quite reliable and highly protected from static discharge and power surges. Most of the time if you suspect the problem is as a result of bad micro you should first be sure that the following is okay because if any of the following is missing then the micro will not work. CRT TV repair course by Humphrey-Preview, Page 22 Chapter Understanding and troubleshooting the remote control The remote control circuit in television works like the transmitter and receiver in radio circuit.

    Inside the remote control there is a circuit which emit pulses signal and in the TV circuit board we have another circuit which receiver signal and these pulses are send to the microprocessor for interpretations and action. To isolate the problem you need to confirm if the television front buttons are working and the remote is not working. If the front buttons are working then only can we suspect the remote control unit. So I went down to his residence to check on itremember most of my repairs are done on the site and therefore I normally do some preparation for the task ahead of the time.

    In this assignment I had prepared myself with the basic equipment plus a circuit diagram of the LG television any because mostly TV circuit diagram for a particular model are very similar in terms of major circuit modules. In this case from the symptoms given by the owner via the phone I was very sure the problem was likely to be on the CRT circuit board, so I went down to his place and found he was not around but the houseboy was around to assists me with what I wanted.

    Asking him about the television he told me that there was another technician there and I wanted to know how far he went into the television even before I opened it and he confided with me the technician came and after a keen observation on the screen for about ten minutes without his eyes blinking he told them that the problem is new in the world and therefore he sees no hope on the television and therefore the best place for it is in the dustbin or make it a toy for his children.

    My friend that is why it is very important always to get a second opinion even in the medical world. For me I was very happy with this technician because he was honest with himself and never attempted to repair it because he could have done even more mess. Also the osd i. This I did and confirmed there were many dry joint because the screen kept on changing. Sometimes I even managed to get a picture, which was reddish purple in color. I mean this Television has all sort of weird symptoms.

    The Television was using I. You know sometimes if you fail to get the circuit diagram of the exact model you are working on you can go round this problem by getting only the data sheet of the suspect I. C and this can go a long way in assisting you to know which pin is which for proper diagnosis. Very important is the supply v cc pin which is very important because a new working I. C from the factory is as good as a bad one if the V CC supply is missing, its like trying to drive a new car without gasoline.

    That is why it is very important to make sure the supply voltage to any I. C is present and is correct value. So from the data sheet I was able to see that for this particular I.

    C LA it is feed by three Voltage sources. Pin 1 is feed with 12 Volt DC; pin 8 and 13 is feed with 24 volts each, Please note that the 12 volts is from the secondary of the power supply and the 24 Volts is from the secondary of the fly back transformer and therefore one can fail and the other remain but still the vertical I. C will not work. I mean if any of the three supplies is missing the vertical I. C will not work and therefore if you find any of the supply missing be sure to do the voltage testing from that pin backward and find out what is blocking the voltage.

    Look for open fusible resistor or filter capacitor for that line has developed high ESR. Usually if capacitor has high ESR causes the supply for that line to drop. One thing I was sure about is that there was a problem with the vertical circuit.

    I measured all the components around the vertical I. C and they seem okay according to my meter. The voltages were also okay to me. And was just returned to the box and brought to technician B who in this case happens to be you.

    schematic 4 you: Repairing Guides

    No color symptoms you have figured it is not a big deal and therefore you will hold it a bit to attend more serious repairs So you apply power with your eyes fixed on the screen to confirm what the customer told you two days ago.

    Checking on the power outlet it working well and therefore you decide to open the set to see if the fuse is gone and when you finally open the television you notice the fuse is okay but a lot of the circuit has been tampered with and components even missing including the microprocessor, you know how much it cost in your local currency.

    Just when you have confirmed the above here comes the customer coming to see the progress of the set and as you begin to thank him for coming your way so that you can show him how his set was abused by the previous repairers he tells you that he only knows you and if you are not able to fix his set just bring it back the way it was with NO COLOR SYMPTOMS. Or he calls the police. These things happen and if they have not happened to you yet please take my advice otherwise history does repeat itself.

    So I applied the rule above and I switched on the Gold star television and I observed the following The set came up beautifully and I noticed the picture was partially closed with a black slip below and on top of the screen. Sound was okay. As a technician you can make a lot of conclusion just by watching the screen if you have a good knowledge on how that equipment circuit works.

    CRT TV repair course by Humphrey-Preview, Page 26 Chapter Samsung Television dead I received a phone call from a customer who wanted me to go and check his television which has developed a problem and was not working. So I walked to his residence for that mission with a few tools: a multi meter which in electronics world is actually the eyes of the technician, I mean you cant see electricity voltage with your own eyes but the meter can see and tell you if there is voltage or not and a screwdriver to open up the set.

    The set was brought to me and I asked a brief history of the set especially the last moment before it died, I was told there was some smoke seen coming out of the set before they switched of quickly. I didnt intend to confirm that by powering it on again and therefore I opened the set and started scanning around the power supply looking for a component with catastrophic failure because I figured that since there was smoke, there must have some fire also and where there is fire there must be a heat mark or component swollen or broken to pieces.

    Next I decided to check the state of the fuse and it passed the meter test with flying colors, so I decided to apply power and do some voltage testing. I applied power and to my surprise nothing happened, no smoke so I concluded that whoever said that he switched off after seeing the smoke did it a little too late. So I started my voltage testing, with my meter negative probe on the main capacitor negative pin, I started to test the voltage at the actual main capacitor and there were zero Volts Nothing!

    I opened the set and scanned around the primary side of the power supply and found the main filter capacitor was bulging out. I replaced it together with the control chip str-G which almost always goes when there is power surge. After replacing the two components the set came up but no color Picture was black and while with some very thin lines across the screen.

    I hit the set softly with my bare hands and the color came on but intermittent. Also white lines across the upper part of the screen. There is also blank part above and below the screen. In my opinion a technician and a medical doctor have a lot in common, we deal with symptoms facts analyze them and figure out from the data at hand the most likely cause of those symptoms.

    Fortunately for doctors they have added advantage because at least with human being they can speak out how they are feeling, add some additional test and there you go, Drug prescription is done. Now for technicians machines dont speak, therefore we rely heavily on keen observations, testing critical test point, some history from the owner on how the problem started etc to be able to figure out the actual circuit causing the problem symptoms at hand.

    This part is very critical, the more information you gather the more likely you are going to narrow down to the actual circuit which is causing the problem. If the machine Television or Monitor has something on the screen, you can get a lot of clues on the screen behavior even before opening the machine. Let take this GLD TV as a case study, the information on the headline of the article is what I was able to observe on the screen. I have tried to reproduce the symptoms on the picture below 1.

    Screen height is narrow. Clear picture below the line but distorted picture above the line. Also lines across the upper part of the screen. These are 5 strong facts all pointing to Vertical Circuit, am I right? I put my finger on them and they were also getting hot. This was enough evidence that these two capacitors are faulty. I opened the set and I measured the voltage across the main capacitor. No voltage was found-absolutely zero volts.

    Alas what is the problem now? All over a sudden I heard a loud crack sound and noticed a resistor has broken downsee resistor R above across the degaussing coil- what was it doing there in the first place anyway in most set its written optional but in this case it was there I never had a chance to know its actual value to date. It was also very hot and broke into pieces. Remember a fuse can tell you a lot about the last moment of any equipment before it died in medical terms postmortem 1.

    Fuse blown, dark inside - Means the machine died due to heavy shot. Please be sure to use the light serious Lamp to bring up the machine after replacing the fuse. Solving power supply problem for Television using transistor instead of control ic.

    Chapter 6: Understanding the Secondary power supplies. Chapter 8: Do it yourself series lamp current limiter Chapter 9: Using the series bulb for find shorted component on the primary supply Chapter Understanding the Horizontal circuits Chapter T getting shorted after replacement Chapter Understanding and troubleshooting Colour problems Chapter Understanding and troubleshooting Vertical circuit Chapter Understanding and troubleshooting the Audio circuit Chapter Understanding and troubleshooting the Tuner circuit Chapter Understanding and troubleshooting the micro processor Chapter Understanding and troubleshooting the remote control Chapter Gold star TV vertical partially closed Chapter Samsung Television dead Chapter Sony TV GE..

    Chapter Chapter 1: Introduction to Television Repair Career This course is intended for people who are already in the field of Television repair and have basic knowledge in electronics and therefore understand safety precaution when working on electronics devices. If you are already in the field of repairs you would agree with me that most of the electronics books and colleges teach about the theory of operation and how components works. The moment you step out of that class and join the field is when you realize that things are getting tough, the customer is not interested with your papers but.

    So the only way to make your customers believe you are up to the challenge is by quick diagnosing of the problem and repairPeriod! This book is written to address the above issues comprehensively as most of the materials in this course will be practical real life experiences from the technician workbench.

    Tools of trade Every trade have his own tools of trade, for Television repairs the minimum you should have include: Chapter 2: S Most of the electronics equipment nowadays use switch mode power supply smps to generate various voltages to feed other circuit.

    Power supply section of all electronics equipment is one area where there is a lot of stress for the equipment as far as components are concerned due to high currents and voltage involved and therefore most of the electronics problems will be power supply related and also the horizontal circuit which we will study latter in this course For now let us concentrate on the switch mode power supply components and what they do and the effect they have on the supply when they fail.

    When you switch on the Television via power switch, the power passes through a fuse which is used for safety purposes, so whenever you see a fuse has failed don't blame it because that why it there to do-that is to blow if there is a problem with the power supply like a shot, the fuse will cut off the power to the equipment to avoid further damage to the equipment.

    And also preventing the equipment from catching fire! So next time you see a fuse has blown you need to appreciate it for job well done, on the same note I believe you have understood why you should never replace a fuse with a Jumper wire- always think safety first to you and also to your customers. Fuse often fail by being open and you can easily confirm that with a meter set to low ohm resistance.

    Varistor Another components found in the smps in some of the good design is the Varistor, see picture below. Varistor This is also a safety component and is always connected on across the AC power line, but they do not conduct unless the AC voltages increases above normal like during power surge caused by Lightening or using outlet which is not well regulated like using generators.

    So if there a power surge the varistor will conduct and because it is connected across the AC power line it will create a short circuit across the power line and hence force the fuse to blow and hence disconnect the equipment from further damages. Chapter 4: Most problems with equipment using smps like television and monitors are power related. This is because powers supplies run under considerable stress due to high voltages and currents involved around these circuits.

    In order to understand how to solve smps problem I am going to show you how to analyze common failure mode. First confirm the television cable is not broken inside, you can check this by measuring the voltage across the AC power input connector on the circuit board. If the voltage is reaching the circuit board, then look for the fuse and see if it is blown, if the fuse is okay check also the surge limiter is open or not. If these two components are ok then most likely there is no short on the primary side of the power supply note: Short in the primary side of the power supply usually cause the surge limiter or the fuse to blow.

    From now on we shall be using the main capacitor negative as the Ground for all the measurement of Voltages on the primary side of the power supply.

    I have modified my meter ground probe with a crocodile clip so that I can attach it to ground point of the equipment I am repairing and therefore I use only one hand to probe the circuit.

    This is a safety precaution because as you know for there to have a potential difference there must be a connection between the live and the ground. So if you are using your two hands and incidentally touch the live and the ground then current will flow through your body and this can be fatal. But if you are using one hand it is not possible.

    These types of the television are also very common in the market and therefore I would like to highlight how to go about them when troubleshooting their power supply. These television are mostly imported from china and if you have been working on them you will notice that they all have the same circuit diagram but different faces and Names and therefore in this lesson I am going to use an Akira Television as our case study.

    On the above picture you can see the main component that you would find on the primary power supply when you open up the Television. Please take some time to locate these component on the actual board if you have one near you. The First thing you should do when a customer bring in this type of television as usual is to confirm what the complain wasI mean if he or she said no power or no audio please confirm the same before even opening the set.

    Then open the set and scan around the primary power component both the top and underside and see if there is catastrophic failure on any component e. If any of them is broken dont replace it first before you check the state of the Chopper transistor in our case D Understanding the Secondary power supplies If the switch mode power supply s. Usually the number of output from the secondary side of the chopper transformer varies from model to model.

    To start with let analyze the secondary supply of the Akira TV made in china. Please note that by analyzing. Below you can see the diagram of the Akira television made in china and if you look at the circuit below you notice that it has several secondary output and we will analyze them one by one.

    Before you analyze them first let me point out that all measurement on the secondary side of the power supply. Also to check the output voltage from the chopper transformer you have to measure Voltage at the cathode Of the secondary diode. Chapter 7: Main power fuse keep on blowing When you receive a television in your repair shop, it is usually very important to check the health of the power supply.

    You can quickly check for obvious safety components to see if they have been triggered on due to fault elsewhere or not. The main safety components in the television power supply is the fuse and the surge limiter I mean triggered by fault elsewhere because rarely does a fuse or surge limiter blows alone, there must a cause why it has blown. Whenever you find any of these component is open and you replace it most of the time you will find that the same component open again.

    This is because there is a fault short somewhere else and what the fuse is doing is a safety measure to cut of the supply otherwise fire can even break out from the equipment. So the rule of the thumb is that whenever you find a fuse or surge limiter is gone never replace it until you have checked the condition of the switching transistor or control ic in that power supply.

    To check the switching transistor set analogue meter to X1 and measure between leg marked C and E 1 with the red probe on the middle leg C and black probe on leg marked E. Do it yourself series lamp current limiter In this lesson we are going to learn how to make yourself a series bulb current limiter Materials required 1 Bulb holder 2 Socket with switch 3 Main Plug 4 Power Cable 5 Piece plywood 6 screws 7 Surface box 8 Bulbs.

    Chapter 9: Using the series bulb for find shorted component on the primary supply In chapter seven we discussed some of the causes that can cause the fuse or the surge limiter to blow In this lesson we are going to learn how you can use the series bulb to find hard to find short in the primary power supply.. I mean primary because short on the secondary side rarely causes the fuse to blow but only causes the power supply to appear dead. Sometimes component can develop semi short and very hard to test them with a meter like one time I came across a transistor which was shorted base-emitter junction which was around 82 ohms and as you know most meter recognize a short if it reads less than 30 ohms.

    This is the supply which supply the fly back transformer to get other voltage which are generated by the fly back transformer just like the voltage which we saw in our previous lesson being generated by the switch mode power supply.

    Horizontal circuit can be divided into two sections. From the diagram above the circuit on your left of the blue vertical line is the horizontal drive circuit Basically this circuit is composed of five important component which includes. RC- network-used to protect the drive transistor from induces voltages from the drive transformer 2.

    Current resistor-Set the current and voltage to the driver stage 3. Filter Capacitor-Filter and boost the current to the driver stage by charging and discharging through the drive transformer primary. Drive transformer-this is basically used for impedance matching between the horizontal drive circuit and horizontal output circuit. The screen voltage behaves as brightness control and therefore whenever you find the screen is dark especially after replacing the fly back and the screen is still dark even after using the remote brightness control button then consider adjusting this knob little and see if the brightness increases.

    The focus knob is used to focus the picture and therefore if you find again after replacing the fly back the picture is dis focused then you also try to adjust the focus knob a little. If you adjust the focus and still not change to the picture then perhaps the CRT is faulty or the fly back itself is bad, but before you change these first change the CRT neck socket and see if the focus improves.

    Also in some model the RGB amplifiers supply comes from the fly back transformer usually around Vdc This Voltage if it is missing or low usually causes the screen to be very bright and with lines across the screen but when this voltage is high causes the screen to appear dark blank.

    T getting shorted after replacement This is a common phenomena with HOT whereby a customer bring in a Television and after checking it find out the Horizontal output transistor H.

    Crt tv repair course

    T is shorted. Naturally you replace the shorted transistor with a new one and you power on the Television and it come up beautifully and before you begin to celebrate the television goes down again stop working You open the set and after checking the health of the same component H.

    T you find alas it is shorted again. This problem of H. T getting shorted immediately or after some times of replacement has given many technician sleep less night trying to figure out what is happening here!! In the lesson I am going to give you some tips on what to do to prevent the H. T getting shorted after replacement. Understanding and troubleshooting Color problems When you receive a television in your shop with color problems but audio is OK the best place to start your.

    Usually color problems are easy to solve if you do some preparation to analyze failure on this circuit And the best way to analyze this faults is to do voltage testing on the critical test point of this circuit and by so doing you will narrow down to the actual fault section pretty fast. But first you need to have a rough estimate of the actual voltages expected on those test points in order to analyze the information correctly.

    Below I have reproduced a chart of estimated voltages at those points but may vary from set to set but not. Now that there is something on the screen it means the HV is present and therefore the fly back is okay and the heater circuit is okay and therefore not considered for troubleshooting.

    First check for dry joints around this circuit by tapping this small board with the back of your screw driver and see if the color changes every time you tap this circuit softly. You can invest on a mirror medium size and be watching the screen from the mirror when you are working. If the color keep on changing or you see some splashes on the screen expect dry joints around this board and therefore you should re solder it thoroughly. Understanding and troubleshooting Vertical circuit Another block where there is potential of problems in CRT television and monitor is the vertical circuit.

    Vertical circuit problems can be manifested in many ways and therefore one has to be keen when getting clues associated with the vertical circuit because some of them do not point directly to the vertical circuit has a problem but if one is keen you can always tell if its the vertical problem causing the symptoms or not From my experience whenever you see the television screen height is narrow does not occupy the whole area from the top to the bottom of the screen.

    Then suspect some problem on the vertical circuit, others may have some write line at the top or bottom part of the screen. Also black stripe above and below the screen is common, symptoms like lines on top of the screen or no image at the bottom points to a faulty Capacitor around the vertical ic.

    Please note that I mean the picture is present and very clear but there is no sound from the speaker. If it is no audio and no picture this is a different case and should be handed on another topic Below you can see an audio circuit of a television using ic LA Set your meter to low ohm and test between the two pins of the speaker. If okay it should have low reading between 4 ohms and 16 ohms. Usually for the tuner to function it will require the Vcc-in the above model is 9 volts and if this voltage is missing then the tuner will not work and hence no picture and no audio.

    Understanding and troubleshooting the micro processor Just like computers television set have micro processor which control the functions of the Television. Microprocessor are quite reliable and highly protected from static discharge and power surges. Most of the time if you suspect the problem is as a result of bad micro you should first be sure that the following is okay because if any of the following is missing then the micro will not work.

    Understanding and troubleshooting the remote control The remote control circuit in television works like the transmitter and receiver in radio circuit. Inside the remote control there is a circuit which emit pulses signal and in the TV circuit board we have another circuit which receiver signal and these pulses are send to the microprocessor for interpretations and action. To isolate the problem you need to confirm if the television front buttons are working and the remote is not working.

    If the front buttons are working then only can we suspect the remote control unit. So I went down to his residence to check on itremember most of my repairs are done on the site and therefore I normally do some preparation for the task ahead of the time.

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    In this assignment I had prepared myself with the basic equipment plus a circuit diagram of the LG television any because mostly TV circuit diagram for a particular model are very similar in terms of major circuit modules. In this case from the symptoms given by the owner via the phone I was very sure the problem was likely to be on the CRT circuit board, so I went down to his place and found he was not around but the houseboy was around to assists me with what I wanted.

    Asking him about the television he told me that there was another technician there and I wanted to know how far he went into the television even before I opened it and he confided with me the technician came and after a keen observation on the screen for about ten minutes without his eyes blinking he told them that the problem is new in the world and therefore he sees no hope on the television and therefore the best place for it is in the dustbin or make it a toy for his children.

    My friend that is why it is very important always to get a second opinion even in the medical world. For me I was very happy with this technician because he was honest with himself and never attempted to repair it because he could have done even more mess. So I opened the set and went straight to the small. Also the osd i. This I did and confirmed there were many dry joint because the screen kept on changing. Sometimes I even managed to get a picture, which was reddish purple in color.

    I mean this Television has all sort of weird symptoms. The Television was using I. You know sometimes if you fail to get the circuit diagram of the exact model you are working on you can go round this problem by getting only the data sheet of the suspect I. C and this can go a long way in assisting you to know which pin is which for proper diagnosis.

    CRT TV Repair Course by Humphrey-Preview

    Very important is the supply v cc pin which is very important because a new working I. C from the factory is as good as a bad one if the V CC supply is missing, its like trying to drive a new car without gasoline. That is why it is very important to make sure the supply voltage to any I.

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    C is present and is correct value. So from the data sheet I was able to see that for this particular I. C LA it is feed by three Voltage sources.

    Pin 1 is feed with 12 Volt DC; pin 8 and 13 is feed with 24 volts each, Please note that the 12 volts is from the secondary of the power supply and the 24 Volts is from the secondary of the fly back transformer and therefore one can fail and the other remain but still the vertical I.

    C will not work. I mean if any of the three supplies is missing the vertical I. C will not work and therefore if you find any of the supply missing be sure to do the voltage testing from that pin backward and find out what is blocking the voltage. Look for open fusible resistor or filter capacitor for that line has developed high ESR.

    Usually if capacitor has high ESR causes the supply for that line to drop. One thing I was sure about is that there was a problem with the vertical circuit.