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Electronic Repair Questions/Answers and Testimonials Part 14

By on September 21, 2008

DEAR SIR,

I HAVE A PROBLEM WITH TFT LCD. FOR 5 MINUTES IT WORKS PROPERLY AFTER THAT IT’S SCREEN CHANGES TO WHITE. SIR PLEASE GIVE ME SOLUTION HOW REPAIR THIS MONITOR. THANKING U SIR. YOURS FAITHFULY

J.S

Hi J.S,
Check all e-caps and for dry joints. If all tested good then suspect a bad lcd panel!

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greetings my friend, how things going. hope all is wel with you. i have a question concerning the esr blue meter. what is the highest capacitor the meter can read? the meter that I have reads up to 2.2k. my meter is

EMS, I think that is the name of the company. let me know please.Hi W,
I’m fine and this link will show you the highest capacitor it can test:
http://members.ozemail.com.au/~bobpar/2003esrchart.txtJestine

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Is there any way to find the Heated Capacitor Value? Sometimes I came across heated capacitor whereby the value printed on the outer plastic skin shrink due to the heat from the capacitor or explode capacitor (usually the Filter Capacitor), thus result to the printed value on the plastic skin can’t be read properly.

Hi R,

If it located at the secondary side then i will use a 1000uf 50vdc as replacement. If it locates in other circuit I will compare the set with similar model and refer to schematic diagram. Sometimes I will simply put in a value and retest the set again but of course with a higher voltage value.

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Thank you very much for this Newsletter. It reveals to me so many useful possibilities that I ignored. It increases my ability to use my measuring equipment to solve my problems. THANK YOU ! You are welcome!Can I achieve the same results with the “SMART TWEEZERS” that I just bought three weeks ago?No, Smart Tweezer have it own advantages over ESR meter.

I have bought it because it measures: C, L, R, ESR, Rs, Rp and DC up 8V.I just have start small workshop and passed month I bought:An Insulator transformer,A two channels Scope,A digital Multimeter,(with transistor tester feature)An Analog Multimeter,A complete “PACE Desolder”All above equipment are second hand’sBut the Smart Tweezer is new one. Congrat on you small workshop-hope you are getting more business!Few days ago, I have made my 24 Volt Lamp for testing 12 V Power Supply. Its great to hear that!Jestine, do you know what is one of my major problem? It is nice and exciting to measure, search and finally find the defect components and then it begins. Where to get this special component from? Here in The Netherlands is not so easy for a small beginner.Try search from https://www.jestineyong.com/?cat=12

It is one the point that you have mentioned in your Newsletter of August to join other Members who are RepairersI hope to be Member soon.

You can find from internet any repair group. from there you can join them.

Jestine, thank you once more.

No problem!

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Thanks a lot for your free report, it was useful for me. i have learned on how to trouble shoot power, power regulation and smps problems. Thank you very much God bless.
Kind regards

japeth mutua
mombasa

KENYA====================================================Hi Jestine, I have notice that there are a lot of computer LCD monitors that developed this problem, WHITE SCREEN with a LOT OF VERTICAL LINES ACROSS. Is this a common problem after years of using the lcd monitor ( graphics board ) or the LCD screen itself?

Regards,

Arvin,


Hi Arvin,
Usually it was caused by bad e-caps. If all the e-caps tested okay then the fault is in the lcd panel. It depends on brands and sometimes a loose connection cable between the mainboard and the lcd controller board may cause this problem too.

Jestine

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Hi JestineI’m working in electronic repair field but not an experts. I’m very satisfied with your LCD monitor repair & Testing Electronics Components. It’s great and very helpful.

Korea

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Hello mr. justine Yong i found your site useful to me, I am from Uganda – Africa Nice to know you

but i want to improve my carrier since iam upcoming technician.dear mr how can you help me to improve my carrier beacuase ihave a workshop which repaires tvs, radios ,computer and as technology developes itried some lcd+flat screens but its not easy to know the ploblem since.

Read more from my repair articles and also you need to diligently buy more books to read, visit related forum and don’t give up.Most technicians in our country use AVD830D digital meter and other analogue which at time give improper values , which meter do you advise me to use when am in that business?. Any Digital meters will do but don’t get the Cheap one. You can use Fluke digital metersi also doing pc repaire, so what is the simplest way to follow so that you can help me or offer me your services since am so interested in that business?.Sorry i can’t help you on this because i don’t do pc repair anymore. Try visit this link :

http://www.elstonsystems.com/prod/pc_post_diagnostic_card.html

thanks for every thing you do for us but want to know the price of those meters which are good for electronics and where they are found http://www.electronicrepairguide.com/blue-esr-meter.html and

http://www.electronicrepairguide.com/blue-ring-tester.html
mr Yong i don’t know whether you’re good other electronic devices lic\ke CRT tvs ,Amplifiers and many other because i liked youre reaserch work and please try to keep us imformed I’m only in the CRT/LCD Monitor repair and power supply repairBest Regards,
Jestine
http://www.JestineYong.com

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Hi Jestine, Thanks for the shipment. I already got the Meter but I found out there have got 1 parts difference. The parts which i mention above is 3-terminal regulator low-dropout IC. By right, I should get LP2950cz-5.0 IC. But unfortunately What i get is 78mcyfe ky5050 IC and also i not able to check the datasheet due to weird description printed on the body of this parts.Could you advice me about this parts? Is it 5 V voltage regulator IC? Then once I finish assembly all the parts to the PC Board, I facing “No Power” symptom on Initial Checking procedure. What i means here is there have got no +5V of IC2 and IC3.I felt sad of my meter. Any hint can you provided? Best Regards.DarrenHi Darren,
The voltage regulator (5v) is an upgrade version which can save battery energy even better. Try carefully checking all of the soldering and the position of the components especially the transistor. I had this meter fixed by a buyer before and it can’t work and found that he had actually installed wrongly on the transistors. Not only that, he place the wrong number too. A 2n3906 put into the 2n3904 location!

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Hello jestina, I also interested to learn electronic but i’am working now as electrician but still poor about electronic , can you recommended to me , where should I start first , In my profesion I must learn Electronic and also i still poor on English language, thank you.Hi N,
You should start reading my ebook first at http://www.testingelectroniccomponents.com . Once you are good at testing electronic components you can begin to start to repair any electronic equipment.

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Purchased your LCD ebook last Aug 27, 2008.

I asked my good friend S.Y to do it for me since

Western Union charge is quite high. Anyway i have a good time reading your eBook and it’s very informative.Best regards,N.T

Sir Jestine,

Good day. Thank you so much for the advice. You are correct. Through your advice yesterday, the unit is now showing good picture with no traces of abnormalities.

Thank you so much. Your help is greatly appreciated. Though I also repair motherboards, video cards, hard drives, psu etc, I find LCD monitor repair interesting and as an added skill.

Best regards,

N.T

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Hi Jestine,

I finished my analysis about this white screen with heaps of vertical lines. For IBM, it was caused by the LCD itself….. I’ll check HP next……… Initially I was thinking about a software bug, maybe I was thinking too much…. I’m a big fan of yours; I will definitely buy your LCD monitor repair e-book… I’m just waiting for the currency to settle…

regards,

A.C

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Hi Jestine,
I’m very happy when i received your email respond and also when i go through all that the email from you. For me in the world of business, nobody want to do job without paid but you still continue email to me even though I’m still not buying your eBook. Actually I really want to buy your eBook but right now i am going to face a lot of problems were it come all together and now i try to solve that one by one cos of all related a big money. So i hope you can understand and give me time about it.i can feel when i buy your ebook so i can settle more problems in repairing tv and etc.So once again i like to say Thank You and will get your ebook as soon as possible.

c u on next time,thank
M

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hello, mr jestine, how are you. i like you help me about two problems. first, i have a monitor with dim screen fault, this monitor uses lm1279 video preamplifier have changed this circuit but the fault remain the same and there is a thing that i like you explain me, It could be the pc tube already weak. Check all of the voltages of the CRT board. If the voltages are within range then suspect a weak tube.

the sda line does not measure 5v but it vary between 1.5v and 3v .

It could have something shorted in this line. Try remove one by one of the IC in the Monitor and “On” again.
the second problem, i have a monitor with one vertical line. i have tested the components surrounding the deflector and it seem all good, can you help me about these problems. thanks. Make sure the output (H2) of the horizontal yoke coil have voltage. If too low or no voltage suspect either the yoke coil or corresponding components have problem. Dry joint in this area are quite common too.

jestine

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Dear Mr. Jestine,

I have this fax PSU dead on secondary side, I already checked all the secondary component and it looks okay, but I don’t know exactly how to test the TA7805S IC. The primary side is okay, and all the pin of the transformer at the primary side has voltage, but lost at the secondary side. How to solve this? Thanks in advance.

PS. I attach 2 picture to support my explanation.

Best Regards,
Julianto.

Hi Julianto,
Have voltage in primary side doesn’t mean there must have voltage at secondary side. The most important thing is that the power FET must switch. Have you replaced the power IC? What is the actual complaint? To test the 7805 IC just place your red probe to pin 1 and black probe to cold ground. It should have voltage about 7 volts to 15 volts depending on designs.

Jestine

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We have quite a few GNR TS702 LCD Monitors probably nearing a year old and
I’ve noticed that some of them develop colour problems. The display is all
green, pink or blue. Have you come across this? Hopefully yr book will be a
great help.

Best regards

Colin

Hi Colin,
The color problem could be cause by bad e-caps, loose connection cable between the main board and the lcd controller board and last it could be the lcd panel problem.

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I really want to thank for all your publications. I have gained a lot from. Keep it up.

G
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Hi Justine,

a pleasant day to you, I’m one of the many who subscribed to your e-book on LCD Monitor Repair. and I must admit that it is a big help to “unburden” most of my pending repair job on all monitors regardless of size particularly LCD’s. The bonus report is a lot of help too. Many thanks and more power to you !
Best Regards,

Ed

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Thanks for your reply, Jestine. I bought the book and have just started reading it. So far, it’s very good!

Best regards,

Pete

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4 Comments

  1. kk

    July 20, 2010 at 8:56 am

    hi Mr.jestine yong,
    Is LP2950cz.50 same to ordinary LM 7805 voltage regulator?also can I replace CMOS BSS138 with any other CMOS?if yes please suggest some

    with regards
    kk

    Likes(0)Dislikes(0)
  2. admin

    July 21, 2010 at 8:59 am

    HI KK,

    The LP2950CZ.50 has lower output current (100ma) as compare to 7805 (1 Amp. Sorry no info on the CMOS.

    Jestine

    Likes(0)Dislikes(0)
  3. Jake R. Pomperada

    September 25, 2010 at 7:11 am

    Hi Jestine,

    I am Jake R. Pomperada from the Philippines I am one of your subscribe of your news letter that I found it very useful in electronics. Thank you very much for sharing your knowledge and skills to us.

    By the way I have a question I have a CRT AOC Model No. 1770 that does not display it only give green blinks in its LED power indicator. I already replace the HOT trasistor in hoping to cure the problem but still the problem still exist any ideas why there is no display and only blinks in green. Thank you very much you can send your answer at my email address.

    Regards,

    Jake 😀

    Likes(0)Dislikes(0)
  4. admin

    September 25, 2010 at 9:44 pm

    Hi Jake,

    Try isolate the problem first using this link:

    http://www.scribd.com/doc/2957819/TT204-Identifying-television-SMPS-problems

    The blinking can be caused by either the power side or the high voltage side thus you need to separate these section.

    Jestine

    Likes(0)Dislikes(0)

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