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Electronic Repair Questions/Answers And Testimonials-Part 48

By on February 5, 2010

Hi Jestine,


Thank you for the reply I appreciate it, I bought your ebook to help teach my daughter about fault finding & have to say it is 1 of the best & easiest to read books that I have come across,

Best Regards: Andy




Hi Allers,

hi there jestine thanks for all your good e-books im still beginner on tv re-pair i bought all your e-books .


.i have a tv with no hi voltage on flyback ..all voltage after smps is ok ..i have check flyback primary with dick smith tester i have 7 lights ..i read your artical about check wave form to base of hot ..i have no scope is there another way to check .

The best is to use scope as meter would not give a good answer.

.i have check all small transister find ok all caps with esr meter ok check all resister but no volts on the high output the heater light does not light up as well i change flyback from another working tv same problem im stuff please help tv model FINESSE UTSAV FN3780 ALSO I CHANGE THE HOT AS WELL NO Luck THE B+ voltage is 110v on flyback and on middel pin of hot (horisontal transister)please help thanks

Since there is 110VDC  to the flyback then i guess it could be a missing HOT base waveform.

Have a good day!





Hello Sir Jestine, good day I have a question you, how to test this STR6656 five pins if good or bad?



HI Sio,

Power On the set and test the supply input voltage and output waveform. The best is to direct replace the power IC and retest. Before that make sure all the components are tested good first.





HI Kristjan,

What kind of meter do you recommend to buy
for testing MOSfet(what is the meter that you use
for testing in 10Kohm range)?

Sunwa or any branded meter that have the x10 k ohm range.

Only 10Kohm range is needed,
if meter goes beyond 10Kohm range,
then that meter in not suitable for testing

Don’t get the  100K ohm range because the voltage in the meter is not high enough to accurately test the Mosfet.





Hi Jestine


You are in the way to make me somebody from nobody your practical newsletters and valuable guids are taking me to the right track to be profisional electronic repairer.

I recived advanced electronics diploma and took training in private electronics workshoop but I was furstrated by what I see from most electronic repairer : try & error fault finding, which is time consuming & tedious, not progrsssing from year to year: interms of their scop of techinque, methodes of fault finding , missmanagement of their time & being stagenant in the same amount of income from year to year.


Seeing this I was doing only satellite dish installation in Ethiopia to earn my living. But after your incurraging & practical e – mails I started  repairing  boldely electronic equpements I am becoming familier with printed circuit bords & their most frequent faults, like eliminate cracks by soldering leadpoints cleaning the circuit board. I also started to open TV cover to check weather it is minor problem like fuis, switch,this is my begning ! 


You lead me to the right way to becoming profisional electronic repairer. If I spent my time purposefully towards my goal and follow your guid there is no resion that I will not be profissional eelctronicrepairer . After your e – mails I am complitly different person than befor you began making me rich. I am also encurraged to buy your E- books.


Let your e – mails dont depart from me.

Thanks Jestine. 


Henok berhanu.


From  Ethiopia




I believe I have come to the right place at the right time. I have read some of your messages on your website and I am very much eager to get going. A few questions.

1. How can I start off testing all the basic components and then start repairing? Is there a basic step by step instruction you are using?


HI Othello,

Thanks for your email. Start with this ebook first Testing Electronic Components. Once you are good in testing electronic components, in fact you can start the repair work. Next steps would be getting either the SMPS or the LCD Monitor repair ebook.
Along the way, if you have any problem in electronic repair you can always email me for support!

Have a good day!





My grandson picked up a powered subwoofer at a yard sale….it had a blown fuse.  It was labeled

2 amp….but before I could inspect it, he threw it away.

My question is:

Would a 100 watt amplifier inside the speaker use a quick blow or slow blow type of fuse? 

Glenn Normand


Hi Glenn,

Thanks for your email. If the sub woofer is using the switch mode power supply then install a slow blow fuse and if it using linear transformer then use a fast blow fuse.





HI Julien,

1- When you replace a capacitor in a power supply, is there a maximum voltage above the original capacitor’s voltage. For example, if the original capacitor is 1000uF 10V and I replace by a 1000uF 35V … is 35V too much?

The best is to use a voltage that is slightly higher like 16 volt. A higher volt would cause more and have less space for installation.

2- When you replace a MOSFET in a SMPS  or the inverter circuit by another MOSFET but different part number…what are the most important things you need to check on the datasheet to make sure the replacement part is ok? By the way, I already know that I have to check for NPN or PNP type…

For mosfet, you need to check the voltage, amp and watt and make sure the ohm value is not too high or too low.

3-Do you know how to repair the vertical lines on LCD panels considering your rubber trick thats in your book wont work in that specific case?

No, because at the moment i have not heard of anyone that can joint the contact.

Thank you very much for sharing your knowledge … and if you are stuck with a problem, don’t hesitate to ask me because maybe I can help!

Okay no problem!





Hi Paul,

If the MCU doesn’t send  any power on signal to power supply or inverters what do you normally do? (sometimes there’s not even remote diode lit on the front TV panel!!!)

First, the MCU is programmed to run if it received supply voltage and some important signals like the H/v signals. If the MCU program or the MCU itself have problem, it will not output the on signal. You can either reprogram the MCU (if you have the programmer) or replace with a MCU that already have program in it.

Do you suspect MCU to be bad or EEPROM or FLASH memory to be faulty?

From experience, it is usually the MCU.

Is it best in this case to replace whole main board or something else?

If you could get the MCU with the program and is cheaper than the mainboard then replace only the MCU.




Your Name: Martin Tan
Message: Hi,Jestine

I stumble on your site when googling for line trans for pc monitor.I have a few monitors which I like to repair.It is sheer waste to throw away such techonology.

I suspect they all have line trans.problem.Your site has given me hope in my persuit.

I want to congratulate you for your wonderful site.

Keep up the good work.




Hi, I’m also wishing you all the blesssings.

sorry if i cant reply promply, for i am bussy with my business.

i would like to ask you what’s the pros & cons of being an authorized service center.

and what brand would be the best.


thank you!





HI Nam,

It could be any brand and not easy to become authorized service center.

You need lots of staff, test equipments, good work place plus security, commitment to work during holidays and etc.

The benefit is, you will be getting lots of first hand information from the company and you will not lack of anything to repair thus you are guaranteed to have continuous repair work.





good day sir jestine! i just wanna ask you this kind of problem i encountered.. this is a sony tv model KV-2168MT. there is an indicator power signal but if we turn on it will go bach to standby mode. how can we determine what causes this kind of problem? we used a new jungle IC but still it doesn’t work. what are other options we shall do to fix this problem? please do help me. thank you.


HI Rogelio,

Is the CPU receiving the right voltage. Sometimes a bad EEPROM or CPU could cause such problem. Make sure the HOT is not shorted or leaky.




I jestine Yong wath is the best surfacemount removeal tool you can reccomend thank you


HI Dwight,
I just use normal rework station and it can do the job well.





having trouble with some psu’s in smaller lcds like the nec 1550v still learning the basics can you give me any tips i have 3 units that do not power on but the power led flashes green somewhat rapidly and then a fourth that works fine but i have compared nearly everything save a few components im not sure i can test with my multimeter.


Hi Neo,

Is the output voltages from the SMPS good an stable? If yes then suspect a bad MAINBOARD. If no then suspect either the inverter board components shorted that pulled down the SMPS or the SMPS itself has problem.





Hello Mr. Yong,
I have a BenQ FP71G + LCD monitor that has the following problem:
    -do not light the lamps backlight.
I read his guide for the repair of the LCD BenQ FP71G + and I replaced all the components you mentioned in the Guide (Pico fuse, transistor C5707, FQU11P06 FET, 1000UF 16Volts E-cap and 22 UF 250V polyester capacitors).
The lamps are lit but only x hours a couple of seconds, this may depend on what type of problem?
Please give me help, I can not go further.
Thank you and I send my sincere greetings.


HI Alipante,

If the lamp for a split of second then check on the backlight because a bad backlight could cause such problem.
Is all the voltages from the  SMPS  are good and stable?





Hi Sir..


this is my first mail. i need some help  from you.

In my PROVIEW LOW RADIATION CRT MONITOR Blue Colour patch come in center

i need solution about above prob.


plz. replay me..

thanking you ..




HI Anand,

You need a demagnetizer to remove it if the internal degausser is not strong enough. If it still there after using the external demagnetizer then i guess the crt tube have problem and need replacement.





Hi Jestine,

I have a Sumsung SyncMaster 763mb computer CRT monitor lying around for more than 2 years.

It was discovered having color display problem which could be fixed by pressing the cable near the
connector to the PC. My elder brother cut off the connector but failed in the attempt to properly resolder back
the wires to their pins accordingly, and it was left in the store since then.

I wish to give a life back to the monitor.
I wonder if you have any pin diagrams which could help me identify which wire is to which pin?
I noticed that the cable contains more than just RGB wires. There are several more other tiny wires too!!

Thanks in advance.




Hi Wong,

It would be difficult  as you need the original cable as reference. the reason for it is because Monitor manufacturers do not use standard color code for reference. Please visit this link to see the pin configuration:

The most important signals in CRT Monitor are the RGB, Horizontal and Vertical.





Hi Jestine,

Hope you are well.Just a quick email to ask ,when i am testing voltages in an lcd monitor do i need to have it connected to my pc or can i test without hooking it up to my tower.





HI Shaun,

The best is to connect to the computer otherwise the voltages may drop to half if no signals coming in from the computer.






  1. kevin

    February 8, 2010 at 11:22 pm

    Hi Jestine,

    I have a Samsung SyncMaster 226BW Lcd Monitor ,When i power on the monitor it takes around 3 to 5 minuets to get a screen ,the screen flickers rapidly and slowly the screen start to display my desktop.

    Now this is getting worse and taking longer to display anything, what could be the cause? and will buying your ebook "Testing Electronic Components" help me repair this monitor ,its a very nice lcd with 21 inch screen and i would like to fix this before it dies!

    Thanks kevin taylor

  2. admin

    February 9, 2010 at 8:40 am

    Hi Kevin,

    It could be bad capacitor problem or the backlight have problem. Getting my ebook Testing Electronic Components could help you to test on the electronics components in circuit board. Once you are good in testing electronic components, then only you get the ebook


  3. Henok Birhanu

    April 28, 2010 at 12:26 pm

    Hello every body,
    to all in world am from ethiopia,i need Maintainance books and solutions of electronic devices over all if any one have please let me i will share what i know and what i feel too.

  4. admin

    April 29, 2010 at 11:08 am

    HI Henok,

    I have only the ebooks on the right side of this blog but not maintenance book.


  5. Eng.Mostafa

    October 9, 2010 at 7:45 am

    I am very happy to contact with you
    iam from iraq , iam fresh biomedical engineer in the fact i need to improve my technical skills i hope between your hand i can do ,

    what shall i do to do the best mr.Jestine

  6. admin

    October 10, 2010 at 12:47 am

    HI Mostafa,

    Keep visit forum, read electronics books and magazine on the related topic and practice it. Don't give up easily too.


  7. Tafa

    November 30, 2014 at 3:06 pm

    Thank you for tv repairing advise . I repair tv finesse Utsavi model 3780 fault powersupply but the screen is now showing when using 60watt bulb as fuse. I replace ics and test diots but the bulb light is going deem plus on and screen is on. What are the problem which causes bulb on instead off, then sreen on? Is there still other components with fault?

    • admin

      December 1, 2014 at 9:23 am

      Hi Tafa,

      What is the original complaint and the components you have checked and replaced? Is there output voltages from the power supply or totally zero volt?


  8. Zolani

    February 14, 2021 at 4:46 pm

    Good day
    I have a problem with my tv the power is on but the screen is off
    Model:FN-3780 Finesse UTSAV


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