Electronic Repair Questions/Answers and Testimonials – Part 26
I just want to wish you a Merry Christmas and a happy new year. I thank you for all the help you provided though out the year and May the lord bless you in a mighty way.
I have read your book so many time and every time I learn new things. I printed out all the books you sent me and I made folders out of it and add them to my library. they are wonderful and I thank you for them. I have fixes so many lcd monitors and tv’s and I am loving every minute of it. the victorious moments when that lcd monitor comes to life is beyond any description. God bless you my friend.
How you doing i hope verything willbe ok.
‘MERRYCHRITMAS and A HAPPIEST NEWYEAR’.I wish the coming year will be a year of pease,wisdom and achivement for you.,for you are such a wonderfull kind of person.Jestine i don’t know how to thankyou and appriciate you for the aids, theaching tips and helpfull comments you are giving to all of us.As a thechician all those tips you are sending to me are very,very helpfull,and i am using them as i can THANKYOU again jestine.
HI Jestine, can you tell me where i can get a reasonable laser power meter to buy, also some tv/monitors schematics . Thank you. C. P
The tv schematic you can get free from http://www.eserviceinfo.com and the laser power meter i guess you have to email to this website http://www.sanwa-meter.co.jp/overseas/product/laser/laser_list.html
Here are your questions and answers:
hi thanks for free report .please i would to you to send me report on how to use transistors in power supplies and other circuit
Sorry i do not have report on how to use transistors in power supplies and other circuit. i guess you have to refer back to those basic electronic books. Normally when a transistor bad , we just go to buy the same part number and replace it.
and also the equivalent of this horizontal transistor c3997
Thanks so much for your help! I really admire your philosophy of lending a helping hand to other aspiring repairers.
It’s too bad
How are you Mr jestine young, I am very happy to meet you in internet.I am a Technician (electronic) field in sri-lanka. And I want to thanks for your electronics guides, I learn lot of things about lcd, fly back tester,esr meters,moniters circuites and so on. and i want your help forever. I talk about you with my friends,you are a great man in electronic Field Thankyou very much.
Here are your questions and answers:
Thanks for all the materials. I successfully downloaded them all. I am just getting started with this
Thanks for the support!
, so I would like to ask you a question. I have a 17″ Norwood Micro LCD monitor that i am fixing for my first project. It has a flashing power LED, and the on off switch works. When you switch it on, it makes a faint clicking sound, and one of the CCFLs briefly flashes, in rythem with the clicking sound and flashing power LED. I followed your test sequence:
Fuse is good, voltage in and out
filter capacitor is good.
secondary output voltage is good
Since just one of the lights flashes, and the other CCFL is also good, I’m thinking it is the inverter circuit. I have attached a picture of the power board, and the side that doesnt work is on the left on the picture. I think the inverter is the one marked UT35D82. After this, I’m stuck. Am I on the right track?
If all the output voltages are okay then suspect is the inverter circuit. First the supply voltage to the inverter ic has to be stable. next you can compare the components resistance between the top and the bottom lamp circuit. Any difference in the resistance then track from there.
Thanks for your help, I like your writing and instruction style.
You are welcome!
If you were in
Ha -ha i got a cheap labour!
Also, could you recommend a good Oscilloscope? I am looking at a tektronix 485 that goes to 100mhz. Will that do?
Tektronix is a good brand and 100 mhz is good enough for electronic troubleshooting work.
Also , do you have a cheaper way to test capacitors on the board other than the Capanalyzer 88A? It is just not in my budget right now..
What about the Blue ESR Meter at
I have a good digital MM, and I ordered an analog one. I have also just bought a DC power supply, 0-38V 0-15A. I am planning on getting an oscilloscope and a flyback tester as well.
If you got all the good tools and test equipment in fact you are ready to troubleshoot any kind of electronic problem. Investmentin tools and test equipment is always good for electronic repairer.
what do you recommend for soldering/desoldering?
Hakko 981 solder gun and any branded desoldering tool/pump.
What else will I need as far as tools?
Those common one like cutter, long nose plier and etc.
Thanks again, I’m having fun!
If you have other questions please do email me again and you have fun too!
Here are your questions and answers:
Every day I surf your blog to learn something new, especially about Question and Answer. I do take note about every troubleshooting technique that you use. But because it is not my problem, I sometimes don’t get what your explanation in the answer. For example, the question goes like this:
I have a fairly new Samsung 2493HM 24in LCD that powers completely off for no reason. You can turn it right back on and it will stay on for hours again. Any idea what I should look for that would cause this?
It powers down completely just like you turned it off. No power light. You touch the power light and it fires right up to a big beautiful display and runs again for hours. I just spent 210 bucks for it and donʼt even know where to start to find this issue. I thought it powered off all the time when I bought it but every 2 to 4 hours sounds hard to diagnose.
Dry joints and sometimes it could be a bad mainboard. Bad mainboard can cause no Led OUTPUT thus you thought it was no power. To confirm this you need to check the output voltages.
Right Jestine, the first pin of the PWM IC is connected to the primary ground. Before I didn’t do it accurately. By the way, do you know the tips to open the case of the printer or laptop power pack? It seems to be dead-sealed.
The tips is in my blog about using petrol on the edge.
My friend’s 15″ CRT monitor is not having any display when connected to computer, but the indicator lamp do turn green from amber while booting and when there is signal. The strange thing is that I could not hear the inrush current when switching it on. What could be the problem?
A missing B+ voltage to flyback transformer and missing drive signal to base of Horizontal output transistor.
how you doin?
it’s me from
i’m an electronic technician that i repair crt tv etc. these days there are lcd, plasma tv, i want to request to you to help me in the matter of lcd and plasma or if there is any suggestion for me.
i’m grateful to you
Thanks for the emails and i guess the best for learning the lcd and plasma tv is to join my friend Mr Kent membership websites at:
Thanks and have a good day!
I found a bad 2.4 M ohm resistor and naturally didn’t have a replacement. So I used 2 1M ohm and one 470k in series. Is that ok to do that in a circuit?
Yes you can but i guess a 390k is more better than 470k. Or you can get a 2 x 1.2 m resistor in series.
Just found my first shorted component using the variable DC power supply trick! J Cool!
I have a Dell 17″ Model P790 monitor. It doesn’t show display(Monogram).
Screen shows light but no display. Power OK, Horizantal voltages ok.
Please guide me, where is fault in this monitor.
Have a nice day.
Check all the RGB signal from the video pre amp ic to the RGB points of CRT board. It should show some signal with oscilloscope. Make sure the video pre amp have correct supply input.
DEAR jestine i want to test an opto-isolater as you described in your book but can i test it on board or i have to remove it thanks a lot
You can desolder one pin at each section (the LED or the Transistor) to test it without removing the ic. As for me i prefer to solder it out and test.
I have a question pertaining to the Blue ring tester. Can I test automotive relays or aircraft magneto coils with this tester?
Thanking you in advance,
I’m not sure about these two components. According to the spec it is designed for B+ coil, flyback, smps and crt yoke coils. However i could also test it on the ballast/choke of the fluorescent lamp. One of my buyer told me that he could test the coil of the ignition in the car. I guess you have to get one and test it out. If you have other questions please do email me again.
I have a monitor i was repairing,it dont have power but i heard sound on the flyback section its like a clock ticking.can you tell me where is the problem of this one
It could be the Horizontal output transistor shorted or the flyback internal capacitor shorted. Sometimes it could be a shorted secondary diode too.
Dear Sir :
Have a nice day to you…….this week i have encountered a problem of a 17″ crt monitor that the menu will automatically appeared on the screen without pushing there buttons
and some icons inside the menu will be adjust sometimes decrease and sometimes increase
this type of trouble i never encountered before ever since…………
Sir maybe you have encountered this trouble already may i need your support and consideration regarding these matter………thank you very much
Try change all the front button and clean up the eeprom and MCU/CPU IC area. If it still the same then i guess the eeprom data had been corrupted.
Thank you for your reply, I do not have a digital capacitance meter but I do have a Blue ESR meter. The capacitor test about 0.16 which I guess is ok for 47uf.
I have continued to be impressed by your web site and service; therefore I intend to purchase the test electronic components E-books later tonight.
Thanks for your support and yes the 47 uf have a good ESR ohm reading. You may visit this link to download a chart which is easier to read at:
I just received a new CCFL for a laptop and I want to know if it’s possible
to do a continuity test on it. Just to make sure it’s in good condition. I
want to execute this test because I also suspect a faulty inverter. So,
using this inverter to test my new CCFL will be of no help.
I already tried to execute a continuity on this new CCFL by setting my
multimeter on the continuity test option and applying the red probe to one
end of the CCFL and the black probe to the other end, but nothing happened.
The multimeter still displayed “1” (no beep).
If its not possible to do a continuity test on a CCFL, is there another way
to test its condition without using an inverter?
Sorry backlight (lamp) can’t be test with ohm meter. and the best is still have to test it with a working inverter.
Here are the questions and answers:
Pls forgive me for breaking my word not to ask you more than one question at a time.
1) Are there any other PWM ICs other than UC3842 and KA3842 and what are their part Nos beacause I’ve seen in Satellite receivers & DVD players and many other p supplies an 8 pin IC in the primary side. Some have different part Nos and some have part Nos erased by the manufacturer.
There are many part number use in the smps section in many different types of electronic equipment. Some example are UC3843, UC3844, AP1200-40, SG5841, SG6841 and etc.
2) an old COMPAQ CRT monitor takes time at start up to put picture and brightness on the screen. What could be the cause?
Weak pc tube or low heater voltage. The heater voltage should be 6.3 volt.
3) STALLION new CRT monitor has no brightness and proper colour. All the control panel adjustments are fruitless. What will be the reason??
make sure all the voltages at the crt socket are good like the R,G,B G1, G2, and heater.
4) Now I know why you stopped shipping parts. But in future if I require 2 to 5 pieces of each parts that are mostly used in (You’ll decide what parts, you know well.) HP, DELL, ACER, VIEWSONIC, SAMSUNG LCD monitors can you buy and ship them in bulk, of course with your profit.
I need to know the parts first before i can quote you. Another option is to email lavinci at email@example.com to ask for the parts.
To buy Blue ESR and RING TESTER form you and save 39$ courier charges to UAE I’m still looking for some one like UAE students studying in Malaysia to buy the meters through them. If I find a proper person and send you his mailing address can you please ship the meters to that address?
Yes no problem.
Pls let me know when your book is ready for sale.
One thing I’ve to mention here is that I found many spelling and grammatical mistakes (excuse me) in your e books and bonus reports. Well, English is not our mother tong and every human is to err.
Yes, infact English is my secondary language and my primary language here is Bahasa
Sorry for the late reply as i was on
i have read your article to check non polarised capacitor testing by using dick smith esr meter is it possible to check same with blue esr meter.waiting for your earliest reply.
thank you sir,
Yes it is the same when test with Blue ESR meter.
Thanks for the greenlight of using the testimony. Here are your questions and answers:
As you’ve always told me that I should set some goals to achieve for every year that comes by, I am set again to set my goal(s) for the year come 2009.
Yes one have to set it so that they can look forward for their achievement. Otherwise tomorrow will be another same day and same routine again. Once you have achieved your goal, the feeling will be beyond description.
I want to integrate programming skills with electronic skills. I am thinking to build any electronic device and programme it to serve a purpose as would be needed by anyone in this modern age of technology. How do I go about that?
To that end I have enrolled in one IT College here in
Sounds good to integrate the programming with the hardware. I once done that before during my college days and was using the c++ language to communicate with the outside world. I have forgot all the programming because my concentration was in the electronic repair. Ask from any institute that provides this type of training and i have no idea of which college is best for this from the internet. If there is a robotic course then i suggest that you go for it.
All the best!
I would like to learn about troubleshooting computer motherboard(as in check for faulty capasitors,faulty connections etc etc) and graphics card.Do you conduct such customised courses?
Thanks for your email but sorry i do not conduct such course.
Hi Mr. Justine
How are you?
Do you know transistor J6810A?
May I get the manual, coz I can’t find it from internet.
what’s the similiar else with J6810A?
thank you for your help
I’m fine thank you. Sorry i do not have the spec of j6810 but i use c5411 as replacement. Hope this helps!