Don't Miss

Electronics Repair Questions/Answers and Testimonials -Part 69

By Jestine Yong on December 4, 2010

Hi Jestine

I hope u and family have a very nice time on the island and it’s good to see u are making the most of life, and taking time with your famly, i downloaded your ebooks,
TestingElectronicsCompoments and ElectronicRepairArticles and they are the best articles i have ever been able to understand, you are truly a sincere and wonderful person.

I am grateful to have people like you, who are totally unselfish and share there knowledge. People like you really do make the World a better place.
Thankyou Jestine and best wishers and all the best.

Dennis B Far North Queensland.

============================

Hi JESTINE!

You are just a “GIFT FROM ABOVE” to me!

I got the ebook 2days ago, but now i can assure you that i have already discovered some tricks which have been a problem in ATX Power supply units.

This book is applicable in every electronic equipment ( medical instrumentation, analytical instruments, PCs, Printers and industrial control). Again thanks!

Sincerely,

Christopher

================================

Hello Sir, How are you

I am very grateful to you for your easy guidelines on Electronics through your e book. Hats off to you Sir.

Thanking you Sir

regards

Noor A , India.

=============================

Hi Jestine,

Just want 2 find out from you whether you have a simpler yet effective method of testing crystal & mc44603 pwm i.c..

Thanx..

Gerald

HI Gerald,

For a crystal you can build a crystal tester to test it but usually is not that accurate. Preferably use an oscilloscope to test it when the power is on. For any PWM IC the best and effective way is still to use a scope to test it. Nowadays there are many used scope for sale and the price is less than RM500.00 for a 20mhz scope.

Jestine

===========================

Hi Jestine,

I am gaining a lot of information from your website and from your eBook lcd monitor repair ….. Thank you so much.

Edwin R

Philippines

===============================

Hi jestine yong i have problem with my monitor which is of CRT type
whenever i switch my PC monitor screen displays monitor is ON check
cable.
What may be the problem.

HI Suleman,

It could be the cable not properly connected or the internal have wire broken or even bad cpu.

Jestine

==========================

Hi, Jestine,

your ebook in smpsrepairbook is very interesting, help a lot in improving my knowledge in smps.

rgds,

Benjamin

===========================

Dear Sir Jes,

Just a while ago I was called to look at the church computer monitor and when I arrived I saw the AOC 19″ monitor is powered up but half of the screen has a white band horizontallly in the lower portion. Just want to ask you, if this problem can still be fix? Thank you.

Daryl

HI Darly,

Yes it can be fixed, Check for dry joints in the vertical output IC area and make sure the supply voltages to the vertical ic is good.

Jestine

==============================

Hi B,

Before I regard the capacitance value below 1.5 nF, the problem related to it must occur/ manifest whether tic tic sound, the display disappear for a moment etc; but I had repaired 2 CRT monitors having 0.5 nF internal capacitance value, yet the monitor is still working fine. How do you explain this?

For monitor that have use the internal capacitor as a feedback, a 0.5 nf cap will cause the monitor to shutdown. For a monitor where the internal capacitor is connected to ground it can cause tic-tic sound and if it does not cause any tic tic sound, i believe after Monitor use it for couple of months it can become shorted.

How to know if the internal capacitance is open or short- circuit; what are the display reading of the capacitance meter respectively?

Open- use digital capacitance meter (lower value than it should be for an open cap)

Short circuit- use analog meter set to X 10k ohm range and should have no reading on both ways.

Jestine

================================

I must testify, that your write -up is good to a beginer like me. Who want’s to excel more in electrical/electronics. But , i still need an article that can help me to found the equivalet of an electronic componet like transistors, ics etc . I would appreciate to hear from you. Have a nice day.

HI Leo,

To find equivalent part number usually i will use the equivalent databook which is easier and faster.

Jestine

===================================

hi, jestine, is there a good meter for measuring crystal devices?.if there is, i will like to order one.thank.

Hi Temp,

The best is to use scope. My digital meter have the frequency measurement but usually digital meter range is quite low. Even you can build a crystal tester kitset but the range is still low.

Jestine

================================

HI JESTINE,

Thanks a lot for the monthly repair tips it realy help me a lot on my personal repair reference.but this time i realy need your expertise, i trouble shoot a sharp cinemaborg 21 inch tv.the problem was the IX1791CE was shorted.before i replace the shorted ic i check all the electrolytic capacitor at the power supply section,and check all the sorounding component on it after checking i install the newly purchase IX1791CE and power up the unit.the unit was operate for only 1 hour and the IX1791CE ic was become shorted again.i just want to ask you what was the other possible trouble aside from the IX179CE. the heat sink of the power supply unit will run hot for just 10 second,can’t be touch by the hand. but i still power up the unit until it goes shorted again.is there possible also that the IC I purchase is not an original?

HI June,

There are few reasons like the quality of the IC, supply voltage too high, load circuit took up too much current and etc. Try place a heatsink with heat compound on the IC and retest again.

Jestine

=============================

Hi i have a benq fp71g+ lcd with power problems its shutting down(screen and power light turns off) suddenly after a few minutes then comes on again shortly or after pressing some buttons. I noticed two mosfets(2sk3484z) have caused the pcb to change color, I’m confused i haven’t tested the mosfet yet checked the caps near the back light circuit it seem to ok no bulging(esr test .01 – .04) Please give me some suggestion where to start?

Thank you,

A.C. Samuel

HI Samuel,

If the output voltages from the smps are good after the monitor shutdown then suspect the mainboard have problem particularly the MCU programs may have corrupted.

Jestine

=================================

hello sir,,
thank you for the news letter….sir i just want to ask my dvd player 2 years old when i insert dvd disc no disc appear even a new dvd disc but when i insert mp3’s and vcd’s it read..sir why do you think the problem of my player?is this laser?
hope you help me sir
thanks a lot

HI Jayron,

Check or replace the spindle motor because a slower speed could cause such problem.

Jestine

===============================

Hi Ajayi,

What is the best way to keep motivate when do jobs likew LCD repair. I lose my motivation when i dont get result.

Many times i have failed too but i never give up. Even if you can’t repair the equipment but along the process of repairing it you have learned something new. Always make yourself better than you were yesterday.

I have a 50inch Lcd.When i press the power button i hear the start up sound but no vision at all. Can you advise!.

Is all the output voltages from the smps good?

Dose a diode have many reading like when the red probe is on the cathode while the black probe on tha anode, i get a reading on analogue meter!. Many thanks in advance

If you test a normal diode with Sunwa analog meter, yes there will be reading if the red probe is on the cathode and the black probe is on anode.

Jestine
http://www.JestineYong.com

===========================

Thanks Jestine for resending me the link, I couldn’t wait to see if the “power supply repair guide” lived up to the things said about it, my conclusion after going through it, was it is completly true and is a must for any one interested in repairing tvs no matter what level of experience they have, in time I will get the other books ,so I can have a well stocked reference library ,again my thanks regards john have a good day

John

=============================

Hi Jestine

Can you please help me to identify this part. I cannot get a datasheet for it. It comes out of an LG tv and if I test the volts on it I get 110V on leg 1 and 8V at the middle pin, leg three is connected to ground. I appreciate your help allot.

May GOD bless you and your family

Willie

Hi Willie,

Here is the link:

http://pdf1.alldatasheet.com/datasheet-pdf/view/38239/SANKEN/SE110N.html

May God bless you and family too.

Jestine

===============================

Hi Ng,

Q2. I mean this black squad component and it label Analog device 118A (Please see attached picture), so I can not really test it without the info. How do you test or comparison, Can you give me some clues please, thank you. This board is from Technicon Colorimeter.

That means if you have similar working board, you can solder it out and put on the bad board and retest. If it works then the existing Analog Device have problem. But you need to have a working unit.

Q3.Sorry you are right, it is below 217( Please see the picture attached), it also label NS 237 LM308 AH

It is an operational ic and you need another good one to compare it. You can access the info below:

http://pdf1.alldatasheet.com/datasheet-pdf/view/70230/LINER/LM308.html

Thank you very much for helping me, I really appreciated.

Best regards
NG

=============================

Likes

(0)Dislikes

(0)

4 Comments

philani

December 19, 2010 at 8:21 am

hi just
my compuctor block it fan and distroy my number of monitor but its power LED show that its take power but no trammision fro the monitor
please help

your regard
philani

Likes(0)Dislikes(0)

Reply
jitendra upadhyay

December 20, 2010 at 3:36 am

jesting thanks for share your jurney experience

first of all thanks for such helping all people , i am computer motherboard repairer since long 8 to 20 years if u have any questiong for me u can ask freely
now my question is for you from where i can purchase lcd monitor fet inveerter transformer and smd component for the same
i have CRT monitor make vewsonic model E71B it is giving plane raster no any image it seems to be currupted memory data so how can i reprogramme that memory ic

jitu

Likes(0)Dislikes(0)

Reply
admin

December 20, 2010 at 6:34 am

HI Philani,

Could you elaborate? What is the complaint of the monitor?

Jestine

Likes(0)Dislikes(0)

Reply
admin

December 21, 2010 at 6:10 am

HI Jitendra,

For the inverter parts you can email Luca at info@lavinci.it . As for the memory, you need a programmer to do it. You can visit http://www.lancos.com

Jestine

Likes(0)Dislikes(0)

Reply