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Electronic Repair Questions/Answers and Testmonials- Part 64

By Jestine Yong on September 25, 2010

Hi Sir,

Thank you for your reply and thank you for sharing your knowledge you are very generous, thank you very much. By the way your SMPS ebook and LCD Monitor repair ebook are really great! those books really help me specialy the SMPS ebook.

Thank you and more power, GOD BLESS.
Jerry
Philippines

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Hi Jestine,
I repaired the Vizio, had to replace the main board. Customer was happy, and so was I.
Your repair books have really been extremely helpful. Thanks for providing information
for the today’s electronics technician.
Jeff

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

Jestine I have been able to repair the CTC203.The problem was resistor R14115 143k which was opened, and this is located in the Feedback/ Regulation section of the
powersupply .This section is found on page 19 of the manual which I have sent to you.Thank you very much and may God bless you and your family.

Your friend Tyrone.

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

HI Watniegh,

I have the following questions:

1) Can I use the ESR tester to test those large capacitors that are used to start motors used in air condition fans? They range from 10 microfarad to 30 or 40 microfarad.

You can but you need to compare the ESR value with a good one. You need to create your own chart.

2) Can I use the Blue Ring (coil) tester to test those coils on contactors, solenoid valves, transformers used in air condition systems? They range from say 6 ohms to 25 or 30 ohms.

You can try that but as a rule of thumb the coil tested need to have at least .3 milihenry . In other words if the value is too small this coil tester can’t test it.

Jestine

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

Hi Jestine,

There are four diodes D812, D805, D808 & D807. I tried continuity check using the digital multimeter, the neutral of AC supply pin has connectivity to diode D812 anode and D805 cathode. No connectivity to the other two diodes. Can I test diode on board using a Peak Atlas Analyser?

Regards.

Spencer

HI Spencer,

I suggest that you follow the image below and test the output:

http://upload.wikimedia.org/wikipedia/commons/1/13/4_diodes_bridge_rectifier.jpg

For checking diode you need to test it off board. Yes you can test the diode with Peak Atlas Analyzer.

Jestine

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

Hi jestinge
I am receiving one set color tv samsung 21” the problem this tv is no
picture and customer said that her child pour water in tv, but high
voltage and vertical osilator is working and the picture is black I am
changing focus and screen potnetiometer in behind high voltage trans
and the light of tube increase or decrease thenthe part of high
voltage is good I am replace ic number part tda8842 and saa5291ps/099
made phelips company and problem exist yet, I am checking the
transistor around board part number 2sc915 and 2sc 916 were good and
no blow or burn I AM PRESS THE BOTTOM MENU IN FRONT TV PANEL BUT DO
NOT APEAR LIST OF MENU EXAMPLE SEARCH AND ETC ,the b+ voltage is
goodPLEASE HELP ME
HAVE A NICE DAY

HI Hadi,

This will be a complicated problem since the water already poured inside the TV. The menu did not come out means it has something to do with the CPU, EEProm IC and the corresponding components. I suggest that you concentrate on this area as a bad CPU or eeprom could cause no picture symptom.

Jestine
http://www.JestineYong.com

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

hi jestine….

terima kasih atas penerangan carta blue esr yg lepas.

sy ada tv jenis sharp model 20r-sc. gambar tv tersebut menjadi kekuningan. bolehkah jestine bantu sy area mana perlu di fokuskan…? sy dah cek di bahagian crt board…semuanya ok..

jika ikut pengalaman jestine….kenapa ia jadi begitu….?

harap dapat membantu,

terima kasih…

NORRAIMI

HI Norraimi,

Kalau boleh, bandingkan R,G dan B circuit (voltage and waveform testing) di CRT board. Tengok mana satu color circuit yg mempunyai bacaan yg luar biasa. Kamu kena trace dari CRT board ke Jungle IC.

Jestine

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

Dear Jestine Yong,
I have read all your monthly newstellers and i am very pleased with it.
I am an electronic repairer and I deal with flat screens computer boards and power supplies and laptops.
but my major problem is how to read faulty components that have no burnt marks on them. I need a basic knowledge about testing all sort of faulty components especially in lcds and laptop. I will be very pleased if you can help me a little with that.

HI Livingstone.

You need to read this ebook first Testing electronic components because the foundation is in this ebook before you go further to check on the components in those boards. Once you are good in testing electronic components you can visit this website http://www.advancedevices.com/ to get the meter to check on the smd components.

Jestine

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respected sir,

i have measure problem in SMPS is following:

1. not working on load but all output voltage is good and appropriate.

2. auxillary circuit have measure fault.

HI MUKESH,
Check the filter capacitors with ESR meter because a bad cap could cause to have good output voltage but breaking down when there is a load.

Jestine

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This is urgent advise from you pl think about this,my customer give me on supply for repair .manufacture by bailey which is 70 technology ,old model fusible assembly ,showing itermint fault some time its led showing its working and some time showing dead,this power supply used in nuclear power plant ,my question is that if led is faulty which is used for indication purpose its possible because faulty LED supply is gone?my experince is indicate its possable!

Muhammad

Hi Muhammad,

First you need to make sure the power supply is producing output because the LED supply voltage is getting from the power supply. If there is no output then you proceed to check on the power supply unit. If there is output then you tace from the pin of the LED and see at where the signal had lost that made the LED intermittent.

Jestine

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

thanks 4 ur reply
i have the same problem till now…… 15v dropped&monitor led displayed frequently changed like yellow and green. i think may be is this processor complaint?

with warm regards,
M.tamilselvan

HI Tamil,
If the supply voltage to the CPU is good and the h/v signals entering the CPU then most probably the CPU have problem. Sometimes a bad eeprom data may cause this problem too.

Jestine

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greetings. a quick question. when you test the frequency on the crystal in an lcd screen, what setting you use on the oscilloscope…thanks

HI Waleed,

Since i do not have the scope with me (I’m at home) thus i can’t tell you the setting. The setting is actually depends on what megahertz of crystal you are checking. If you got a sinewave, 99% the crystal and related circuit is working.

Jestine

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I want 4 CCFL for a Dell monitor e172fpb, but having problem in finding the
correct size.

Measurement
Diagonaly 435mm
Width 342mm
Height 272mm

Please advice me which ones to buy.

Monitor stays on for aprox 1s and goes blank.
Just replaced inverterboard. same problem.

HI Reidar,

Try contact this website:

https://www.jestineyong.com/?p=2543

to see if they have the right lamp that you need.

Jestine

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

Hi Jestine, Many thanks for your invitation. We will see!!!
I need to ask you a question.
My cook hook works on 3 speed. One and two do not work only on 3 which is fast speed.
I think the variable resistor is kaput!!!!
Am I right to say it is a variable resistor or potentiometer.
I could buy one on internet. Hard to find that stuff.
I am sending you a picture of the resistor which is a green colour.
Hope to hear from you
Many thanks
Regards
john

Hi John,

I have not repair this type of set. If two did not work then you have to trace from the two variable resistor, it can be the variable resistor problem, wire loose contact or even malfunction in the circuit board. You need to take out the two and compare the reading with the one that was working. As for the part, sorry i have no idea where to get it other than to ask from the local electronics store.

Have a good day!

Jestine

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

Hi Jestine,

This philips 107S monitor is working normally, but I see the color of its deflection coil is somewhat different ( grey and almost black ). Is this grey color originally from factory or because usage since 2002? Please see the attached photos.

Bailing

Hi Bailing,

I believe is the original color because yoke coil don’t really get very hot as compare to other components in the high voltage section.

Jestine

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

HI Stephane,

Thanks for your reply. I always enjoy learning from your unlimited knowledge.

Now, four more questions about this decayed glue.

1. How can I remove it without damaging the IC board and/or the surrounding components?

You can scrap it with the help of small flat screw driver and then clean the board with thinner solution.

2.1. Should I put back some new glue (after the removal)?

Not necessary.

2.2. If new glue is needed, what type or brand do you recommend?

Silicon type.

3. What is the purpose of this glue?

To hold or to secure the components from vibration during transportation and also to prevent a component from touching/shorting on the adjacent component

Jestine

http://www.JestineYong.com

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

HI Manuel,

There are many complaints from my customers about the EPSON printers in general. If not replaced the ink cartridges soon and after some time, days or weeks for this replacement, since the machine does not work, or does not print.
Many electronic technicians as well speak of the computer chip that exist in the head of the cartridge and others point to a specific software for its resolution, but still the same and with that, customers opt to purchase the HP printers that do not present difficulties in maintaining .
Here in the workshop I have three Epson Stylus Color 1520 with such problems and would like to see them resolved.
I would like to have your assistance on this technology.

We had try many ways but the problem still persist. The best solution is still to get a new cartridge that comes with a new head. Due to this we do not take in inkjet for repair.

Jestine

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

Hi Durjaykumar,

Thanks for the free book from you. I have a LG home theater system of which the CD/DVD player suddenly stopped once when it was playing a CD. Tried to open/eject the CD out but the tray was not coming out. Suspecting that the switch is NOK and tried with remote also, which failed.The model is LG LH-D6246A. I want to check it myself (wheather the lense/motor/belt is faulty or not) before taking to any repairer. I have interest in doing the checking by myself. I have continuity tester, multimeter and other all size screw driver set to open the assembly. And I have already opened the assembly and separated.

First you need to make sure the power supply is producing the right and stable output voltages. If it can’t eject then it is nothing to do with the lens, you need to concentrate on the switch and the motor.

Now in this step I wanted your guidence how to check which part is faulty ( the poer comes and the display shows always CD/DVD only and motor not moving, I have cleaned the lense also).
Please write me which book from you can guide me for this and also that I will pay using international VISA card form ICICI Bank (or any other way). But help me to do myself.

Sorry i do not have book on this topic. Try visit this website

http://www.repairfaq.org/sam/cdfaq.htm

Jestine

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

Terima kasih banyak-banyak Jestine..Semenjak saya membaca artikal awak, banyak pengalaman baru saya dapat..Saya harap dapatlah awak meneruskan untuk menghantar artikal-artikal seterusnya untuk saya..Terima kasih banyak-banyak sekali lagi.

Oja

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

I have another question! I have an SMPS here that uses Half bridge Topology! It has Two big Filter caps in series after the bridge rectifier. At the center of the two caps where they are joined, Is a high voltage cap 0,1uf that connects directly to primary of transformer. The other end of primary goes to switching Fets.
My question is, what can be considered as the hot ground?
Regards
Riaan

HI Riaan,

Refer to the photo:

http://www.electronicproducts.com/images2/F129ONSE0507a.gif

One of the filter cap negative is the hot ground.

Jestine

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

Hi Spencer,

Does the ebook Testing electronic components you mentioned does cover troubleshooting non-standard components like attached?

Yes it does cover.

I am keen to fix the Acer LCD monitor but encounter alot of non-standard components while troubleshooting. Like in the picture, the resistor like component 0.39 ohm 2WJ (FU77P), I tried using a digital multimeter setting the scale to 200 ohm, I get a reading of 0.9 ohm while using a analogue multimeter setting to X1, I get a reading of 12 ohm.

You need BLUE ESR meter that can measure the low ohm range.

As for the rectangular capacitor 0.33uF 275V, using a capacitance meter setting scale to 2uF, I get a reading of 0.289uF, should be fine for this.

That value is considered marginal. You have the choice to replace it. Although the set can work, may be after 6 months or one year later, this cap could cause problem. Again it depends whether if the cap is located in a sensitive circuit or not.

Jestine

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

Hi Jestine,
How are you and your family. I hope everything is O.K.
Jestine, can you pleas describe exactly how i
must test a flyback with the blue ringstester.
I mean evry handed movement.
O.K. have a nice sunday
Girja

HI Anand,

Just check the primary winding.

Please refer to this link:

http://www.electronicrepairguide.com/testing-flyback-transformer.html

Jestine

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

hello sir jestine!!can u give me some ideas on how to repair a tv which was dmaged due to lightning!!!after the thunderstorm last night, my tv set has no reception.sound is only buzz and picture is totally black!!!!hope u can give some ideas!!!God bless!!more power to your career!!!

HI Marlon,

Usually lightning will strike on the tuner and power section or both. Since your tv has power then i guess the tuner may have problem. Becareful when opening up the tv. if you have no experience i suggest that you send to tv repair shop.

Jestine

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

Yang saya maksudkan dengan down..bila saya switch on tv tu dia ada startup tapi dalam 3 saat bunyi startup tu macam low tapi LED still menyala cuma cahayanya kurang sikitlah.Tapi apabila saya cabut connector yang supply power heater dari mainboard ke crt board tu tiada masalah power low berlaku bila switch on tv.

Hi Noorishkandar,

Ia macam high voltage shutdown. Saya cadangkan anda mengukur voltan B+ dahulu. Heater voltage datang dari flyback dan sekiranya flyback rosak ia pun boleh menyebabkan shutdown.

Jestine

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

sir jestine what are the weakist components in a circuit?

Hi Jake,

Electrolytic capacitors and resistors.

Jestine

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

HI Abdul,

I didn’t replace 7805. I replaced push button for ‘menu’ and the problem was solved.

Congrat!

One more CRT TV had a probem of settings menu frequently popping up with no controls by push button working. I removed all the push buttons as I couldn’t find replacement and the owner is using that TV only remote control. When I checked defective push buttons for short or resistance readings I didn’t find anythings wrong but those buttons were the culprits.

Menu pops up on its own can be unstable in the supply voltage to eeprom or cpu ic, bad data in eeprom , bad crystal , dry joints in the cpu and eeprom area and even bad cpu.

As you know old PC p supplies have -5V at white wire (that was used for old ISA cards) and -12V at Blue wire. 16V/220µF capacitor in the Blue -12V line was bursting whenever I had replace it. 2 FR diodes in the circuits were found good with whatever testing methods out of circuit. I replaced both the diodes and the problems got solved. I remember your clue that components break down with load. But unless we isolate or pin point the particular area in the cuircuit board it may be difficult or take time to troubleshoot.

Good to hear that!

My greetings and prayers for your new book

Thanks!

Jestine

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

HI Dundee,

Hi, sir! I was referred by Clifford Villacampa to you after consulting him
about the problem with my LCD monitor. I have a 17 inch Redfox RF-1799 which
will shut off automatically after I turned it on. It will display normally
when I turn on the power but after 1 or 2 seconds it will turn off. I opened
the lcd and found out there’s a busted capacitor so I replaced it but still
it will turn off suddenly. And after 3 weeks my other 2 monitors with the
same model is also having this kind of problem. I have not opended the other
2 monitors yet. I have been using these monitors for 3 years now.

First try direct replace all the filter caps, second-check for dry joints in the high voltage transformer pins and third- one of the back light may have problem.

It is quite common if one of the backlight have problem the display will shutdown.

Jestine

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

Hi thanks for your support i have fixed that westpool tv, I have one Haier tv i don’t know whether you are use to this tv, it come on but before it start properly the screen blink before it normal, that is the only problem blinking vertical bars, i changed the vertical IC and some capacitors i was thinking to change the coils around the horizontal line and see, hope to hear from you soon.

Abdoulie

HI Abdoulie,

Try place your meter at the SMPS output and power on to see if it stable or fluctuate for a while and then only stable. If you get horizontal bar you should check on the vertical ic, if you get vertical line you should check on the horizontal section. It’s kind of reverse in TV/Monitor.

Jestine

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

HI Jerry,

Can you please help me, I have two problem first I’m repairing CRT monitor with the help of your smps ebook that I purchase but some of the smps in crt monitor have a relay that connected to power section.I don’t know the purpose of this and how to test this, I thought this is belong to Input Protection and Emi filtering circuit but this is not included as you mentioned the parts in input protection and Emi filtering circuit in page 26 of your smps ebook.

Thanks for the support on my ebook. This relay is use to trigger the degauss coil and the signal is coming from Monitor CPU.

My second problem is I found a Fet in AOC monitor 15″ 5en (ST w17347) that connected to primary winding of smps transformer, i tried to test this component with the help of instruction that I got from your website but this fet have a different reading and I thought this is defective because when I try to touch the gate and the drain pin the needle of the tester kick to the center and slowly going back. i tried to test the other fet in working aoc monitor but it has the-same reading. can you please help me and explain this two problem.

Some FET have this kind of characteristic, some will kick up and stay while to some it will kick up and then slowly move down.

Jestine

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

I must let you know I have been blessed from all of your materials. Consequently I wish to seek your professional advice and maybe a possible collaboration.

I have always done my repair work on part-time, that is using my place of residence when less busy after office work. I am having a push and so intending to sent up my own repair and servicing firm. Considering the fact that circuitry of recent are different in Hi-tech from what we use to know, though with same principle, please I wish you could advice me on how to go about setting up a good service/repair centre. though i have a picture in mind.

HI Williams,

Since you are running the workshop from home, i suggest that you make sure your customer base is big enough before moving out to set up a shop as setting up a shop would be costly and i have known few of my repairer friends went back to their home to run the business because they can’t stand the expenses. Make your shop simple but must have the right tools and test equipment to help you out. Your greatest challenge is not on repairing because you can get help from friends, forums, books and etc but on marketing techniques. Without a good marketing plan your business will have to shut down. You must think of ways to increase the equipment that send in for repair. No equipment means no profit.

Jestine

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

Hi yong:Thank you i sucessully download!but still not read it busy right now on my job,I have question about Cap anylzer 88A which desigh by electronic design specialist (www.eds-inc.com) on meter write in circuit DSR,ESR cap analyser 884,what is difference between DSR,and ESR?

Muhammad

Hi Muhammad,

DSR is DC relation to capacitance. ESR is the ohm value of electrolytic capacitor. Thanks for the support on my ebook.

Jestine

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

dear jestine i have a problem in my tv that after a week the horizontal transister failes every week i cheked high voltage capaciter, dry joints but no luck coluld be the lineout put transformer or? pls help

HI,

Try check this link:

https://www.jestineyong.com/?p=403

Jestine

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

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14 Comments

Daniel F

September 30, 2010 at 1:00 pm

Hi Jestine,

Do you know of an equivalent for FA5501A by Fuji Electronics?
It's a Power Control IC from a Toshiba television.

Thanks
Daniel

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admin

October 1, 2010 at 2:05 am

HI Daniel,

Usually it will be difficult to find IC that have equivalent number unless it is from the same family for example SG5841 and SG6841.

Jestine

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Johannes Motsei

October 1, 2010 at 8:57 am

Hi Jestine! How are you today? I hope you are just doing fine.
Can you kindly help me on my home Television Set, which worked fine and until recently started distorting the whole picture and we can even see the normal picture anymore.

The sound is fine; the channels are working alright, except this problem of the picture.
Tweaking the focus and the screen on the flyback transformer did not help at all and there are no signs of visual burned components at all.

Model Name: Panasonic Color T.V
Model: SX 1
Serial Number: 044 00 00

I am still an electronics hobbyist and not a repair technician yet, and still have to buy more books as soon as I can afford from your site.

Kind Regards

Johannes M.T (South Africa)

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admin

October 1, 2010 at 7:33 pm

HI Johannes,

If you have a photo then it will be easier to look at the symptom. There are many type of distortion and is hard to pinpoint the problem if there is no photo to look at. First, have you check that all the output supply voltages from the SMPS are good?

Jestine

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Daniel F

October 3, 2010 at 5:40 pm

Hi Jestine,

I have another problem lcd monitor.
I'm working my way through your ebook lcd monitor repair.

This lcd uses an external power supply which i've tested and is fine, but I've also tried a replacement spare power supply and I have the same problem.

There is partial power to the inverter board but not on all the pins.
The 6 pin connector from the main board to the inverter has 4 pins with 12v but 2 pins have nothing and I suspect that is part of the problem. There is also no leds for power etc lighting up on front panel.

When I checked the voltage on the on/off switch connector pin on the main board it read around 0.4 volt and then shifted to around 0.2 volt when the on/off switch was pressed. So I think the problem is the main board is supplying some, but not all necessary start-up voltages.

The other oddity is that the audio amplifier is getting very hot and you can only touch it for a couple of seconds before it seriously burns.... I know this can't be right!

I read in your ebook that audio amps usually run around 12v, although this does have 12v on the vcc pins, the datasheet for this chip says

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Daniel F

October 4, 2010 at 7:27 am

Hi Jestine,

Since my last post I found a better datasheet.
The problem IC is a LM4838MTE which is a Stereo 2W Audio Amplifier.
It's absolute maximum working is 6v and maximum temperature is

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admin

October 5, 2010 at 8:10 am

Hi Daniel,

Yes it could be the mainboard fault. If the mainboard is receiving all the good voltages then most probably the mainboard have problem because the power LED and the front panel button function all is related to the mainboard MCU. Yes the audio IC usually runs on 12 volt and it should not be too hot to be touched. Try remove the audio ic and power on to see if the monitor will work or not.

Jestine

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admin

October 5, 2010 at 8:11 am

HI Daniel,

How many volt did you get by measuring the audio ic?

Jestine

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Daniel F

October 7, 2010 at 1:16 pm

Hi Jestine,

I'm not sure why my posts were cut off?

Anyway, as I was saying, according to the datasheet the audio amp LM4838MTE has a maximum working voltage of 6v and max temperature of

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Daniel F

October 7, 2010 at 1:18 pm

On another note, you should consider implementing an rss feed for your blog.
I'm sure many of us would find it useful.

Danny

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admin

October 8, 2010 at 9:54 am

HI Daniel,

May i know what do you mean of your post were cut off? I thought i have given you an answer. Okay email me personally at jestineyong(at)electronicrepairguide.com

Have a good day!

Jestine

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admin

October 8, 2010 at 9:56 am

HI Daniel,

Thanks for the suggestion and i have taken note on that. Will let you and the readers know once it is done.

Jestine

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Hussein

November 20, 2010 at 8:29 pm

hi Jestine,
the picture in my tv is shifted to the right and it turns blue after a while...and if i remove the antenna i see a vertical black line at the left...what could be the cause?...
thanks alot for your help!

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admin

November 22, 2010 at 11:02 am

HI Hussien,

I have not seen this problem before but you have to make sure that the power supply output is always good and stable. Make sure the filter cap have good ESR value and no dry joints in the h/v oscillator ic and the tuner box pins.

Jestine

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