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Electronic Repair Questions/Answers And Testimonials Part 18

By Jestine Yong on October 19, 2008

HELLO JESTINE,

YOU HAVE MADE MY LIFE AS A LCD AND PLASMA TV REPAIRER PRETTY EXCITING.TECHNICIANS OF YOUR CALIBRE ARE NOT USUALLY OPEN WITH THE KIND OF INFORMATION YOU SHARE WITH US.THANKS ,AND OF COURSE. I BOUGHT YOUR EBOOK ON LCD REPAIR. I LOVE IT.

M.E

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jestine

I receive my e-book , as for the zener diode tester i don’t have 30v vdc analogue meter can i use for 300 v

Hi A,
You have to use 30 VDC because for a 300 vdc you will not see the small range . Why not modify a cheap analogue meter panel (set to 50 DC voltage) instead of using the 30 vdc panel meter.

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Hi Kurt,

Here are your questions and answers:

I have a question about repairing a LCD screen from acer type (AL718). i have the service manuel for that screen but because the power supply board is from Delta their is no schematic in there. I have this one to repair but after opening i have seen someone else was before me. The capacitor after the rectifier was removed. I did a guess and placed a 100µF/400V. After replacing all other caps (all bad). The monitor works again, but the transformator (into the powersup) is making noise. Is it possible that a wrong choice of the capacitor cause this sound?

Most probable not but you can try a 68uf 400 vdc to see the result.

The noisy transformer gets hots also.

Try knock on the transformer to see if the sound goes off or not. A transformer will usually get hot but would not burn our hand when touching on it. Sometimes a bad components in the primary side (since you said someone had repaired before) could cause high pitch sound from transfromer.

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You know, me also I love the electronic so much but, the problem is I did this profession on direct practical in our local technical work shops. I know the two type of multimeter and the names of all component and how to test them. The only problem I have is how to detect a loosed value capacitor/condenser.

Hi O,
You have to use ESR meter at http://www.electronicrepairguide.com/blue-esr-meter.html

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Hi Mr Yong, please can you send me an article about building an “N-CHANNEL and P-CHANNEL” mosfets test equipment. Thanks

Hi J.S,
Sorry i do not have such schematic.

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Hello sir,

I read article about zener diode tester. It was a nice article. I have a problem with my LCD monitor. When i power on, here are nearly six verticle lines diffrent colors and display is ok. I am sending you two images of LCD 17″ EIZO. Please send me a solution about this problem. I Shall be great thankful to you for this favour.

Have a nice day.

T.M

Hi T.M,
Thanks and i have seen the photo and the problem is in the LCD panel. I have seen few of them but not in the eizo brand.

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hi Justine,

Your technical support give me satisfaction. I want to know how we make Electronic CRO to check the output signal of Electronic board.

Have a nice Day……….
Ur Friend,

P.P

Hi P.P,
Sorry i do not have information for this electronic CRO.
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Hi Z,

Here are your questions and answers:

i would like to ask about filament supply transformer did you have a picture of this.

Sorry i do not have, i heard those days electronic shops did sell transfromer filament booster.

and what kind of transformer is this?

I believe to boost the current filament voltage to higher value.

and how effective the crt restorer from anatek tips and tricks. can i have a picture of how to restore the crt step by step using this or your own crt restorer if not this one.

To be honest many current tubes can’t be save by using the crt restorer. I’m using it to confirm if the tube is okay or not. Sometimes after the rejuvenation test the tube get even worst. Some tubes after restored could only last for a day or two due to the internal getter material inside the tube had been use up and could no longer absorb the gas.

thanks very much.God bless you more.

You are welcome!

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Hi Jestine,

I came across one unit SONY Color Television (Model KV-J29MF8S) which has color problem that I have not come across. What do you think is the fault? Is it the degaussing coil malfunction or convergence circuit problem?

Please comment.

Thank you.

Hi R,
If the degausser (demagnetizer) can’t remove the color problem, suspect a faulty tube.

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HI there,

I am still not understand to test SCHOTTKEY and how to test regulator in ATX PSU PC on . How to test importand componet ATX PSU pc, psu is running (on).

Regards

Hi Danny,

Set your analogue meter to X10 K ohm and test on the schottyk diode. it should show one low ohm reading and one slightly high reading. If you get two identical reading then it is consider shorted. May i know what regulator you want to test-any part number?

The important components to test is the electrolytic capacitors. You need an ESR meter to do the job. Please visit http://www.electronicrepairguide.com/blue-esr-meter.html

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Hi Johnny,

Here are your questions and answers:

Please let me whether I should attend your class or just purchase your Ebook ?

Attending class involve of practical work which you can grasp faster then reading book. You can see, touch, and test the actual electronic components with all the ready available meters. If you attend my class i will give you this ebook for free.

If I purchase your book can it readily help me to repair as quickly as possible?

Not as fast compare when you attend the practical lesson. The reason i sell this ebook is for international market because they can’t come to my centre to take up the courses-very costly!

Is your book only teach how to repair monitor?

My book is about testing electronic component. Once you are strong in testing electronic components and know the safety, in fact you can start to repair any electronic equipment

Can I also learn how to repair TV and other electronic equipments later after reading your Ebook.?

You must first be strong in Testing electronic components. If you are interested in tv repair then get a book on TV repair as this way will help you more in that field.

Although I have learned about electronics during the past but it just theory only.

I was in your boat before

Is this Ebook the first book for the beginner who do not know about electronics repairs ?

Yes, absolutely for beginners and intermediates

How much is your Ebook ?

USD37.00 or RM120.00

Do your ebook teach me the step by step methods?

Step by steps in testing electronic components and some basic troubleshooting

Lastly I am a retired electrician and wanted to learn more on how to repair any electronics equipments so that I can be a service man to earn some money.

Good to hear about your plan. Yes we can earn part time by repairing electronic equipment.

Most importantly, I would be grateful if you can give so discount on your E book.

This is the best price i can give as it comes with my lifetime support in order to make you to be good in electronic repair. Most other people either no time for you or just don’t want to share their trade secrets with you. If you have any electronic repair questions just email me. With one or two repair, you can actually cover the cost of the ebook.

Have a good day!

Best regards,
Jestine Yong

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Hi Loh,

Here are your questions and answers:

In one of your article you mention the capacitor is to block DC allow AC & the coil is to block DC allow AC current to flow.

Is it correct?

Well, it depends on where the capacitor is located.

Because at your free report for switch mode power supply page 2,the DC output from full wave rectifier is DC Which will be filtered by a 220 micro farad capacitor will produce a clean DC output make me confuse. Since the large capacitor will

Block DC allow AC if like this how possible the output from a capacitor will be a clean DC voltage.

In this circuit-we call it as filter circuit. A capacitor is needed to stored the DC voltage and remove the ripple produces during the conversion in the bridge rectifier. Capacitor has other functions too like waveshaping and in timing circuit.

Hope this helps!

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Hi Jestine,

I saw your website and was very happy to learn of your service.

I am interested to learn how to diagnose and repair old amplifiers and speakers.

I was wondeing whether you conduct intensive 1-week course on diagnose and repairing hi-fi.

If you do, please let me know as i am really keen. Maybe I can take a week off to learn from you.
By the way, i have a spoilt AR amplifier, i think the model is AU.

I am trying to get replacement transistors for it but unable to find them in Singapore,

do you have them? The model number written on the transistors are : 2947 and 2919.

I hope you can help. Thanks very much and have a great day.

Regards,

P.C

Hi P.C,
Thanks for your interest in my website. For your information i do not repair amplifier because i don’t get the chance to repair one due to my business nature is in computer related items. For the courses, i only conduct the basic electronics, crt/lcd Monitor and printers. you may check out at http://www.noahtec.com/workshop.htm

As for the parts, sorry my side do not have any of them. However if you have any electronic repair questions like smps and monitor, you are welcome to email me. Thanks!

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Hi R,

Here are your questions and answers:

Oh I see, could be the picture tube is faulty like what you said.
Yes

I am sorry yesterday I quoted to you the wrong TV. It’s not SONY, it’s China made CTV, the brand is ‘HesStar’. I confussed it cos the same customer sending 2 TVs at one time.

No problem

In fact the problem of SONY TV that I mentioned is having no picture. When I check the B+ voltage at Pin 2 of the flyback, the voltage is correct (135V), and it stays after switch “on”. But the voltage at Pin 4 (200V supplied to picture tube PCB) drops to 135V after few second of switch “on”. The same goes to Pin 6 Heater voltage (around 10 over Volt AC) and Pin 9 voltage (15V) both drops to 0V after few second of switch “on”.

Could it be the high voltage have shutdown? You need a high voltage probe to test the KV out from the FLYBACK anode.

Jestine, any idea what made them (voltage) drops? At first, I suspect the picture tube is faulty. But when I tested those voltage again, with picture PCB detached from the pictue tube. The result is the same. Any comment?

If high voltage shutdown, it could be the flyback itself have problem, an open safety capacitor, dry joints and etc.

By the way, our normal multimeter can’t measure the heater voltage due to that it is a high pulse ac!

Best regards,
Jestine yong
http://www.JestineYong.com

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Hi Danny,

Here are your questions and answers:

How to test volt for regulator PSU ATX 400 watt when PSU runing ON.

These are not regulator and can’t be test when power is On

Regulator part number : PFF2N60 – KSH13007A – KSH13007A

For your information the PFF2N60 is a FET and KSH13007A is bipolar transistor. Please refer to my ebook on how to test them.

I have 12 unit PSU rail is down but all part number SCHOTTKEY all diferent Regulator part number all diferent. What common part number for SCHOTTKEY and REGULATOR power suplay ATX 400 watt.

Different model have different part number. There are just too many part numbers in the market.

How I can change componet,

Use a solder gun and a desoldering tool.

I can’t find part number for all componet.

Is all written on the components the part number.

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Hi S,

Here are your questions and answers:

Thank you for the report let me give a brief summary about myself.

You are welcome!

I have done Diploma in Electronics Microprocessors ,i know how to test i.e resistors,diodes,transistors e.tc but the problem i dont know how to fault find problems in switch mode power supplies,recently i got a temporary work as a Power supply techncian i have dione some with visible problems i.e rectifier is dead,capacitors have blown off, but reading how the voltage and current moves its still a major problem. So i want you to teach me online how to repair a power supply,then monitors e.t.c showing me schematic diagrams at the moment i have 4 power supplies of different CPUs testing fuse,brdge rectifier,switching transistors because they have 3 transistors at the input and 3 back to back diodes at the output(its like transistors) they are all working perfectly but the power supplies they are not switching on.

Repairing power supply is a big subject as it involved lots of circuits and components and due to this in fact i’m writing my fourth ebook which is “Troubleshooting and Repairing SMPS” .

In your case, you said it does not switch, did you have check all of the components in the primary side? Sometimes a shorted diode in the secondary side could prevent the SMPS from working too. By the way the 3 back diodes is actually a schottky diodes and you need to check for any short circuit.

tips : If the power supply have no sound at all-concentrate the primary side. If the smps have high pitch sound, concentrate on the secondary side. Since smps have lots of e-caps you need an ESR meter to do the job right. Hope this helps!

Best Regards,
Jestine Yong
http://www.JestineYong.com

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Hi E,

Here is your questions and answers:

I have a Mars Foxconn motherboard ,i have a problem with this mobo , in a few words this mobo looks dead , I already check the Seasonic 650W PSU two times with a tester and the PSU is OK , i swap this Foxconn Mars motherboard and installed a older Foxconn 945P7AA motherboard and the PC with this Foxconn 945P7AA motherboard is working normal OK ,can you tell me please if there is another way to check the conditions of this Foxconn MARS mobo before I send to RMA ? ,

If all the e-caps looks good then sorry there is no other way to check other then to use a post card to find out the fault. Click on the link to visit the website for more information

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

I am sure now the lack of power is not due to a faulty PSU , because the PSU Seasonic 650W energy Plus is working fine when I install the old Foxconn 945P7AA motherboard ,but when I install the MARS mobo , the blue led of the Foxconn MARS mobo dont turn on ( when I switch on the Seasonic 650W PSU ) ,none fan spin , all is dead, I swap the memory RAM module with another RAM module ( all RAM modules are 1Gb DDR2 800MHz ) but the blue led of the Foxconn MARS is still dead , may be I need to swap the processor CPU with another CPU processor ,all this was after a possible short circuit between the northbridge of the MARS motherboard and the motherboard tray ,can you tell me your opinion please ? , thank you

I guess it could be some serious short circuit in the motherboard. Remove all socketed components even the cables to harddrive ( left only the plain motherboard and power supply) and power ON. If the problem still exists, i guess you have to replace a new mobo! Hope this helps!

Best regards,
Jestine Yong
http://www.JestineYong.com

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Dear There,

I need book to learn about testing common all componet to repair for Monitor CRT and ATX PSU with multimeter and picture. I need book step by step to complete repair monitor CRT and ATX PSU, I will buy if you can make it to me. I have internet public cafe and all users pc using ATX PSU and 15 unit monitor CRT and 10 LCD. I need to repair 12 unit PSU ATX and 5 unit monitor CRT, because I can’t repait that 5 PSU and 3 monitor CRT I was give to someone else to repair that and I spend 100 USD.. I have now modem ADSL dareglobal and Ethernat hub 16 port to repair. I will pay you if you can give ebook to repair that all.

Nice to know you.

Hi D,
Sorry i have only two ebooks that suit your requirement

http://www.TestingElectronicComponents.com and

http://www.LCD-Monitor-repair.com

I do not have the CRT Monitor, ATX power supply and ehternet hub repair book.

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hi again
How can i find this diode? (HZ16-3L) everybody we don’t have this diode
thank you.

Hi I,
Sorry my place also doesn’t have this part number. Why not try 16.5 or a 17volt zener diode to test it out.

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I have a Princeton 20.1 I replace a bunch of bad caps in it and it has a high pitched squeal, not real loud though. What components squeal? Which component should I suspect as the one squealing? I made sure they are all installed correctly (polarized correctly) I did replace a 470 mf 10 volt with a 470 35 volt and a few others with higher voltage from 25 to 35 volt.

Any help appreciated.

Danny.

Hi Danny,
Try read this post at https://www.jestineyong.com/?p=1226

and

https://www.jestineyong.com/?p=938

By the way, the higher volt in capacitor won’t cause it to have noise.

TWO DAYS LATER Danny replied:

Cool. It was the small transformer, not the large one. So just dip it in clear shellac you get from a hardware store and let it dry overnight? Does it not mean that the transformer is bad and needs to be replaced?

Sometimes bad surrounding components could cause the small transformer to make sound. If you have confirmed that the transformer is the cause then yes, dip into shellac and let it dry overnight. The transformer is good, but it just that the internal winding may have loosened that cause the vibration that produces the high pitch sound. Since the transformer is working then it is considered as good.

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Godbless you and your hand works
i didn’t thought about it you did in advance very clever thank you let’s be patient.
Mr. A

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

Hi A,

Here are your questions and answers:

I am struggling with a monitor to make it working. Monitor is dead. I checked and found that horizontal output transistor is shorted and a cap on the vertical stage is buldged. I replaced vertical IC, Cap and line output transistor. When i applied power it comes ON. However, this monitor did not last for 5min before it dies again.

Is the HOT replaced are original number? The B+ voltage to the HOT have to be according to spec. If the B+ voltage slowly getting higher the HOT will spoil again. Check also for an e-cap that is connected across the supply line to horizontal driver transformer too.

I checked each and every component, i can’t find exactly what is problwm. When i checked across the mains filter cap, voltage is flunctuating with a ticking sound. I tried to replace suspected component on the primary stage but didn’t help. My problem now is that i don’t have idea which stage is failing or causing this fault.

You can separate the circuit by removing the B+ coil aned connect a 100 watt bulb between the B+ supply line to ground. If the bulb blinks or shutdown that means the problem is in the SMPS side. If the bulb stays fully bright only then the problem is in the flyback or high voltage area. Hope this helps!

Best regards,
Jestine Yong
http://www.JestineYong.com

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

hi good afternoon! Do you have the in circuit capacitor tester diagram?

Hi Baddy,

This is the Blue ESR meter diagram:

http://www.anatekcorp.com/Blue%20ESR%20assembly%20manual.pdf

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My Eddy Current testing instrument input wrong power supply and damaged the powerpack but the instrument have a over current protection. There is current output to + 5V, +- 15V & +12V. Could you repair such power pack?

Hi R,
Sorry we don’t repair such equipment. Try send it back to the manufacturer or you can try repair it yourself. If you have any questions, i can assist you from the email.

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Hi D,

Here are your questions and answers:

Having trouble reading a matallized Polyester Film Capacitor. I believe it is. Its read I cant find out what the first letters and numbers mean. I know what the second set is do you know what they mean? The internet explains most but not all.

F 40 (What does F 40 mean?)

683J ( I know what this row means)

Also another one;

PE (Don’t know what the PE stands for???)

472J (I understand this one)

50V (And this one obviously)

Ceramic Disk Capacitor

E (What does the E stand for??)

103M (I know this one)

1 KV (I know this one)

SEC (What does SEC mean?)
You answer can be found here at http://www.hitano.com.tw/pdf/Y2.pdf

This is Blue High Voltage Ceramic Disk and numbers are

AH222M (What does the AH represent??) –Please refer to the above answer

Is M the tolerance %? Yes it is 20%

X1:400V (Is this max voltage??)-

Y1:250V (Minimum Voltage??)

Please visit this link for the answer:

http://www.coilws.com/AppNotes/Line10.html

Hope this helps!

Best regards,
Jestine

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Dear Sir,

Thank you for the e-mail that you send and also about the electronic circuit that you have given to me freely. I have to be very grateful to you because of your generous heart that God has given to you. I will continually pray for you so that the God will reveal more technical matter in the filed of electronic. By the way, let me request some technical matter from you. If it is possible, kindly compile a report on how to make a PCB by using the UV light system. This will help most of the students to make their own PCB. Previously, I use the lettering to draw on the vacant PCB but now there is no opportunity for us to buy the Lettering. Basically, if we want to use the UV light system, we have to design our own printed circuit by using suitable software (e.g. PCB Designer Software). I hope that sir will try your level best to compile a book or report on how to use the software until we get our own Printed Circuit Board to test. Hope this idea will bring benefit to all of us. Thank You and Wish You All The Best!

Best Regard,

R.D

Hi R.D,

Thanks for your email but sorry i do not have any experience in using the UV light system to make PCB. May God bless you too.
========================================

Hi Jestine,

Thanks for your newsletter. It has been very helpful to me in my repair works.

Patrick

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Hello, Mr. Yong

I have little confused about I saw two products which you have “product that
call testing electronics comp” and “lcd monitor repair” I am very beginner of electronics things. So, which one I supposed buy to learn how to fix my lcd monitors?

Please let me know which one I have to buy.

Thank you,
N.T

Hi N.T,
Thanks for your interest in my eBook. If you are a complete newbie then you should start with the Testing Electronic Components eBook first. Once you are strong in testing electronic components, in fact you can start to repair any electronic equipment. Then your next step would be getting the LCD Monitor Repair. If you carefully read the website in LCD Monitor repair, it says that “This E-book is written for those who already have some experience in electronic repair and for seasoned electronic repairers too.”

If you have other questions please do email me again. Thanks and have a great day!

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Hi T,

Here are your questions and answers:

I am asking your advice and expertise as to what this problem could be.

I have a RCA Flat Panel T.v which has an orange light on the front. When I press the power button the light turns to green, then back to orange and flash four times. The model number is L32WD22. What does the blinking orange light mean?

Since i do not have this 32″ RCA repair data but the blinking light and led turned from orange to green could indicate faults in the inverter board , main power supply (not the sub), in or problem in the microprocessor itself (mainboard problem). It seems that the main power could function well (green light) but because of something shorted upfront (probably in the inverter board components) the LED turned to orange again. It could be the main power supply itself have problem (unstable) that triggered the microprocessor to output the blinking signal. Hope this helps!

Best regards,
Jestine Yong

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sir good afternoon,i like to ask coz my tv brand TCL was struck by lightning there was no sign of power id like top ask what was the problem?

thanks,

edwin

Hi Edwin,
If struck by lightning, then i guess you have to open up the tv cover and check all of the primary part. Start with the fuse first.

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Hello Jestine,

I like to hello to you thanks for the great information about lcd
and plazma tv, although I have been in the repair business for other 20
years this new technology. would be hard to learn unless we had good information which you provide
so thanks again
N.H

Hi N,

Here are your questions and answers:

How are you today?

Fine but a bit busy with my fourth book. Hope you are fine too in Australia

I need your help again and I hope you don’t mind.

No problem!

I will go straight to my question as I know you are very busy.

Busy but still have the time to support members.

I’m fixing a HP 5500 CRT monitor. After it warmed up it cannot display anything when you are using 800×600 resolution or DOS or full DOS in windows ( I mean after running CMD and then pressing Alt+Enter). But it worked perfect on 1024×768 resolution. Observations I had are:

– Switching from 1024×768 to Windows full DOS ( or 800×600) give no display. But if you turned off the power of the monitor even for few seconds and turned on again it can display the DOS ( or 800×600). It will continue to display DOS till you change to 1024×768 and then back to DOS again.

– If I restart the computer, during the part the the display is not 1024×768 there is no display, but display appear once windows is already on 1024×768 resolution.

-When monitor is first turned on after overnight off, DOS and 800×600 are fine, only after monitor is warmed, but 1024×768 has no problem

-During the time that there is no display I’m sure there is high voltage and filament voltage. Power led is green (when its on standby it turned amber) so it don’t go to standby. If I pull the power cord during the time that there is no display I can hear the high voltage shutting down, that’s why I sure there is HV.

Where do you think I should start ? I suspect EEPROM but I’m not sure. What’s the best way to pinpoint the faulty component ?

First you must make sure the output voltages from the power supply are steady (test the voltage with analogue meter and make sure the needle constant)

Next-make sure also the 5 volt to the micro p and the eeprom is steady too.

Check components in the s-correction (resolution circuit) area like the FETs and non-polar caps

If all tested okay then direct replace the h/v oscillator IC and retest again.

If the problem still persists then suspect either the micro-p or the eeprom.

Hope this helps!

Jestine Yong
http://www.JestineYong.com

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

Hi Dave,

Here are your questions and answers:

I have an older Sony tv and when I turn it on the picture take a 5 minutes to come on. Then it comes and goes for another ten minutes. I really like this TV and would be a shame to through it away. Any thoughts?

Most probably dry joint in the CRT board area (heater/filament circuit). Apply fresh solder on it and it should be okay. Check also for dry joints in the flyback transformer pin.

Notice that my email has changed. Can you update your data base.

Sorry Dave i can’t update the database manually. What you need to do is to click on the unsubscribe link in the repair newsletter that i sent you. Then please visit this website:

http://www.electronicrepairguide.com/electronic-repair-newsletter.html

to resubscribe again. That’s it and has a good day!

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

AP2761I-A – Do you know of a cross number that would work?

I found this mosfet shorted in an LCD power supply. Can’t find it anywhere. Do you know of something I can use in its place? Why would such a common component be so hard to find? This is just a simple switching power supply component….

Any help would be appreciated. I have looked everywhere for this part.

Thanks

Hi H,
It depends how the electronic suppliers source for the parts. For your information i could not get this part too. Try 2sk2645 for substitution. Although the volt and ampere smaller by 50 v and 1 amp, sometimes it can be use too. You have to test it out and see the result.

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

Hello , Thank you for your message , I am here in London UK , how much cost your book in british pounds ? , is possible to buy your book in a book shop ? , thank you

Actually my book is an ebook thus you can’t find it from bookstore. That means, once your payment is done using credit card, you will get a special download link and you can save the ebook (pdf files) into your computer. You then can read from the screen or print it out and bind it as a book. The book is USD37 which equivalent to about 21 pound.

About my problem with my faulty motherboard , please can you guess which component of this motherboard was damaged due to a very low voltage short circuit between the” Back side ” of the northbridge touching the metallic motherboard tray of the case ? , now the computer looks dead , none fan spin , none beep , no standby LED light on when I switch on the PSU , all is dead , but I am sure the Power Supply Seasonic 650W is 100% working properly , thank you

I have been in the motherboard repair before and all components ranging from small capacitor to big ICs can be the suspect. Please read my blog here at https://www.jestineyong.com/?p=1018

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

Hello,jestine

Could you please tell me where i can get a high voltage probe to buy reasonable. Thank you.

Hi C,

Try http://www.Tenma.com

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

Hi A,

Here are your questions and answers:

Thanks for your good tips regarding the acer with tic tac sound , as you told me that the FBT I had sent to have no problem so I thoroughly checked the power supply side and I found the culprit. I checked the HOT C5929 and seems to be ok but I forgot to check the emitter – collector when I checked it and I found that it was opened. It should be one side got reading and the other side no reading am I correct.

It depends on part number, sometimes at x10 k both also no reading but then you can use your finger to trigger it. You can refer back to my ebook on how to trigger the transistor.

Thanks also for info regarding the zener diode tester,when I checked 5 V zener with my analog multimeter it was ok but when I checked it with zener diode tester it was opened when apply voltage to it. Replaced the new HOT and 5V zener solved the tic tac sound.

Wow! that was interesting!

For your info after I sent the FBT to you one customer send the same brand acer monitor with no power for repair and I use the FBT to test the monitor with tic tac sound and it works ok after the HOT and zener replaced. For the no power problem only the replaced the opened fusible resistor solved the problem.

Congratulation!

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14 Comments

vhusi

May 12, 2010 at 3:44 pm

Good day,
What can i replace the power mosfet a2761i on my Dell LCD? i cant get it from the local shops around here

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Reply
admin

May 13, 2010 at 3:07 am

HI Vhusi,
Sorry no info on that part.

Jestine

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Reply
Rosauro Ponce

September 11, 2010 at 9:24 am

Hi Jestine !
I would like to operate a 110 volt TV set from USA to work on 220 vac supply. I'm planning to change the input capacitor(just after the diode bridge rectifier) working voltage to 400 vdc and replace the diode's PIV rating to 400 vdc.Are these modifications enough to make it work? Hope for your kind comments ! More power and success to all your undertakings !

Thanks,
Rory Ponce

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Reply
admin

September 11, 2010 at 10:28 am

HI Rory,

If it use power FET then you may need to find one that can withstand up to 600vdc.

Jestine

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Sheila

October 30, 2010 at 3:00 am

Hi! First of all, i found your site very helpful to many electronic enthusiasts. Thank you for starting this.

I was searching for a possible replacement or equivalent of PFF2N60 but can't find anything in the net or in ECG. Do you have idea what can be used to replace this part?

Thanks!

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admin

October 30, 2010 at 4:18 am

HI Sheila,

May in know where was the power fet located and in what kind of equipment? It could be a 2amp 600 volt n -channel FET.

jestine

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Mushfiqur Rahman

October 30, 2010 at 12:25 pm

Hi Jestine,

Thanks for your cordial response. I have posted a problem about LCD monitor on a thread but since I am new here that's why I couldn't find that thread that's why asking again in this thread.

Sorry for my disturbance.

Last day I said that my ACER AL1916w monitor is showing the green LED indicator when I connect it with the AGP(or VGA)port and it's remains green(LED). If I remove the VGA cord from the VGA(or AGP) port after sometimes it's led become yellow. In both cases nothing shows in the display.

To solve the problem I removed the metal cover and test the power section. I found that the backlight CFL is not getting their voltage. Actually they are getting 0 volts.

I thought that may be the step-up transformer(FBT) which is dead and that's why it's happening. But after removing that from the circuit board I've checked it and it's ok. I have also checked the caps and they are ok and showing their respective voltage.

I am a student and that's why it's not possible for me to go a repairer cause of heavy charge. I would be grateful if you help me.

Thanks.

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admin

October 31, 2010 at 4:19 am

HI Mushfiqur,

The ccfl not working was due to that mainboard did not send an On signal to the inverter IC. If the VGA cable is connected and the POWER LED light turned from green to yellow then this mean the Micro controller (MCU) programs may have corrupted. It is the mainboard problem since the MCU is located in the mainboard.

Jestine

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soorajkp

December 30, 2010 at 10:28 am

from ur site i come to know the substitute for ap2761ia and let me find the mosfet and i get back to u after replace ment.
thanking you

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manju

November 3, 2011 at 12:01 pm

Hi sir manjunath here from Karnataka belgaum dist Dell E172FPb LCD Monitor (Benq OEM) c5707 transistors I change the this transistors but same problem continues power batten led blinking whats a problem tell me sir

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admin

November 4, 2011 at 7:55 am

HI Manju,

You need to check for shorted fet transistor and make sure no dry joints in thew high voltage transformer. Make sure also the tuning capacitor value did not out.

Jestine

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Jaylan

December 1, 2011 at 1:58 am

Hi sir have a wonderful day,
can you help me pls?.. i have TCL-2009 tv crt. my problem is NO POWER BUT THE LED IS BLINKING, I replace already the control ic TDA16846 but still not working.
may i know sir if what is the common proplem regarding with this issue?.
thank you so much and more power.

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admin

December 1, 2011 at 3:41 pm

Hi Jaylan,

Try use the link below to isolate the problem:

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

Jestine

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Jaylan

December 1, 2011 at 11:47 pm

Thank you so much sir for immediate response..more power.

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