Electronic Repair Questions/Answers and Testimonials- Part 34
Sorry for disturbing you, I need information from you since my fellow worker did not boarder to help me with monitor testing points, so please if you could help me in this matter. I just need the voltage testing points like where to start using testing meters and which parts to start with.
Your kind help will be a blessed one.
Thank you and hear back from you.
Study the lcd monitor repair ebook on how to make the voltage testing then open up a working crt monitor and test it at the CRT board with the help of any CRT monitor schematic diagram that you can easily download from free website. The CRT board have points which is the socket points. Those points are the R, G, B, Heater, G2, G1 and ground.
I’m to see you keeping it real and enjoying the finer things in life. It is those things that keeps your sharp to produce the wonderful newsletters.
Good morning and thank y for yr LCD report.Since 9 month I havent get good connecting to internet.Y know I stay in Yangon.Now I am abroad working on the ship.We have Internet on the ship.And i have one CCTV monitor problem.I will try after read.Monitor is blinking picture after few second.Picture come on and off frequently.
Make sure the smps output have a steady supply-check all the filter cap that have high ESR with ESR meter.
And I also have a problem with one radio(GRUNDID YATCHBOY 500).When I tune the station station signal is always switch to USB mode.I don’t have a circuit drawing .I could not get from internet also.
Since i’m not in this field i can’t provide any expertise advice on this subject.
Can y give me an idea how to get a circuit and how to trace the fault.I do not do for business ,my own hobby.My professional in Electrical Engineer on the ship.
This TV Set is giving me nightmares. The problem here is that, I don’t have a schematic diagram at my disposal and don’t know where to get one from?
Have you try http://www.eserviceinfo.com ?
The brand name of the TV is not classified among the well known brands on the market. The name of this TV is seen on the front face as “ ECCO”. I have tried
In vain , on the internet to find out , who the manufacturer is and I do not receive any feedback. AS a result, I am not sure where the CPU gets it’s power from? Presumably, the CPU at this stage, is not receiving the 5volts needed to activate it since the LED light does not come on and if the CPU is not on, then my guess is, the set will not work. Am I right?
Yes definitely the cpu must get the 5 volt supply in order to work and the LED signal is coming from the CPU ic.
I am pretty sure that the SMPS transformer, on the primary side, is in working order., but on the secondary side, the voltage reading is very low. Do you perhaps think the SMPS transformer is shorted?
There is also a possibility as i came across a Compaq Monitor that have low output voltages and found that the primary winding have partial short when test it with Blue ring tester.
And if it is, how can I know this to be for sure ,since I don’t have a LOPT/FBT tester. I know about the Dicksmith LOPT/FBT in –circuit tester, but right now I don’t have it. I have had this TV set for more than a month now and my friend, perhaps wants to relieve me of the problem, would like to send it in for repair. I told him to give me a little more time because I will not allow this problem to defeat me.
Have you try the isolation method where i sent you the link yesterday?
But you know , I have realised something. If your troubleshooting knowledge about TVs is limited, I guess when one is confronted with a problem such as the one I am going through, then it’s going to be very tough.
Isolate the Tv first and see if the low output voltage is cause by high voltage area side or the smps itself have problem. Have you check all the secondary side filter cap with esr meter?
Thanks for sending me the manual once again now I made a print and a CD .I have a quire regarding LCD monitor is as follows..
In LCD monitor main board it has a power supply i.e DC-DC converter.I found 5 to six capacitors Tantalum having high ESR values.Does the ESR values for aluminum cap(Normal electrolytic) apply to Tantalum capacitor are these values same or different.I use a Dick Smith ESR meter .
I rarely come across board that use tantalum thus i can’t give a specific answer to you. I guess the tantalum capacitor is okay because it cannot be all have the same high esr value. Try solder out one and test the capacitance value. If it is okay then most probably a good tantalum will have slightly higher esr value.
Hallo Mr, I want to ask, lcd monitor 17 “acer, horizontal white lines, what is broken?
LCD panel problem and need replacement!
hi jestine. i have problem solving one of this hp 19′ lcd monitor. the power led is ok, and i check the power board and it seems ok too. but there is no display. your suggestion would be helpful thanks.
If there is voltages into the Mainboard then suspect Mainboard problem. This problem is quite frequesnt in Hp and Acer model.
Do I need to have electronic experience to learn how to fix lcd monitor’s. thanks
Yes you must have at least some basic electronics in order to repair the LCD Monitor. You can try out my other ebook first Testing electronic components. Once you have completed reading and practicing from the ebook and good in testing electronic components you can start to repair LCD Monitor. If you have other question please do email me again.
Hi Mr yong I am pleased to have you communicating.
I would like you to assist me know the pin connections of vga cable.
I will be grateful when that is done.
have a nice time.
Try check this http://en.wikipedia.org/wiki/VGA_connector
Hello Mr. Yong,
Good evening, I name is Steve. I’m one of the customers that purchased your E-book. I am new at this hobby (electronic) and after I read your courses I have a great understanding of what electronic are about.
I’m try to be brief, would you tell me how to use a Capanalyser 88A ESR meter. I just bought one on-line and all this is new to me. Please, give some examples how to test a capacitor by using the 88A ESR meter? What to look for and how to read the chart on the ESR meter?
Thank you so much for teaching me. I hope in the near future, you would have courses like your e-book on DVD as well.
My order # is MJE9WB5Q
Thanks for the support on my ebook. Yes to read the chart is easy. The chart have green , yellow and red bar. Green means the cap is okay/good, yellow means the cap is marginal (if you did not replace it , maybe after few months the same cap will give problem) and lastly the red bar means you have to replace the cap because the cap is in bad condition (high esr value). Assuming you are checking a 100uf -cap and the result was green bar so this means the cap is good. You can test it on board or off board. If you have other questions please do email me again.
to day i completed my esr kit and for frist time in the history of this esr i check one un used
electrolitic cap 470 microfarad 63 v belongs to shoei company
meter read .08 standard table say more than 0.1 reading cap is not good
the question is what do you suggest because of slim diffrence between standard and wirtten amount by meter do you keep the cap on duty or you dismiss the cap
If the cap is in a sensitive circuit (like in power circuit) then you have to replace it and if not you can ignore it. Or you can take this as general rule, if any cap reading that is above from the chart just replace it so that we will have the piece of mind that the equipment that we have repaired will not come back for warranty claim.
thanks again . i add some foto to testify that i have done my job.
Thanks for the photos -good job!
Hi Mr jestine
There was a short circuit problem happened
during I measure on the legs of the IC No.LM1236DMA,
Led to the loss of raster. the input voltage became about 4v.
So what’s the solution? Do I change the IC? Is this the IC
could be the reason for no picture and the lighting(raster) problem?
Yes it could be and you need to replace the ic and retest again. I have changed several of this IC. If you have the scope then you can easily confirm if it good or bad.
hi mr jestine.
i have test a optoisolator.when i connect black probe of my analoge meter
to collector and red probe to emitter of output section (transistor) then
meter pointer move on two way. (the meter is on 10k )
part number is “pc123”.
is it spoilt?
thanks a lot.
Yes it is spoilt. A good one should have only one or no reading in either way.
I just opened LCD today and I found nothing of Capacitor leak and burnt condition.I can make out power supply board.I can’t make out inverter area.Logic area and main control processor area I can make out.Pls advice the fault,sympton is monitor is on and off frequently within 3 minutes.
Tin Maung Than
First is the output power supply stable when the monitor was on and off? If yes then suspect a bad inverter board/ mainboard. If no then check on the power supply especially the filter cap.
Sir good pm. I would like to ask the switch in the attached file(see the attached circuit) about the switch is it a two single pole double throw switch.What is the meaning of the dotted line? is this mean two single pole double throw connected? can you explained sir about the switch in this circuit. Thank you sir.God bless you more.
I’m not sure about the line but it seems that this switch is a double throw single pole. Please visit this link. Wow you seems like to build transistor tester from circuit diagram
Hi Jestine Yong,
thank you for sendimg me the May news letter, i hope you will send me more because it could help me a lot.
you know i really want to learn more about trouble shooting and testing electronic parts since i am having hard time doing repairs and testing electrnonic parts.
I am currently working in an fm broadcast radio station and sometimes our transmitter equipment is in trouble and its very difficult for me to do the job,but your help i hope it wil become easy for me to do so.
thanks more power and god bless
Visit this link http://www.repairfaq.org/REPAIR/ and study it. This website helps me alot.
Thank you for sending May 2009 newsletter regarding main board repair. Really I believed that without especial trouble shooting instruments for TTL IC’S is hard to detect faults. We always asumes by replacing it with another one which is in good condition..It is also my problem here in Saudi Arabia since usually spare partsd is not available in the market,and we usually depends on the broken boards which we can remove IC on it.Oftenly I repair motherboards here for laptops which from dead set units.. I am not afraid opening it since it is already dead set and mostly having power problem.
Thank you again ang regards..more power to you.
I have a problem and would appreciate any help.
Recently, my Dell 1504FP LCD Monitor is dead. After I pressed the on/off button, the on/off button keeps blinking (blinking orange light in on/off button). The LCD has a slight hissing gas sound whenever the on/off button blinks. After blinking for sometime, sometimes it will stop and the light goes off. The screen remains black all the time (screen has same look like no power).
A few days ago, whenever the on/off button blinks with orange light. I would on and off (the on off switch on the main power supply) the monitor for a few times and sometimes it could still work as normal if I am lucky.
Could you advise me what is the problem? Is it the capacitors problem? My monitor is about 2 years old
Thanks a lot.
It might be the filter cap have problem and you have to test it with esr meter. The best is to open up the monitor and make sure the smps is producing good output voltages. If the output voltages are good then suspect a bad mainboard.
I am in the process of repairing a Samsung 913V. It has exactly the same problem as your “Samsung 713N with OSD problem”.
It appears that the main board is faulty. Do you know where I can find a main board or the MCU?
The best place is still getting it from the Local Samsung Distributor.
Hello,Jestine.I cannot explain how thankfull I am feeling within me.
First ,its been a very big struggle with the network in trying to subsribe with your website.Secondly I encoundered lots of challenges on downloadig these very important information.
Today Im very happy because I managed to Download all three pdf’s you sent me:How I can repair Benq&The Acer 17″ LCD Monitor , Monitor preview book , & Interview with proffessional electronic repairer.
Lastly I read your 7 Tips advice.Its very good (usefull) to me.
I am very very thankfull.Bye,Happymore.
Are these repair solutions similar across other models such as DELL, IBM and HP?
In fact LCD Monitor is easier to repair than CRT Monitor. And yes many of the lcd although are different, many of them have common fault.
I am not an beginer here and would like to buy your repair book but I am concerned and it being a real usable tool.
I am been unemployed for a year and doing door to door sales the last 6 months and have very little funds to work with now so I am very cautious.
It comes with my support to make you a professional in lcd monitor repair.
It seems hard to believe that people will pay to repair their LCD’s when new ones are $150 to $200 for 22″ screen
I suspect the average repair bill is $50 for 17″ screen. Can you share some wisdom here?
It happens in all country just do not charge too high. Charge a reasonable price.
Also, does this repair solution work with laptops as well?
It works for the laptop lcd screen and inverter but no the laptop motherboard.
Do you have a seperate book on laptops and laptop LCD’s?
Sorry i do not have.
If you have other questions please do email me again.
1.Dell 15′ model:E152FP #display cutoff after few(2-3sec)then blinking
Make sure the inverter ic is still receiving the supply voltage when it cut off otherwise suspect a bad mainboard. When blinking is the output voltages still good or fluctuate?
2.Compaq 15′ model:TFT 5015m #display(background brightness)too bright-in2-3sec n contrast(wording) turned to blur,so just wander u got such experience??reply ASAP if got any solutions.Tq Hew
If all the output voltages are good then suspect either the Mainboard or the lcd panel have problem. Make sure also the flex cable between the mainboard and the lcd panel is connected properly.
(1) i need you to recommend all the equipment needed to start the repair work of LCD monitors , currently i don’t hv anything with me
I suggest that you start from the basic first by getting this ebook Testing electronic components Once you are good in testing electronic components you can infact start to repair lcd monitor. The test equipment that you need are :
Blue ESR meter
Blue Ring Tester
Analog/Digital multimeter and
Digital Capacitance meter.
(2) do you actually provide courses in
if yes, pls provide the detail, i might be interested to attend depending the duration
Yes i provide only the Basic electronics, CRT/LCD Monitors repair courses but not the computer pcb boards repair. Please visit http://www.noahtec.com/workshop.htm
Saya Ahmad, 1.Saya nak tahu sama ada C5706 boleh dibeli di pasar road
Saya tak pernah beli C5706 kerana biasanya saya guna C5707 dan didapati dari supplier lain. Cuba tanya kat RE.Spares pasar road, kemungkinan mereka ada.
2.Apa Jenis fuse 2amp (FP751) Secondary side. LCD DELL, Model M E152Fpb
Pico fuse tapi kamu boleh guna fuse fast blow.
3.CRT Monitor Acer AC 713, masalah tiada display, B+,Screen, Hot,Heater 6v ok,tetapi lampu di neck tube malap dari biasa
Ada high voltage tak (24 kvdc)? Kalau tiada high voltage, gambar tidak akan keluar.
4.CRT Monitor Acer AC 511, masalah display Terlalu Terang dan Ada Vertical Line, Grid negatif 0v, tetapi di flyback ada voltage -160v.
Grid 1 tak sepatutnya 0 volt. Kamu kena trace dari point grid sampai ke kaki flyback. Kemungkinan salah satu perintang sudah buka.
I have a monitor (proview) that only blinks when I turn the power on.Can you give me some tips as to what to check first?
It can be IN any section like SMPS, Secondary section, shorted HOT, FLYBACK AND YOKE COILS and etc. Try visit this link and isolate the problem first.
Hi, Jestine thank you again for the newsletter. it gets good every time. You are really bailing us out.
The newsleeters are very educative and I am sure my fellow suscribers are making the best of it..
Keep it up, and may god bless you.
HI, MR YONG
I RECEIVED MY METERS WITHOUT PROBLEM……….THANKS VERY MUCH……
GOD BLESS YOU ……FOR…… WHEN I ASKED YOU A FISH, NOT ONLY YOU GAVE ME A FISH BUT ALSO YOU SHOWED ME HOW TO FISH……..
GOD BLESS YOU
AOULOU MOH MAXIME
Hello jestine, how r u? Actually, I am facing a problem with my voltage regulator. I just make a simple circuit from Transformer->brigde rectifier->voltage regulator(simple power supply circuit). I measure the input it gives me 12V but when I measure the output it only gives me 3V. I used 7809 regulator. When I change the regulator to 7805 it still gives me 3V. I replaced with 7812 also gives 3V. Is that means all my regulator was leaky? when I tried to connect with load, it also gives 3V. the input of all regulator I measured was fine. How is this could happen?
thank you so much and have a nice day! (^_^)v
Does your circuit consist of filter capacitor (470uf to 1000uf 25 volt)? What is the amp of the transformer? When the voltage regulator outputs 3 volt what is the input voltage -still 12 volt or had dropped to lower voltage? I need these info to help you out fast.
what is a isolation tranformer,is that just a tranformer or 220v to 220 v transformer,any diagram of it,
It is just a normal linear transformer that have ratio of 1:1. That means if 240 volt in then there will be 240 vac out. Here is the schematic:
Dear Justine,i managed to assembled the two meter and function well,just have to getting how to make use of it,
i can delay to repair the compaq monitor later,but i have a batch of likom L505 14-15″ monitors,do you have any experiences repair with those models,i have some symthons to share with you hope to have some advice from you,
one unit is the capacitor 104 burn and catch fire (after i changed a new one),it is located after the 4 ac bridge diode.
one is when switch on ,got power on can heard click sound from delay and raster but all immediately just shut down by itself.
one is no power ,and i changed the HOT Transistor (the old one all short within the three pins) can sw on but still no display.
and still have many of them that can sw on with power but no display,if you have any idea pls advice me or if need more details i can email you with some photos.Thank in advance.
This model had stopped coming in to my repair center about a year ago. Normally to isolate this type of problem we remove the B+ coil and connect a light 100watt light bulb between the B+ line and cold ground. If the light is ok then we can say that the smps is working fine and problem lie in the flyback area section and if the lights blinks or no light at all then we have to check all the components in the smps.
By the way is the monitor have any high voltage when you say no display? I need to get more info in order to help you out.
saya ingin bertanya tentang tv
kerusakannya ada pada flyback (BW02526), dan saya ganti dengan yang tidak original, dan itupun atas permintaan pemiliknya. tapi setelah flyback di ganti, gambarnya menjadi melebar ke kiri dan kanan, apakah itu di sebabkan oleh flyback yang tidak original.
Ya kemungkinan kerana sekiranya inductance value pada kaki flyback adalah berlainan dari original. Kamu kena compare inductance value tresebut.
bagaimana caranya agar gambar menjadi normal, apa yang harus saya setel?
Kamu kena cari flyback yg original
dan di mapa persamaan transistor C5928, saya cari di situs data sheet juga tidak ada (monitor AOC).
Saya pun tiada tapi anda boleh guna C5411 dan
dan persamaan transistor KSC5802 (monitor LG)
kenapa sewaktu monitor saya hidupka pakai PC tampilan bios nya mengecil, sedangkan tampilan windows nya normal, bagian apa yang rusak?
Tiada benda yg rosak kerana bios dan windows adalah berlainan resolusi. Kamu kena adjust gambar tersebut di dalam OSD sewaktu gambar itu sedang boot.
I am Goodson M working for
am a Chief Technical Officer I have these two LCD Monitor that I need
Nice to know you.
1. Philips LCD Monitor Model ID 170SFB/00
Serial number: BZ000452225894 Manufactured December 2004
Has the Following Problem:
The Display is ghosting leaves shadows around pixels.
If all the output voltages are good then suspect a bad lcd panel.
2. BEnQ LCD Monitor
Manufacturing Date: December 2005
Serial Number: ETNC500439SLO T
Problem: No power
Have you check all the components in the primary section? Is there any output voltages from the SMPS?
I bought your LCD ebook last year and I don’t know how to troubleshoot
these two LCD monitors after Reading the ebook. As for the BENQ LCD
monitor I found two Diode and transistors shorting in the inverter
The transistor is C5707 2x
Do you have any ideas what I should do or Equivalent replacements.
For this part the best is to use original number. Equivalent number can’t withstand long and will breakdown soon. You can order the part from http://www.bluestar-online.com
I should be very grateful to hear from you. I am new in repairing LCD
If you still have other question please do email me again.
hi mr jestine.
some of bjt transistors exist that have internal diode between collector and emitter(catode to collector and anode to emitter).
for example:”tip120″ transistor.but some of datasheets haven’t equivalent or internal circuit of the transistor !
how can i find internal circuit of all component in order to i can test components exactly ?
(since if i haven’t been internal circuit i consider components under test with ohmmeter are spoilt.)
thanks a lot.
You need a semiconductor databook as it will let you know if the transistor has diode in it or not. The best is to find the original datasheet from the manufacturer.
It’s always a blessing to have your answer to my every question. Your reply really encourage me to venture in this repair line.
You are welcome!
When I practise to open my Samsung CRT SyncMaster 765MB monitor, I happened to see the big filter cap bulged ( 270uF400 V ), but after taking it out and tested it with blue ESR meter, it has ESR of 0.13 which is unexpectedly still good. Do you think I should change this filter cap since the capacitance is very rare ( 270uF ) and I cannot find it in the local market ( See the attached photo ). Or do you have any other method to judge whether this filter cap is still good or not?
The cap is already have problem due to overheat that had caused it to open up. The reason why the esr value was still good is because it have not reach to a level that make the esr value to go high. Normally when i see such cap i will straight away replace the cap without checking with esr or digital capacitance meter. Yes you can test it just to get the knowledge of the characteristic of a bad cap.If you can’t get the 270 uf in fact you can install a 220 uf or a 330 uf cap but with the same or higher voltage rating.
This monitor also has metal shielding surrounding all the pc tube and boards. Could I power this monitor on without this metal shield ( still doing the repair ). There is contact fin around this metal shield to make contact with the pc tube and CRT board shield. ( See the attached picture )
Yes you can power on without the metal shielding. Quite oftem we throw away the metal shielding.
Reading your recent Q&A about using monotor blur buster in the TV, do you mean that this MBB method is applicable to big TV screen, but is only applicable to small (15″) monitor?
Yes it is applicable to big tv screen but not too big. I have tried on a 25″ goldstar and it worked perfectly good. Normally bigger tv screen have higher anode voltage which this mbb may not take it.
Is the method of using light bulb when repairing CRT monitor is also applicable to repairing LCD monitor?
Yes the series light bulb trick is applicable to all electronic equipment smps.
Could we change the non polar cap with the polar one in doing the monitor repair, because we could not find the non polar cap in the local market? Is there any side effect?
Depends on circuit. You have to try out and see for yourself if it works or not.
Is the convergence yoke the same with deflection yoke?
Yes they are the same and it depends on technicians which term they prefer to use it. I prefert to call it as deflection yoke.
Do you often need to change the yoke when repairing.
No, if the yoke have problem we will replace the whole pc tube. It is not encourage just to change the yoke only as the convergence will surely out of alignment and difficult to tune it.
Is the one that we often test ( 4 pins socket ) only relate to deflection yoke?
Then how to test the convergence yoke?
Since convergence meaning is the same as deflection yoke then the testing is the same when you test on deflection yoke. For your information, convergence is a term for the three colours to converge and focus on the phosphor.
Do you know where in the net I could find more information regarding the yoke?
Sorry i do not know. As far as i know many electronic repair technicians hardly know how to build websites thus they could not relate the information to users except to forum. If there is no question from the forum members then there will be no answer for it.
I want to findout,How to go about testing a diode without using a multimeter.And which other instruments can be to test a Diode.
The best way is to use multimeter to test a diode
Hi can you please tell me if the Sanwa XY360TRN analogue
multimeter the wright meter is to buy for testing
transistors etc. Thank you. Willie Bruwer
There are few version of this meter. If the meter have the X10 K ohm range then Yes that’s the right meter to check on transistor.
Dear , My guru
Hello Mr. Jestine. i receive tv from consumer with no osd. picture and sound ok. TV ( Tennox) have jungle IC (LA76810A). Please your suggestion.
No OSD could be fault of Crytal, CPU and EEPROM IC (data corrupted).
Thanks! I just tried to post this to your blog but the website isn’t co-operating. Here’s my comment/question:
Hi Jestine – thanks for posting this info and making the free report available – very useful information and I am considering purchasing your book.
I’m trying to fx a Hanns-G HC174D 17″ lcd that exhibits the following symptoms: when I first turn it on the backlight comes on (white screen) followed by slight line flickering then an all white screen that stays that way as long as signal is being sent to the screen. The OSD menu does not show up nor does anything else no matter what buttons I press on the front of the lcd. I opened the unit up and replaced a capacitor that I thought was bulged but looking closer at it once I took it out I think it might have been fine. Sure enough, the same symptoms occur with the new capacitor in.
Do you have any tips on what to look for next? I’m very new to this area but it interests me a lot.
Does a problem like this sound solvable at all or is the panel completely shot?
If all the output voltages are good then chances is very high the LCD panel have problem. I had replaced quite a number of them.
Hello Mr yong
19″ LCD SAMSUNG 920 NW shows display for a few seconds only.
Power led is on. What might be he cause of this.
Thank you very much.
It could be a bad backlight or faulty components in the inverter board. Sometimes dry joints also could cause it. Make sure also the output voltage are good.
I am in a process of reading the Manual LCD Monitor repair.I have a few
quire regarding Eprom programming as follows..
1)Is it necessary to have a setup for Eprom programming inhouse , I used to give it to a programmer ( out source) along with the TV model number. .There are also few PICs/Eproms available in the component shops with the firmware readily installed on it.Can you please let me know the equipments required for Eprom programming.
Normally i will save the program in my computer and use it to overwrite on suspected eeprom ic. I only save eeprom data of Monitor that have frequent corrupt problem. The equipment that i’m using is Pony prog and you can get one from http://www.lancos.com
2) How much will it cost for this type of setup i.e for monitor Eprom programming .
I bought it very long ago and do not know what is the latest price. You can check out the price from the website by emailing the owner.
3)What type of programmer should be selected i.e for eprom 24Cxx and other Eproms .
Pony prog have the function to program 24cxx
4)How can I recollect data from a faulty Eprom
There is no use of collecting faulty data as it can cause weird symptom in equipment if it is installed.
or where to look for
fresh data for Eprom programming.
Have to remove from a good working equipment (i.e Monitor, TV and etc.)
i am a new beginner of electronics and want to make some simple electronics circuits sir u give me e-mail address of any
thanx and regards
Sorry i do not have friend that make electronic circuit. They are good in electronic repair. I suggest that you visit forum by typing “electronic circuit design forum” and etc in google and hope you will find one.
Would yo0u kindly tell me what the identification of the pins on a FBT? Where will I find the primary of the FBT? I know what the transformer looks like but no idea where the primary pin is
and what the rest of the pins are for. Thank you very much.
Try this link:
1)when i want to find substitute for bjt transistors what parameters are important?(what parameters should i consider?)
The volt, the amp and wattage. The replacement should have the same or higher rating.
2)what is best books or softwares to finding substitute for electronic components?(with internal schematic of components)
It should be ECG REPLACEMENT GUIDE but they had stopped production. Now all have to depends on internet to get the components schematic.
I have got one non branded lcd tv(labelled sony on front) have pictures normal on left side and dark on right side.There are also two vertical lines on the right side.Picture attached. Could you give me an idea where the problem may lie.
From your description and the photo it seems like the LCD panel have problem. If all of the voltages are good from the smps then suspect a bad lcd panel.
i have monitor not so familiar.its name is epro from china.it is a flat crt type monitor.my problem is i cannot adjust the size and pincusion of it. can you help mo with this,,,
It could be a shorted modulation diode nearby the flyback area. If possible check all components located after the horizontal yoke coil.
its using atmel446 c2408a for its memory.and can you tell what i can use asa a replacement for this ic
EEPROM IC like 2408 need only the same number. You can use other brand but the part number have to be the same.
In a schematic, what does Vzz & Vdd are?
Sorry for the late reply. I have never come across VZZ before but i do come across of VDD which mean supply voltage. Please click on this link for more information.
please sir, i have a problem in LG model no. 21FU1RG-ST, when i on it,it will on but it just for a few seconds let say two seconds it will trip off again and the red light will be showing and when i press the button it will on and trip off just like that! But sir i notist that if the yoke wires are disconnected one dot will be showing on the screen but it will not trip off, but once the yoke is been reconnected back the screen will ful but trip off withing a few seconds, so sir i dont know what the problem is and i realy need your help to tell where to test .
Try from this link http://www.scribd.com/doc/2957819/TT204-Identifying-television-SMPS-problems to see if your problem locate in the smps or in the high voltage section. This will cut short your repairing time.
Hi, i have a car amplifier which doesn`t work properly. It has 38v on speaker terminals, i checked power and audio output transistors they are all fine. The only thing i could see was 2 burned resistors,but when i replaced them they burnt again. Any ideas where is the problem or where should i start? I attached a photo which resistors are burnt. Thnaks
When a resistor burnt ther must be a reason for it. I suggest that you test out all the components especially the semiconductor that is correspond to the resistor.
I am working in a comm testing department, repairing C-130 (aircraft) communication components.
Often I find my self troubled by testing motors, normaly they don’t have similar resistance value. Is
there any other way of testing motors, apart from checking the resistance?
Your help will be highly appreciated
I had a students that recommends me to check this equipment at:
i am sure if you go to chaina you will see and learn to many thing even new instrument
for fixing the lcd monitores your sepeciality . because chianes are very advance in the feild
of electronics they work seriously put time and money for more progress. i realy admire them to much
My friend told me that their technologies is much more advance than UK that’s why i need to check it out. Once i’m back i will post the photos and videos to my blog.
thank you so much of the adress of sanwa co they have office in
for leser meter
Please let me know too how much is the equipment.
i will have two problem first how to work with new set second if i found the laser head is broken where can i get a new one exactly same as broken one and how much this will cost me and my freinds.?
In fact this is the problem we are facing. If the head assembly is too high customer will not repair it since nowadays a new DVD is so cheap. The good thing about this tester at least it can help you to confirm that the laser is abd so that you will not waste time to test other circuit or components.
Your Name: Given
Message: How do I determine the value of resistors burned out on the output pin of a UC3842BN ic? The resistors is connected to the gate of a FQPF7N80C Mosfet. I cant get the schematic diagram aywhere. Its for a DSTV decoder PS301R power supply.
If it connect to the source of the FET then you can use a 0.22 ohm resistor. If it connect to the gate try 100 ohm but no guarantee.Sorry i do not have the schematic diagram.
I’ve one question pertaining television with brand: KONKA. The problem is that “Totally dead set”..
Upon checking the unit, the plyback was found & verified defective. After replacement of said “Plyback”
cause beleiving the plyback is the only problem, however, the unit still doesn’t “ON”.
Re-checking of the circuit has been made, so it found another defective part which is the horizontal
drive(part# D2102). My problem now is that I don’t find the same part to our local electronic stores.
Can you please advice where I can find the said part?
You inputs will be highly appreciated.
Try here http://www.bluestar-online.com/SearchResults.asp?Search=d2012&Search.x=0&Search.y=0