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Electronics Repair Questions/Answers and Testimonials- Part 78

By on May 12, 2011

hi jestine

my name is G.k  i have a 26 inch vizio tv that went out on me two months ago  i took it to the tv repair man and he charged me $200.00 to fix it the tv only just $300.00 new   well i paid it  then a friend told me about youtube and how i can fix my own tv   that’s when i saw your video and decided to learn about tv and laptop repair   i decided to buy your book on testing electronic components   after reading part of book i was impressed and will be buying more books in the  future.

Thank you

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

Thank you sir, this is very kind of you!

I have been reading your books with an excitement that i haven’t known in years.

I have two monitors that I am trying to repair.  (LG Flatron W2234S)
I am reading with earnst to get started on repairing them.

Thanks for such good work and making it available for us the public.

Jerry D

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

Thanks for your books they have helped a lot. I did not know anything
about electronic repair and with the help of your books I have been
able to repair more than a dozen Computer Monitors and TVs.
Thanks a lot!

burg

Pakistan

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

Dear sir,

Please explain me the reasons for overheating of HOT if it is in running condition and normal picture for 5 minutes. Is this caused due to EHT or not because EHT remains to check in a monitor.

Regards

Gopal

HI Gopal,

Not using original components, surrounding component have problem, a too high B+ voltage and a a leaky flyback.

Jestine

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

Hello jestine . I need your help today. I want to know the reason why line output transistor is alway damages even if i replace it with real one it will still destroy . Especially in the panasonics tv set . Pls enlight me on this situation . This problem make alot of looses for me in this job THANK YOU SIR.

HI Wakheel,

Please visit this link:

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

Jestine

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

Thanks a lot Jestine, now im doing a self studies based on your e-book and it’s big help for me to have a confident to test a electronic components. now im starting to invest some testers based on your e-book recommendation.

Once again i thank you very much and for power to you

 

Best Regards,

Samuel I

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

HI Hamzah,

Sekiranya HOT mempunyai 6 bacaan ertinya ia sudah rosak.

2)  Jika saya uji dengan Blue Ring Tester mulai dari bahagian anod (Diod B+ line) hingga ke collector HOT dapati semua lampu led akan menyala hingga ke warna hijau. adakah cara ini betul dan bermakna primary winding pada FBT itu baik.

Ya.

3) Jika saya uji dari bahagian cathode (diod B+ line) hingga ke collector HOT dapati semua lampu led akan padam, adakah ini cara yang betul untuk menguji primary winding FBT dan ini bermakna FBT itu rosak.

Tak semestinya rosak kerana sekiranya B+ line ataupun sekitar HOT collector circuit ada component shorted semua LED lampu pun boleh padam.

Jestine

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

HI Lee,

I’m also have problems with an samsung ls19mybebq/xsa monitor
I replaced all the electro’s in the secondary and the unit still has no power led light up.
I checked all the voltage’s & getting what is expected.
I have checked the inverter transformer & am getting sus reading on my Dick Smith Lopt tester.
Any advice would be appreciated

If you are getting voltages even in the mainboard then the MCU have problem because the power LED signal is coming from the MCU.

Jestine

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

En. Jestine

setelah saya menggantikan HOT dan satu capasitor bernilai 104J630V tv itu pulih seperti biasa.. terima kasih.

satu lagi pertanyaan:-

kenapa ada transistor mempunyai 2 bacaan (low ohm) dan ada yang 4 bacaan (low ohm). contoh pada transistor C4927 mempunyai 4 bacaan dan D1403 mempunyai 2 bacaan diharap sudi menjawabnya. saya telah cari jawapannya di internet tapi tidak jumpa.. terima kasih..

HI Hamzah,

4 bacaan kerana ada damper diode kat dalam HOT. Tahniah atas kejayaan kamu.

Jestine

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

HI Bobby,

As I mentioned, I am leaning how to repair monitors as a retirement hobby to stay busy more or less… I have 15 years experience in electronic /repairing but not commercially..

Noted.

The Acer P191W is a learning project so not really that concerned about making repairs per se..I can not locate a service manual for it.

If the repair tech in ACER did not upload the schematic then we will not find it.

The main challenge is servicing these things I think is in setting the boards up for testing so as to be able to see what is happening… I use a Sencore pwr transformer, Sencore analyzer, Fluke meter and a Dick Smith ESR for testing..

Noted.

 The main concerns is that it will shut down after 45 min or so of excellent operation as evident by the blue light not being on and no amber..Pressing the pwr button again, the monitor would pwr back on and be ok for another 30~45 min..  ??I am wondering that this is not a problem and may be going into hibernating mode rather than shut down???It was discovered that one other symptom is that the OS Display control buttons are inoperative ( not working) when pressed while the unit  powered up and  video is being displayed ( blue light on,pwr on).Testing the inputs into the keyboard shows low voltages except for power,led and auto.. SEE BELOW

If all the voltages check to be good even after shutdown I’m afraid the MCU have problem. You can also try to use Freezer (coolant) to spray on the MCU or any IC on the mainboard to see if it will work longer or not.

Following guide lines in the excellent guide lines in your E book, the voltages in the power/inverter board checked out ok as evident by the blue power light being on, and a display of test pattern front the Sencore monitor analyzer…

 I do not know what the voltages should be but some key voltages were 12 V, 6V 15 V and 1kv (to backlights off of 2 transformers…(these voltages were not exact but rounded off).  May go back and remeasure to be more since the ripple in the main filter cap may be causing the voltages to be some what lower..(see below)*

The E caps visually were ok, and checked good with  Dick Smith ESR meter..

Main Fly back ranged with 4 rings.. HV transformer for back lights (2) out put 1KV  rang 22x (good!)..

They are good.

 

The FET transistors driving the HV feel almost too hot even on the heat sink..

On the main supply board,  the FETs mounted on the heat sink are the only components that feel over heated.. (almost too hot to touch).

It can’t be too hot to be touched. Try use freezer on this FET and if the set will work for longer hour then this might be the culprit.

*The main Filter cap (100uf 450v) has 145v across it. (NOTE: IT IS SHOWING 15V~17V PEAK TO PEAK (ripple??).  This is the only abnormal measurement I can find as I think  15~17v Peak to peak is way too high in a filtering circuit/// What is your opinion..?  I do not know  what the specs are but it would seem to me this ripple would affect down stream measurements somewhat but would it cause the shut down..Unfortunately, I no longer have my Sencore scope and do not know the nature of the P/P ripple..I can only measure it using the analyzer..I am currently research a source for this cap..There are no electronic supply parts store in my area…

The most important is the output voltages. It has to be good and stable. From your description above about the voltages that you got  it seems that the power supply is working fine.

On the mother/control board, what the books calls the scalar IC (larger square ic (RTD2533VH, 76248Q1)  is almost too hot to touch also..It cools down quickly when it shuts down…The other components are  barely warm..E caps no bulging and check good on ESR meter..

Get the coolant to spray on that IC as well.

Pressing the keys on the key pad for the OS does not cause the OSD to pop up..The only one operational is the pwr on/off….Voltages into the key pad of the various functions are really low ranging from 3v for auto to 0. The lED voltage is 2.86 and .86v {amber and blue).3 v pwr.. The electrolytic on the mother board checked out ok via ESR..

I know this is a lot of data, but the conclusion is assuming the ripple noted on the main filter cap is not causing problems, the Scalar IC is trying to fail and is not outputting control signals to the OSD or the EPROM is corrupted…

What is your opinion..Is the main cap causing problems??

If the output voltages is stable and good then it is not the main cap.

Would you suggest a supplier for a E cap 450v 100uf   (35mmx17mm or so)?  the one I have is made by SU’ scon, not very reputable company from what I gather..

 Try this link:

http://my.mouser.com/Search/Refine.aspx?Keyword=450volt+100uf

If the cap is slightly bigger i guess you may need to modify the board space.

Thank you so much for your E book.  I have several of them that I have either purchased or down loaded…

Thanks for the support!

Jestine

http://www.JestineYong.com

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

Hi Boling,

I hope you are doing well there.

I’m fine thank you.

These days I just begin to learn to repair laptops but unfortunately the free service manual I got from the internet don’t have any schematic diagram, it only has block diagram and troubleshooting chart. Do you know where I can get the one with schematic diagram?

Free one hard to get. Have you try http://www.eserviceinfo.com ? or you can try the pay diagram:

http://notebookschematic.com/

 

To get more work on monitor repair, I plan to buy some dead CRT monitor from a factory which almost always being turned on and they say all the monitors became dead only after one or two years. The advantage I see is the monitors had not been repaired by anyone. Do you see any risk from buying these kind of monitors?

I don’t see there is much risk in this thus you can try it out.

What section suffers the most if the monitor runs continuously?

It depends on design but mostly is the power section with bad filter caps and dry joints in the board. If the monitor are using 3rd graded tube then the tube can have problem

Some of the tube even has shadow of the display they used to show ( only one sort of display along the working service time of the monitor ). Could this kind of picture tube still display normally?

If the tube is from low quality and have shadow then most probably the tube have problem.

How about the LCD monitor, do they have the same problem if the display is almost the same anytime?

No-LCD panel do not have this kind of problem.

Once when I repair a monitor, after replacing the HOT with C5411 ( I forgot the original part number, but should be from the C5XXX family), the temperature of the HOT reached 70 deg C after about 15 minutes, but the ampere drawn didn’t go up. Do you think this monitor will last long? What is the highest temperature of HOT do you ever notice when monitor is on, but you know the monitor is working well and will last long?

Usually i did not take the temperature because generally if the HOT temperature begin to rise you could see the amp draw will rise too. if it stagnant at 70 deg C then it should be ok and make sure it is not too hot to be touched. But you need to test on all resolution. Different resolution will cause different B+ voltage apply to the Flyback primary winding and HOT.

In the time to come could I ask you some laptop problem, since the laptop video repair by Steve only cover trivial issues; if he claims it was motherboard problem then nothing can be done whereas I want to do is the motherboard repair.

Actually Steve is right about the motherboard repair unless you can source the part and have the BGA rework machine. When i was in China 2 years ago, i could see that they have all the parts and tools on their repair bench that’s why they could repair laptop at super fast speed. Yes you can ask about the laptop question, if i know i will answer you. 

Do you often do LCD TV and LCD projector repair?

I rarely repair both equipment because my company is mainly dealing with the courses and computer related repair. The other day i opened up my new 24″ lcd toshiba TV and found that it was almost exactly the same as a normal LCD Monitor except that it has the tuner. The bigger size LCD TV 32″ and above have a more complicated circuit. All the boards are generally bigger and have much more components and more backlight. Repairing LCD TV and LCD Monitor is generally the same. Find out the critical test points and if you could source for the parts you are already in business.
Jestine

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

hi SIr,
it has been a while since i last post a question. Hope you are doing great!
Regarding your december repair newsletter on LCD TV. One of the faults you found out is that the MOSFET is tested good off board
but failed when under full operating voltage.
My question is, how do you test the MOSFET under full operating voltage? Any ways to test it? Thanks

Regards,
Phua

HI Phua,

The best test equipment is actually the tv itself because it pumps in all the require voltages/signals to the component under test. In other words there is no way to test other than to run it on its own circuit with power on.

Jestine

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

How are you? Am fine hope you to. I have a proble with a tv the problem is that when switched on it returns back to standby mode i’ve tested the passive components but nothing is happening what might be the problem please explain to me the causes of this, i also have problem with another tv when powered power enters in the circuit i have tried to measure voltages the 110,12,18 they are present but the tv is not switching please explain me what causes this. And please i have problem in measuring ceramic and mica capacitor how can i know they are bad using a digital meter thanks am waiting to hear from you God bless you

HI Elahuya,

I’m fine thank you. Have you check the dc supply to the main power supply power ic? Certain power supply use optoisolator ic and the cpu will send a signal to the optoisolator ic in order to fully turn on the main power supply. If there is a missing signal or the cpu is bad then check the optoisolator ic area or replace the cpu.You need a digital capacitance meter to test on the non polar capacitors.

Jestine

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

HI Boling,

Yes, I’ll try it out. The dead monitors are AOC brand, should not have big problem.

Noted.

I feel 60 deg above is too hot to touch already. The problem is my cheap Clamp meter can only show 0.2 A, so I don’t know whether it was 0.21 or 0.29 A.

May be you need  get one that can support higher amp draw. Common amp draw for a 14 to 17″ crt monitor is about 0.2 to 0.4 amp depending on model.

I know that we could buy even the north or south bridge BGA IC from China for the notebook, but I don’t have the BGA rework station at the moment and don’t have the budget. Do you already have one and have tried to replace north or south bridge? What is the model of yours? How much is it? Is it IR type necessary in this field of repair?

I don’t have one at this moment but will buy it in the future.

One must have tool to repair LCD TV is the HR diemen backlight tester which can test backlight to 42″ size if I am not wrong, but they don’t sell it at this moment, do you know other source for this?

I’ve been to ebay site and found few and you can check it out. Make sure the spec that can check bigger tv.

The china version is only capable to test up to 600mm. It’s good to buy which can test longer one. It’s harder to find China supplier for LCD TV parts than the monitor parts, also they sell mainly from their own brands.


Sometime i wish that my side here have a company that sell all the lcd tv/monitor/laptop/plasma related tools and parts but at current moment is none. You understand mandarin thus you can log in to taobao.com because i was told that it has many things to sell and also not all seller in the website/forum are genuine.

Newer LG 17″CRT monitor use MD2310FX  HOT which has V EBO= 9V, while the C5411 is only 5V. Do you think this type of HOT is still able to be replaced with C5411? Please see the attachment.

I have not use that number as replacement before thus i suggest that you try it out and if it is hot then you know it can’t be used.

Jestine

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

Sir,
I am nihar , i repairing a lcd tv NIKAI
Model no- NTV2401 LCDFHD its SMPS & inverter bord adjust. Smps ic position IC201 , 8 pin smd ic (green mode controller with high-voltage start up circuit) the ic number is LD7575PS . Smps output socket connection is
12V 12V
GND 12V
GND GND
5V    5V
GND SBTY
ADJ  ON/OFF
I dont found this ic in my country big market kolkata chadni . How i get the ic  , please help me sir .

Yours faithfully
Nihar/india

HI Nihar,

 

Try this link:

http://www.utsource.net/LD7575PS.html

Jestine

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

Hi Jestine, recently i adquired from your web “Testing Components”, I found it very nice, good and very well explained. Following your suggestions, I orderer an analog multimeter from ebay. But I got surprised about it because it has no 10K Ohms. scale. From lower: 1, 10, 100, 1K it jumps to 100K, voltage on low scales is around 3V, and voltage on 100K is about 1V. Do you think I can use this multimeter, or would you recommend to look for a better one? Thanks in advance. Pedro Motilla from Valencia, Spain.

HI Pedro,

Thanks for the support on my ebook. In fact you really need a x10 k ohm multimeter because x100k is not good enough to check on semiconductor especially the power FET.

Jestine
http://www.JestineYong.com

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

Hello Jestine, How are you.?.

Fine thank you.

Sir,

Original SMPT which I  am suspecting was S 80A S774-2-V 1G HI POT TPV-B1 0645 OK

Now I got replacement for the same as 80A S774-2-N G YUVA0544 HIPOT B-2 OK.

Sir will you please suggest, can I replace the same for my above said monitor. if not please suggest some compatible

You can try it out. Usually there will be no replacement for power transformer because all are design to be unique. Make sure the primary and the secondary winding have the same inductance value as the original one.

Sir Please explain  meaning of this  Model No. 80A S774-2-V 1G HI POT TPV-B1 0645 OK details for me understand this SMPT Features..

Sorry no info on this because only the manufacturer of the transformer have the details of this part number. By the way HI POT means Hi Potential.

Jesitne

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

Hi Jestine,

This is a Hitachi CRT 15″ monitor, quite old one. The problem was blank & little bit grey color display and was found that the vertical IC had cracked.

After the vertical IC had been replaced and because I had pulled out the anode cap to make clean the main board and then replaced back the anode cap and I could assure the anode cap was put back appropriately. But now, every time this monitor is switched on there is noise from the picture tube anode cap, like the noise when you frying omelette, and this noise make the owner feel uneasy and brought back this set to me. Actually the image display is perfect.

Do you know how to eliminate this noise? This is the second time I repair CRT monitor and got this kind of annoying noise.

Thanks,
Boling

HI Boling,

If the high voltage check to be good then clean the picture anode surrounding area. You can clean it with dry cloth. Please update me on this.

Jestine

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

HI Boling,

 

I have cleaned the anode cap surrounding area, and there is no grease. & dirt at all. Please see the photo.

 

This monitor is actually also using junk flyback as blur buster, but the junk flyback has no ferrite core, is this OK? Please see the attached photo.

Yes it is ok but it has to be properly connected and secured.

 

Since cleaning didn’t help, I had also tried to resolder the two anode cable from both the flybacks and still the noise is there but smaller now I think. Resoldering this was a hard job since the cap hole is only one. 

I also attach the image display of this monitor, it is still really good one. 

Is there any other method to eliminate the noise? Could it be the pins of the anode cup are not good enough? See also the anode cap pins photo, they are different from the usual one.

Yes it could be that also. I suggest that you use another junk flyback and test it out and make sure the joints between the two high voltage cable is not exposed and properly solder under the anode cap.

Jestine

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

Thanks  for  great   information;   a  couple of  question  ..      WHICH  make  of  electolitique  condenser is  the  best  for   repair use,  good ( esr) subject,    In  iil  sonic  moitor  I  find  the   self ( choke) near to the   mosfet and  the   regulator  is  burnt,    ALL  the  coils  are  burnt,,  having  changed the   two   CI’s   and  rewound  the  choke,  the  monitor  lights  up,,,  BUT  the  choke   starts to  burn  again,,.  this  choke  is  wound  on a  ferite  core..

the   two  Ci’s  are  IRF 7313    and  RT 9203,     from  what I  can  see  from  the  net  this  problem  is  WELL  known  to all   speacilists,   and  NOBODY  can  suggest a  cure  to  this  evasive  problem,,   to us  anyway,  BUT  maybe  you  have an  idea  on  this  subject…

Monitor  ref  is   II M17F    IIsonic   Voila   Thanks  for  any  suggestions  you  may  have to  help  us..

Haydon

HM Services  electronic  France

Hi Haydon,
I assume that the choke is the B+ coil. If it burnt again then there could be few factors:
The choke itself did not wound properly
The load or the flybck transformer have problem
the surrounding components have problem.

Jestine
http://www.JestineYong.com

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

Hello sir,

 

I have two metalurgical microscopes with model number S41959 fitted with two halogen lamps rated at 30W.

Recently, the halogen are not working and I already checked and confirmed that the power supply unit is defected. The problem is the board is seal by hard epoxy @ gam batu black color. It seem like the company that design the board would not allow others to fix it. It is very difficult to open it to see the circuit.

So if you had same experience or had face the same problem, i hope you can share with or suggested a solution.

Thank you.

Best regards,

Aswadi

USM

HI Aswdi,

Try visit this link and see the comment:

https://www.jestineyong.com/?p=3099

jestine

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

Justine,
I have a question. I recently purchased an ESR meter which also measures capacitance while in circuit. On many occasions I get a reading of a leaky cap with low resistance. Once I take the cap out it seems to read fine capacitance wise. The meter I have is an Atlas Model ESR70. Not how to gauge this reading.
Gene.

HI Gene,

Actually it is normal for all ESR meter to check the leaky cap as normal. The reason for it is because the leak is not too severe till it could affect the reading of the cap ESR. As a rule of thumb, direct replace any cap that you found to have oil leakage.

Jestine

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

HI Ng,

In addition, I had a question in regard to the CRT monitor, it became blur on the graphic, do you have any idea what caused the problem?

If it can’t be adjusted from the knob of the flyback then it is either flyback or the tube have problem. If it slowly become blur then suspect flyback.

Jestine

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

HI Boling,

To my surprise actually the noise is not lighter because when I try to switch on at night the noise is still very noticeable and sometimes it makes a short-burst noise and this really scared me but don’t know where was the exact location. About the joint between the two anode cable should be fine already ( I spent about 2.5 hours only making that perfect joint ) and making sure the junk flyback properly placed beside the deflection yoke. But the owner said before the problem appeared ( vertical IC cracked ), he heard no noise at all, this is very unbelievable. Could it be some damp air trapped under the anode cap causing this, as this monitor had been used for many years without pulling out the anode cap?

Never heard of damp air that is trap under the anode before. May be you can try without putting the additional flyback and replace it with another another cap.

I’d rather give up doing any further repair on this, since the second AOC monitor I bought had arrirved, you could see in the photo. From your experience in repairing CRT monitor, what is the brand of the best picture tube ( have the best display image )?

Hitachi but again it depends on the crt dot pitch. The smaller the dot pitch the better is the quality of the picture.

It is interesting to find that those AOC monitors using different picture tube, some are Chunghwa and others are LG-Philips. The latter seems have better image quality.

Chung hwa is not a good tube.

Another question is about the IRF3205 Power Mosfet used in a UPS. I got two version of this, as you could see in the photo. One is with blur metal case and the other is with bright metal case. Which one do you prefer to use?

Actually both also can be used. When i purchase parts from my supplier sometimes i do encounter this kind of problem but at the end both still can be used.

Jestine

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

 Hie Sir.

To start with your book is the best book i ever read in  electronics, you make electronics seems so easy, am so happy. i managed to repair my first componentS a dvd player and a laptop power pack.

 Thanks Simba from Zimbabwe

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

Now I need to go over all of your fine content and links to learn of all of it’s various uses, not only for caps, but also for finding shorts.  I wish I would have had one for many years doing pro-audio.  The most annoying and time consuming thing was trying to find a shorted op-amp when there were 20 of them all on the same +- 15 volt rails and the manufacturers lack of forsight to put a resistor previous to each.  I came up with checking each of their temperatures, using a dab of wax on each to see which melted first, cutting traces, using signal injectors to see which one bled into the rail and etc.  I enjoy your newsletters and have picked up many useful tips, thanks!  You are a boon to our trade.  Keep up the good work.  Next purchase, blue ring tester.

 

Thanks again,

Darren

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

Hi Jestine Yong,
I remember asking you if you know what needs to be done to fix an LCD
Philips monitor that the display comes on then for a split of a second
off. I have replaced all the bulged capacitors and even those that are
not bulged on the Inverter board but still the LCD Philips monitor is
doing the same thing, any ideas? I remember the earlier communication
you advised me to replace all the capacitors on the inverter board
which I did but still not sorting out the problem hence coming back to
you for more advice as you are more experienced on that basing on the
PDF books of LCD monitor repairs that I bought from you.
I need your expertise on this.
Thanks for your usual help.
Goodson

HI Goodson,

If there is no dry joints in the high voltage transformer and the supply voltage to inverter ic is normal then one of the backlight already have problem. You may need a backlight tester or compare it with a known good backlight.

Jestine
http://www.JestineYong.com

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

HI Aboagye,

I have gone through your E-BOOK which I bought a few weeks ago and
it’s just wonderful.
This is all I have been looking for.
I will start consulting you for further help as stated as part of the
bonus when I start the the actual practical work to help realise my
dream

Thanks for the support!

For the mean time I want you to please help me with this question.

I have two 12V , 4.5ah battery in my UPS which has become week and
cannot sustained power for even 10s when there is light out.
Please can I replace these two battery with only one 12V battery and
what should be the ampere since I cannot find the same battery to
replace it.

 Although i have not tested this kind of connection using one battery, the best is to replace with the original spec to avoid any problem. The 12 volt 4.5 is a common spec and it should be easily available from the marker. In fact you can use a slightly lower ah.

Jestine
http://www.JestineYong.com

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

Hi Dear Jestine Yong

would you please tel me how an UJT can be cheked by a multimeter please?

Thanks for your prompt reply. You are a great help to anyone who wants to learn electronics.

Hi Ben,

Try this link:

http://www.sentex.net/~mec1995/gadgets/ujttest.htm

Jestine

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

HI Boy,

good day to you and thanks a lot Mr.Yong for the May repair newsletter.

You are welcome.

as usual i’m soliciting your help with this problem.as much as possible i dont like to disturb you as long as i can manage to fix any problem but without sophisticated tools with matching knowledge to use this special tools if there is, its complicated to conclude what really went wrong.

i’ve tried a lot of passive and active checking but i cannot find any bad component in this tv circuit.the color on picture is not normal.sometimes the red is too strong or the blue color.i have checked rgb voltages on crt pcb-kr=186v,kg=186v but kb shows alternate 106v-high voltage.at first i doubt its electrolytic capacitor that is bad but i checked all electolytic,ceramic caps but all are ok.if i disconnect the red output from pin #19 of jungle ic, kb will show a steady 186v but there will be no raster.i replaced the jungle ic but with the same result.

i’ve also checked the circuit thru series bulb without connecting to picture tube and at this time kr,kg and kb shows steady 186v.ive checked the circuit’s component again and again but still i have not found any bad component.is my conclusion that the crt is bad right or is there any other cause for this symptom?please advice.

thanks a lot and GOD BLESS!

It can be caused by corrupted data. If you could access the service mode of the tv then there is chances this tv color can be adjusted.

Jestine

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

hi,

i have a d-link network switch that i have discharged its capacitor that i needed to test. what i did is short the capacitors terminal and as expected, it discharged its stored electricity.
after some testing, i place the power supply board to where it should be. when i put power on the switch, IC A6351 blown. it was working before.

does discharging of capacitor by shorting its terminals can damage parts on power supply board?

Francis

HI Francis,

If you discharge a cap with a metal then yes there is a chance of shorting other components. if you discharge it using a resistor then it should be fine.

Jestine

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

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2 Comments

  1. sallehuddin z

    May 12, 2011 at 9:39 pm

    Dear Justine,
    I not sure this is correct place to get some advice from u.

    I hav 2 set LCD monitor HP1825 & samsung 2033sw and they having the same problem, hopefully u could give some advice on this matter.

    The initial ON, the display was perfect, but after 10 sec. the display gone blank, what could be the faulty component..?

    For your info. on the HT board I do place the testpen on the ht trasfomer and the testpen light up, to me this ia an indication the ht was there. what do u think...thanks for your time.
    saz
    penang.

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  2. admin

    May 13, 2011 at 7:31 am

    HI Saz,
    After shutdown is there still supply voltage at the vcc pin of inverter ic?

    Jestine

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