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Repairing BenQ 17″ LCD Monitor
By Jestine Yong on January 31, 2008
I came across a common fault problem in BenQ 17″ LCD Monitor. The problem is have power but no display. Once you has opened the LCD cover, check the pico fuse for open circuit (very common), the push pull transistors C5707 for short circuit and the Buck royer circuit p-channel fet FQU11P06 also for short circuit too. For your information, if you can’t get the FQU11p06 you can always use FU9024N as a replacement. Resolder all the high voltage transformer pins and replace the components above and I’m sure you will bring back the life of this BenQ 17″ LCD Monitor.
You may go to this fairchild semiconductor website to download the spec of the FQU11P06 P-channel FET.
http://www.fairchildsemi.com/ds/FQ/FQU11P06.pdf
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Ishwor maharjan
November 28, 2011 at 7:24 am
BeneQ 17" lcd monitor- led light on bath no display what problem place queckly our answer.
admin
November 30, 2011 at 3:08 am
HI Oxide,
Yes it can be that problem. You can use other brand of 1000uf 16 volt ecap.
Jestine
Eric from Kansas USA
December 6, 2013 at 7:59 am
Mr Jestine
Hello! I have purchase a couple of your books. Love them. I have a question. Where can I purchase a good extra small soldering gun I can only find those hobby ones and the tip and frame are just to big. I end up heating up something else and breaking it loose.
Thanks for your help and teachings!!
Eric
From Kansas
Jestine Yong
December 6, 2013 at 10:23 am
Hi Eric,
You can try from the below link:
http://www.howardelectronics.com/
In your case I suggest that you get the temperature controlled solder gun as you can adjust the temperature to suit your soldering work.
By the way thanks for the support on my ebooks.
Jestine
Oxize
November 30, 2011 at 6:49 pm
Thanks. I found some Caps at LCDAlternatives which sells BenQ caps packages.
Only need time to solder them. In the meantime when i opened lcd i resoldered the slightly bulged caps. At this moment the monitor doesnt goes blank. Thats great, but i still need to replace those 2 bulged caps right? If i dont it can damage more components?
Anyway, thanks for your great help Jestine!
Snowdog
December 1, 2011 at 12:55 am
I have Benq monitor T201WA, and one of the buttons don't work...
Sometimes it works, but most of the time it doesn't...
Is the problem corrupted EEPROM data? Because it's not completely "dead"
What can I do about it?
admin
December 1, 2011 at 3:31 am
Hi Ishwor,
Have you check the supply to the inverter ic? What is the color of the power led?
Jestine
admin
December 1, 2011 at 3:33 am
HI Snowdog,
Try directly replace the button and if it is still the same then the problem could be corrupted eeprom or a bad MCU.
Jestine
admin
December 1, 2011 at 3:34 am
HI Oxize,
Yes you need to replace the two cap first and retest.
jestine
Oxize
December 7, 2011 at 5:12 pm
Hi Jestine,
I replaced the Caps last saturday. Today, the monitor went blank again after 10min. Tried on/of few times. Got screen for few secs, then again blank.
Any other clues?
admin
December 11, 2011 at 8:24 am
Hi Oxide,
If there is no dry joints in the high voltage transformer section then it could be one of the backlight have problem. A fail backlight will cause the display to shutdown in few seconds.
Jestine
Mhel
December 11, 2011 at 4:15 pm
Hi Mr. Jestine Yong
Gud day, I am a newbee about LCD repair, I started repairing last 3 months. I have fixed most of them when only the secondary capacitor is the problem. Right now I'm facing lots of problem regarding white screen display ang most of them are those LCD's on 12v supply. May I ask you if how can I measure smd type capacitor on the board, How would I know if they are faulty or not. I am using a analog multimeter here for testing components but for smd type capacitor, how can i measure it without spending for those expensive tools.
Hope you can help me, Thanks in advanced
Tony
December 11, 2011 at 9:48 pm
Hi Jestine
I've been learning a lot about electronics this evening, much of it on your excellent site. I have a Dell E173FPb 17" screen that will show the computer desktop for a second then go black. If I switch it off for a few seconds and switch it on again it will do the same, over and over. I have disassembled the screen and two parts look like there has been a lot of heat as the board is discoloured on both sides. Both could be transistors from what I have learnt, their numbers are K-438 C945 P and FU9024N I*R513A 5A 6F. I tried to test them with a digital multimeter using several online guides but I don't know what I found out!
Is the fault likely to be down to one or both of these parts? There appears to be soot under the C945 P unit. No other parts look damaged or distorted. The board is made by Benq. This isn't the same as the usual E173FPb fault.
Many thanks
Tony
admin
December 12, 2011 at 3:57 am
HI Mhel,
SMD cap can't be checked on board (except SMD electrolytic cap that can be checked with ESR meter)and it needs to be removed out from the board. Test the cap using digital capacitance meter to check on the value and then use analog meter set to x 10k to check for short circuit.
Jestine
admin
December 12, 2011 at 9:47 am
Hi Tony,
It can be those transistors problem, dry joints in the high voltage transformer, bad e-caps or even one of the backlight have problem. I suggest that you compare the transistors with a good one and if there is a different in ohms value then you may need to replace it.
Jestine
Zaharia Constantin
December 29, 2011 at 7:16 pm
hi, i have a benq FP731 with a strange problem,
when is power on, the panel is white and nothing more, after a few second go to standby, the led is amber-orange, abut when i have the signal stay green.
any idea way the panel is white and what is the problem?
admin
December 30, 2011 at 2:53 pm
HI Zaharia,
Try check if the filter capacitor are ok. If all the voltages to the mainboard are normal then suspect the lcd panel have problem.
Jestine
Md. Shahjahan
January 4, 2012 at 1:28 pm
Dear Mr. Jestine Yong
How do we confirm that the push pull transistors C5707 and p-channel fet FQU11P06 short circuit.
Md. Shahjahan
Bangladesh
Electronic Repairer
admin
January 5, 2012 at 8:08 pm
HI Shahjahan,
You can use your multimeter to check or to compare the reading with a good one.
Jestine
jayarajankb
January 7, 2012 at 2:48 am
Wish YOU very happy new year.
thanks for your help to the technicians I admire your generousity.
thanks a lot
jayarajankb
MichaelS
February 17, 2012 at 5:24 pm
Useful web page and advice, congratulations and thanks. Question: BENQ FP71V monitor, L0Y02.A10 power board, a Q7C4 variant (usual one is .A02). Have circuit diagram for A02 version, similar but not identical (A10 has 2+1, not 4+1, transformers; most of board has same component codes like IC701). Symptom already described here: powers down intermittently with pilot light off. If cold, will usually work correctly for a few minutes or hours; if warm will probably power up not at all, or briefly. No capacitor bulged or leaking gunge, all e-ESRs (except 1uF) below 2 ohms. For these problems I think you have said if voltages normal, probably logic board; otherwise likely C, R, or joint on power board. Additional visual symptom: 3-pin 3.3V regulator, IC701, LD1117, powered from 5V line, is soldered flat to bottom of PCB. The top of the board above IC701 is very heat-blackened (not totally charred, and no metal traces there, partial short not likely). Is this normal for these boards, or does it pin down the diagnosis further? By the way, board doesn't seem to have 2SC5707 anywhere (nothing looking like any 15W transistor, just 1 big heatsinked FET, 2 heatsinked diodes). Lots of tiny 2mm SM transistors on bottom of PCB near transformers. Thanks
MichaelS
February 17, 2012 at 5:35 pm
(Following question on BENQ Q7C4) A question I haven't seen discussed: there are a lot of monitor circuit boards, mostly described as used, on sale on eBay, mostly from sellers in China. Does anybody have any information (statistics) on whether these boards are tested and good, untested but usually good, or likely to be bad? Best wishes
Mhel
March 7, 2012 at 1:32 pm
Hi Mr. Yong
I have here a 22 inches lcd monitor and the problem is the inverter board part, i was wondering if can i used a inverter board that came from a 17 inches lcd monitor w/ the same output jack?
Hope you can help me regarding to this prolem.
Thanks in advance and more power
Mhel
Jestine Yong
March 8, 2012 at 2:43 am
Hi Mhel,
I have not try that. The only problem i could see is the 17" inverter may not be able to supply higher ac voltage to the 22" lamp thus causing the display to go slightly dim. But then again you can try to increase the brightness setting. Just try and see how it go.
Jestine
Ronald D Hiltz
March 19, 2012 at 11:06 am
Hi! Love your site.
I have two Benq "Q22W6" LCD's that have been passed over to me and the inverters are 4H.03V02.A02 seem to have the same fault. On and flash Benq logo and black screen. Indicator light on, opening up the screen and cycling on off switch a faint buzz and the faint smell of ozone from each inverter! I have changed out the CAP's and the MOSF's and the same problems???
Has any one had this problem? First visual of all CAP's looked very good changing them made no difference. Has any one solved this problem?
Jestine Yong
March 20, 2012 at 8:48 am
HI Ronald,
If the high voltage transformer resistance are good (you can compare the transformer reading) then suspect one of the backlights have problem.
Jestine
Heldebrando Hollon Jr.
March 25, 2012 at 6:09 am
Hi Jestine,
I have a problem in the BENQ Q753 LCD, it is have power and when I connect it to the Desktop. The LED Light is go to Green it means work fine but only display is not coming. I open the LCD to check the board and the connection of backlight. Then i found the the CN751 and CN753 is have a mark of burned. May I know what is the cause of the problem for not being display. It's backlight problem or only in the terminal CN751 and CN753. It can solve the problem if it was replaced the defective part with a new one.
Thank you.
Heldebrando
Jestine Yong
March 27, 2012 at 10:36 pm
HI Heldebrande,
If no display with green power led this could mean the inverter is not running. Try shine the lcd sceen with bright torch light to see if there is any faint picture. If you could see those faint picture this mean the supply is not reaching the inverter ic. Try check if the supply voltage present at the VCC pin of the inverter ic-it could be the pico fuse has an open circuit.
Jestine
Sagres
April 11, 2012 at 3:33 am
Hi Jestine,
I have a 10yrs old BENQ FP747 (17") monitor and was working perfectly until 2 months ago,now all I can get is a black screen and a flashing intermittent light(near monitor power button) and is orange when PC its turned off and flash green when is turned on,weird part is yet to come, time to time, randomly , I can get the monitor working as it should for hours or even days its all good while pc is on, as long as I won't turn the monitor off or restart again(weird isnt it?) then it turn black screen and all those flashy orange and green lights turn up again unless I randomly power on and it works fine somehow again...so my question is, how can this be possible? I can't keep my pc on forever 🙂 wich components should I replace for this monitor model?
Thanks in advance and nice work you have been done for far.
Jestine Yong
April 11, 2012 at 8:51 am
HI Sagress,
It seems like the problem could be in the filer cap. It could have bulged. If those capacitors are good then suspect the voltage regulator IC 1.8 v or the 2.5 v have problem.
Jestine
Sagres
April 11, 2012 at 11:28 pm
hello again Jestine,
Do you have any Benq FP747 circuit boards diagram or at least a diagram that very similar to this model that you could email me? Ive tryed allover internet but I couldn't find it so far and BenQ can't provide me those anymore not even a service manual because it's too old,if you found or know any free source ,please send me,i would be gladly thankfull.
Jestine Yong
April 12, 2012 at 8:42 am
Hi Sagres,
Sorry I do not have the diagram. Have you check from eserviceinfo.com
Jestine
michael chong
April 30, 2012 at 11:01 am
hi..mr yong,i am michael chong from sabah malaysia...i just want to ask i have dell 19 " lcd,model : SE198wfpf...the problem is the display will auto blank after 3 second like that...i have open inside and look for the capacitor and it look good..but i have replace all the capacitor to test..it still the same problem,which part is faulty normally???
Jestine Yong
April 30, 2012 at 9:01 pm
Hi Michael,
It could be due to bad high voltage transformer or one of the backlights have problem.
Jestine
michael chong
April 30, 2012 at 9:38 pm
ic..then i need to change transformer or backlight to test???if i change backlight...i change other backlight from 17" lcd backlight to test,can????
Jestine Yong
April 30, 2012 at 9:42 pm
Hi Michael,
Yes you can try that if you do not have a 19" backlight. In certain monitor the display will shutdown if you are using different backlight but to some it can work. If you have the 19" backlight then it will be good because you can 100% confirm that the backlights are good and the problem in the high voltage transformer.
Jestine
Mihir
May 18, 2012 at 1:22 am
hi jestine
today i have faced problem with my lcd monitor
it shows one red line on the left on the monitor and some tomes it goes down
and again i tried to on.off the monitor again i found the same what could the problem cause for this
regards
Mihir Patel
Jestine Yong
May 19, 2012 at 5:25 am
Hi Mihir,
Usually lines are due to bad LCD panel. What do you mean by sometimes it goes down?
Jestine
Adrian S.
May 21, 2012 at 7:02 am
Hello Mr Yong,
I have a BENQ FP92E Model Q9C5. This monitor (19") has been used not much at all; one day I saw the LED is not amber in standby and I pressed on off button, nothing happened, then I pulled out the cord from the mains. Then I put it back, LED no lit on button press, no clicks, I removed the cover and the other shield metal cover. On the PCB everyhing seem to be ok, electrolythic capacitors looks ok (flat heads). Fuse measured OK. Have you any idea? Thank you in advance for your help.
Jestine Yong
May 21, 2012 at 8:56 am
HI Adrian,
You need to make sure the output voltages from the SMPS and the voltage regulator ICs are good and stable. If it is not good then it will have problem.
Jestine
Mihir
May 23, 2012 at 7:10 am
hi jestine
I mean lcd is not working properly sometimes it don't start i don't know why
can you pls help me
Thanks
Jestine Yong
May 27, 2012 at 4:14 am
Hi mihir,
I suggest that you check the filter capacitor and if there is any dry joints in the circuit board because you mentioned that sometimes it can't be started.
Jestine
сергей
June 10, 2012 at 8:50 am
не могу найти схему монитора BenQ Q9C5 FP92E.пришлите если можете.
Jestine Yong
June 12, 2012 at 7:52 am
Sorry I do not keep schematic diagram. Try eserviceinfo.com
Jestine
сергей
June 13, 2012 at 2:18 pm
у меня такая же проблема как и Анриана по работе монитора BenQ Q9C5 FP92E(включение каждый раз происходит по разному и выключение самопроизвольное...в основном при прогреве-после остывания опять могу включать.При выключении питание на 2-ом предохранителе есть).
Mihir
June 19, 2012 at 4:40 am
Thanks Jestine
I solved that was b 'cas of your sugetion
Jestine Yong
June 19, 2012 at 4:46 am
HI Mihir,
You are welcome!
Jestine
swapnil
July 16, 2012 at 4:00 am
i have problem to my dell 17 '' lcd which starts and turn off in few seconds continouly , what is problem behind that, the all capcitor are good in condition .
Jestine Yong
July 16, 2012 at 9:40 pm
Hi Swapnil,
It can be bad high voltage transformer or one of the backlight have problem.
Jestine
karik
July 22, 2012 at 9:18 am
hey jestine i cant get both FQU11p06 and FU9024N in my country 🙁 🙁 so can you tell me another equivalent for it plzz ?
Jestine Yong
July 22, 2012 at 10:21 am
Hi Karik,
Sorry no info on this. I have seen a repair tech put in a IRF9630 and placed a large heatsink. Not sure if it can work or not. You can try that but you must burn in longer. Try order the parts from utsource.net.
Jestine
Manolo
August 24, 2012 at 11:09 am
Hello, good afternoon: I have a Benq monitor FP91G + LED lights in green looks very devil logo background and put the orange light, could it be the inverter transistors shorted transistors open resistance? thank you very much friendly.
Jestine Yong
August 24, 2012 at 9:53 pm
Hi Manolo,
Sorry i don't get your meaning of "devil logo" and put the orange light? First is all the output voltages from the power supply good and stable?
Jestine
Manolo
August 25, 2012 at 7:50 am
Hello, good afternoon: I'm sorry, I was using the Google translator and translated to the Indian I am sorry, is that I have a model monitor BenQ FP91G light green all normal is at the bottom of the screen the logo very loose BenQ and the entire screen goes black, the power led becomes Orange?do, don't see images on the screen goes all in black and power led fixed in Orange, no video, I asked him if they could be inverter in short or open resistor transistors transistors? do these symptoms already than by what I've read often you pass that monitors BenQ, you think you this?
Thank you
very friendly.
Thank you!
Manolo Canarias
August 25, 2012 at 6:53 pm
Good afternoon:
I uploaded a photo FP91G + Monitor pointed red circles or damaged parts often extropean on these monitors, I read on the net, I would like to tell me if I'm right?
thank you very much
http://imageshack.us/photo/my-images/838/benqtu.jpg/
Jestine Yong
August 25, 2012 at 9:55 pm
Hi Manolo,
Yes those transistors will go bad in this model and it is a common fault. Before you replace the transistor make sure the high voltage transformer has no dry joints and the tuning capacitor value is good.
Jestine
salomon
September 30, 2012 at 2:18 am
when the power is on the moniter flashes ......
image is not obtained continualsly in my benq lcd tv 22inch.
Jestine Yong
September 30, 2012 at 8:28 am
Hi Salomon,
It could be bad e-caps, bad high voltage transformer or even one of the backlights have problem.
Jestine
Kristoffer
November 22, 2012 at 4:39 pm
Hi,
I did a rapair on a BenQ 19" LCD - FP937s this weekend, it had a bad e-cap and a cracked solder-joint at the power connector. After I had put it together, I did get a distorted image and flashing horizontal lines, I took it apart again and found out that the screen connector had not been seated properly.
Sorry for bad spelling,
best regards from a Norwegian service electronics technician 🙂
Jestine Yong
November 25, 2012 at 8:01 am
Hi Krisoffer,
Do you mean after you have placed the cable properly and now is working fine?
Jestine
cris
November 23, 2012 at 9:26 am
hi sir, i ask for my lcd monitor benQ fp731, i replace the bad capasitor and transistor c5707 is stell okay now but.. sumtimes is stell dark but i see the logo. if i press the auto adjusting it stell bright. but in a split sec then go again in a dark mode, what parts i fix sir. pls help me to fix my lcd monitor or sir pls... send me a diagram for that monitor i need your i dea sir thank a lot sir pls send me my email cris_12310@yahoo.com
Jestine Yong
November 25, 2012 at 7:57 am
HI Cris,
Sorry I do not have the schematic. Check for shorted one of the C5707 and even D10P60E Pchannel FET. Make sure the tuning cap at the high voltage transformer is good. Sometimes a bad backlight could cause the display to shutdown
Jestine
Harry
January 27, 2013 at 2:13 pm
Do you mind if I quote a few of your posts as long as I provide credit and sources
back to your blog? My website is in the very same
niche as yours and my users would really benefit from a lot of the
information you present here. Please let me know if this ok with you.
Thank you!
Jestine Yong
January 28, 2013 at 9:17 pm
HI Harry,
If you could put my blog link in the signature then yes you can use it
Thanks.
Jestine
Nigel
May 7, 2013 at 11:21 am
Thank you Jestine for all the info on this monitor.Though it's been helpful,I've still not fixed the monitor.So far I have changed the 4C5707,2FU9024N,2.22UF160V caps,pico fuse,& 2.16V1000UF caps.The monitor still comes on briefly and then cuts off.If I unplug the CCFL Tube's connectors, nothing lights up with #1&2 off and 3&4 on,with #1&2 on and 3&4 off,the screen is dim for few secs with BENQ Logo and then goes off. My questions for you are will this happen if CCFL is blown? If this is the case where can new tube be found and also THE schematicS for board,#48.L8302.A30? Again thank you in advance for youe help.
Jestine Yong
May 7, 2013 at 4:23 pm
Hi Nigel,
Sorry I do not have the schematic. In your case it can be one of the backlights or the high voltages transformer have problem. You can use other same size good LCD Monitor backlight for comparison. You can try ebay.com to see if there is any new tubes.
Jestine
Paul
May 8, 2013 at 5:44 am
Hi Justine, I have got a problem with 17" Benq LCD Q7T4, the power supply board is completely burnt but I want to modifify another power supply board and put it inside, now I can't figure out what are the power supply output voltages?
Jestine Yong
May 8, 2013 at 11:04 am
Hi Paul,
I do not have the service manual or the monitor with me other wise I could tell you the voltages. Usually lcd monitor will have two output voltages ie: 5v and 12 to 18 volt. This means the second voltage can be 12, 14, 16 or even 18 volt.
Jestine
reuven
August 14, 2013 at 5:27 pm
I have an 10(or 12?)leads Electrocardiograph USB module. (IQmark Digital ECG, Brentwood by Midmark)
It does not 'talk' with the computer.
Brentwood would not repair it nor will they provide service instructions / manual. They claim that this model is obsolete, and suggested to purchase the new model.
Any suggestions as to who may be able to fix the module, or how to fix it? (I'm an experimental physicist, so I know how to solder...)
Many thanks,
Reuven
Jestine Yong
August 15, 2013 at 11:12 pm
HI Reuven,
I have not repair such machine before but for a mother board USB that does not communicate it can be the driver or the south bridge IC problem.
Jestine
harold hugz
December 4, 2013 at 8:15 pm
Hi jestine how can you help me with my crt television with power on but no display .
Jestine Yong
December 4, 2013 at 8:27 pm
HI HAROLD,
Is there high voltage?
Jestine
Amir Mukhtar
April 11, 2014 at 10:59 pm
Thanks you Sir Jestine
you do Good and Marvelous to ERG Members Knowledge and Guidance.
I do Salute you with Lots of Well Wishes and Warm Welcome.
Thanks you Sir
Yours Student
Amir Mukhtar Ashrafi
Jestine Yong
April 12, 2014 at 10:41 am
HI Amir,
You are welcome!
Jestine
grigore
May 7, 2014 at 4:51 am
mosfet fu9024n or FQU11P06 (p channel) had equivalent?
Jestine Yong
May 7, 2014 at 2:17 pm
Hi Grigore,
Sorry no info on this but the best is to use original part number and you can try buy it from ebay or utsource.net
Jestine
Alfred
May 12, 2014 at 4:16 am
Hi,
I have a Benq monitor fp767-12. The problem is it is dead. Secondary voltages are ok but no led lights. Checked voltage on power key 3.2v ok. Any help where I can check the problem? Thanks
Jestine Yong
May 12, 2014 at 10:20 am
Hi Alfred,
If the MCU ic is getting the right dc supply voltage then most probably the MCU or the flash Rom DATA could have been corrupted.
Jestine
Alfred
May 12, 2014 at 1:08 pm
Hi Jestine,
Thanks for your email. The 3.2v from the power switch is arriving on U4, the power led is off even when the power is pressed. It probably is the flash rom which is corrupt. Can you please explain the proceedure to flash the rom if it is possible to do that please. Many thanks for your support.
Jestine Yong
May 12, 2014 at 2:46 pm
Hi Alfred,
You need a flash rom programmer and original program/data. Once you have these two items you can start to overwrite the good program into the flash rom.
Jestine
marian
August 3, 2014 at 4:13 pm
I have a problem with a good 12v source I would like a diagram if anyone can help me! Regards Marian, model LC-TM2018