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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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admin
January 31, 2011 at 4:32 am
HI Christianne,
Have you check the dry joints in the high voltage transformer? What about backlight? One of the backlight problem could cause such problem too.
Jestine
yusuf
February 1, 2011 at 7:03 am
Dear Mr Young
can you tell me what can I cange the IC SG6841 with what????
I have the AOC LCD 19` not starting power I find the IC SG6841 may by not good
what is the equivelant IC I can repaire it
Thanks
yousuf khaled
admin
February 1, 2011 at 9:39 am
HI Yusuf,
I suggest that you use the original part number and you cahn but one from this website:
http://www.utsource.net/sg6841.html
Jestine
Christianne
February 2, 2011 at 12:45 am
no dry joints found in high voltage transformer!.. how can i check the backlight?.. any other problem can cause?..
admin
February 2, 2011 at 9:31 am
Hi Christianne,
Chances is high in the backlight. You need to compare it with a working backlight to know if it good or bad or you can use a tester (below link):
http://www.hrshop.es/index.php?command=viewProduct&id=73211
Jestine
luke
February 6, 2011 at 10:39 am
Hi,
I have a Benq FP91G+ that the screen has suddenly gone blank. The green light comes on and then turns orange after about 25 seconds (without the data cable plugged in) but no image at all. I opened it up to look at the board and could not see any visible signs of bad caps, transistors or burn marks. Any suggestions as to what could be the problem?
admin
February 7, 2011 at 3:51 am
HI Luke,
First, connect the VGA cable, and see if the power led will turn to orange or not. If not then make sure that there are good and stable voltages from the SMPS. Check also if the inverter is receiving any voltage or not. If no voltage most probably the MCU may have problem.
Jestine
Christianne
February 14, 2011 at 11:38 am
i check all backlight and its work good!.. the problem is still the same, what can i do now?..
admin
February 15, 2011 at 8:12 am
HI Christianne,
Is the inverter ic still getting supply voltage after the display have shutdown?
Jestine
Hans
February 25, 2011 at 4:49 am
I have BenQ FP202WA. Monitor can't power up, no indicator light, no nothing. I replaced all capacitors (47, 220, 470mF), resoldered the most of soldering points. No shorted semiconductors. Still nothing happend, monitor is still dead??? Can help me with some idea? Unfortunately, I don't have schematic or SM...
sandeep
February 26, 2011 at 12:50 am
I wants some parts of benq LCD monitor..
plz help
admin
February 26, 2011 at 10:57 am
Hi Sandeep,
Try order it from http://www.utsource.net
Jestine
admin
February 26, 2011 at 11:00 am
HI Hans,
If there is no output voltages from the smps then check all the components in the power side and if possible direct replace the power ic and retest. If there is output voltages then suspect a bad MCU in the mainboard.
Jestine
Hans
March 2, 2011 at 3:21 am
Hi Jestine,
again with my BenqFP202WA. There is new moments. I found one picofuse 2A opened. It's for 5V line (Vcc for pwm ic TL1451A). Also I was found that 19V is OK. When I replaced bad picofuse, monitor woke up, power LED come back, but only WHITE screen???
admin
March 2, 2011 at 5:06 am
HI Hans,
If the cable is connected good between the mainboard and lcd panel then the lcd panel is the fault assuming if there is 5 volt entering the lcd panel controller board.
Jestine
luigi182
April 1, 2011 at 7:49 am
Hi Jestine!
I took my Q7T4 to a repair center, they said, they can't repair it, because can't order the two high voltage transformer. Can you tell me its number about I can order it? THX
admin
April 1, 2011 at 8:11 am
HI Luigi,
Sorry i do not have this monitor in my workshop otherwise i could open it up and look at the part number.
admin
April 1, 2011 at 8:13 am
HI Luigi,
Sorry i do not have this monitor in my workshop otherwise i could open it up and look at the part number. In fact you can open the monitor and look for the part number. You may also try to contact Luca at info(at)lavinci.it to see if he has the part or not.
Jestine
luigi182
April 8, 2011 at 10:33 pm
Hi Jestine!
Thanks for your help! I found it : 19.26048.001
chris zammit
April 8, 2011 at 11:51 pm
Hi
i`m new to this sector,i have my first lcd monitor to work on the benq t705. I`m having a problem locating the picofuse as I dont know which is it.any help would be much appriciated. thanks in advance chris
admin
April 9, 2011 at 1:19 am
Hi Chris,
There are 2 types. It is located in the secondary side in the 12 volt line. One is in black color and other type is like the below picture:
http://media.digikey.com/photos/Littelfuse%20Photos/PICO%20II%20R251%20SERIES.jpg
Jestine
luigi182
April 9, 2011 at 3:30 am
Can you tell me is in Benq FP71G same (19.26048.001) transformer, or not?
admin
April 10, 2011 at 3:20 pm
HI Luigi,
As mentioned earlier that since i do not have this monitor in the workshop thus i could not know the part number. Have you try email Luca because he sells lot of transformers?
Jestine
lee
April 15, 2011 at 7:43 am
hi... i know i cn replace FQU11p06 with j598? thx
lee
April 15, 2011 at 7:56 am
hi.. my lcd benq fp71g+, actually my problem is, turn on 5-second like that then no more backlight... i had replace the 2set of c5707 and 2capacitor as well.. but problem still not solve. may i know which part i shd change? thx
admin
April 15, 2011 at 7:08 pm
Hi Lee,
I have not try that part number before. You can try it and if it gets hot within seconds or a minute then you know it can't be used.
Jestine
admin
April 15, 2011 at 7:09 pm
HI Lee,
It can be dry joints in the high voltage transformer or one of the backlight is bad.
Jestine
lee
April 17, 2011 at 11:03 am
ok... thx ya..
btw, now i have a benq fp731... in beginning the problem is when i turn on the lcd, its got image... jz dun hv light.. after i chg the 3A fuse.. the lcd is working fine.. but its nt last long, i thk i used for few days, got one day i turn on the lcd, the same problem again, i check again, the fuse is broken, i replace n try on, same problem.. at d end, the fuse broken again, i think i change 3times d, may i know which component mostly cause this problem? thx a lot!!
admin
April 18, 2011 at 12:26 am
HI Lee,
Check if there is any leaky transistor and make sure no dry joints in the high voltage transformer.
Jestine
Bruce Briz
April 21, 2011 at 7:02 am
Hello there,
Fantastic website! Can you give me some trouble-shooting pointers please. I'm having a problem with a Benq FP71E - it is still giving a good picture, however, the on/off button no longer works and none of the other control buttons work. I've split it open and cannot see any massively bulging electrolytics - so I will do a few esr measurements around the power supply section - but beyond this I really haven't a clue. Any suggestions will be gratefully received.
admin
April 21, 2011 at 10:01 pm
Hi Bruce,
You may need to check on the cable connection and the buttons. If all check to be good then the problem is in MCU because all signals from the buttons are coming from the MCU.
Jestine
Bruce Briz
April 22, 2011 at 9:54 am
thanks for this, appreciated...
brucebriz
Bruce Briz
April 22, 2011 at 11:48 pm
Hello again,
Well! Re my Benq FP71E, switches checked (and a touch of contact cleaner) and cable connections reseated and all now appears to be working normally, including on/off switch and all buttons.
thanks for your help
Bruce
admin
April 23, 2011 at 1:18 am
HI Bruce,
Congratulation!
Jestine
lee
April 23, 2011 at 12:41 pm
hi...
regarding to my fp731 benq lcd,i had checked, there are no any leaky transistor and no dry joints in the high voltage transformer after i re-soldered it... but the problem not solve, my lcd still got same problem, which is turn on got image but there no light. i had replace another working power board, i confirmed the backlight of lcd panel should be no problem. i use 2 power board 1 working n 1 faulty n do comparison, in fact i really cant find out what the problem, cz i lack of experience. may i know what the common solution for this model of lcd? thx ya.
admin
April 24, 2011 at 2:02 am
HI Lee,
You have mentioned that the display will goes off after sometime. When you turn it on for a minute or two, turn the monitor off and place your hand on the inverter board area to see if there is any component that is hotter than normal. Pay particular attention on semiconductor because you have said that the replace fuse already blown for the third time.
Jestine
chris
April 24, 2011 at 5:41 am
Hi me again 🙂 i got another benq for repair and this gets the picture for 2 seconds and after it switches of.Is this the same symptom as to change transistors and fuse?
thanks in advance
OMAR
April 24, 2011 at 7:04 pm
HI,
I have LG L222WS. suddenly, while I was using it, it turns completely white connected or disconnected to the PC. is it a problem with the power supply board backligt, lcd pannel? i opened it and all connexions are OK? capacitors ?
any one have an idea
thank you so much
admin
April 25, 2011 at 5:05 am
HI Chris,
Yes but you also need to check the backlight too.
Jestine
admin
April 25, 2011 at 5:10 am
HI Omar,
If there is supply voltages to the lcd controller board in the lcd panel then the lcd panel is the problem.
Jestine
valerie ricchio
May 7, 2011 at 8:03 am
I have a HP 1940 lcd. When i attach it to a PC and power up the display I get a amber light then a blinking green light and no video. The Capacitors look good. I have search your site and various other sites, but have not found this problem listed. Can you help me?
admin
May 7, 2011 at 10:13 pm
HI Valerie,
What happen if you did not connect the VGA cable-is the led still blink? If all the voltages in the mainboard are good then suspect a bad MCU because the power led signal is coming from the MCU.
Jestine
marvin
May 10, 2011 at 5:29 am
hey im having trouble with my benq 17" . when connected to the PC i turn the monitor on and the green light goes off in like 2 seconds and every time i press the power button on the monitor. when i hold down the power button it at most flashes the desktop the turns off again. the only thing other than that i can see is the logo screen, there is no error no signal detected or anything like that when the cables are unplugged. please help thanks
valerie ricchio
May 10, 2011 at 7:59 am
No VGA, same blinking led. What is a MCU?
admin
May 10, 2011 at 10:28 am
HI Valerie,
Then i guess the MCU have problem. MCU is micro controller unit.
Jestine
admin
May 10, 2011 at 10:31 am
HI Marvin,
It could be few bulged/bad e-caps. Try open it up and make sure the output voltages are good and stable.
Jestine
valerie ricchio
May 11, 2011 at 11:11 am
I am a high school teacher and I think replacing the MCU is beyond my skills (I figure it is one of the chips on the digital video board), so I looking at replacing the benq 48.l1g01.a02 digital video brd to fix the MCU issue. It is coming up as a 1740 instead of a 1940 card (for an acer instead of a HP LCD). So is this interchangeable, and am I correct on the level of skill required to replace the unit. We are trying to fix the LCD to make money for our computer club and the cheapest price I can find is $30. Thanks in advance.
admin
May 12, 2011 at 8:03 am
HI Valerie,
I have not replace that MCU before to another model but as far as i know different model use different programs in the MCU.
Jestine
valerie ricchio
May 12, 2011 at 8:10 am
What level of skill is required to fix the MCU on an HP1940, and do you have any recommendations?
admin
May 12, 2011 at 9:21 pm
HI Valerie,
If the MCU is socketed then just pull out and replace with a new one or reprogram it with a programmer-it is an easy job. If the MCU is mounted then you need a smd rework station to do the job and this will need some extra skill.
Jestine