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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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Jose Antonio
July 11, 2009 at 12:11 am
good afternoon q7c4 benq monitor fails to turn on and then turns off heated filter change defective c 712 1000mf 10.0vy work 5 days and return to failure nececito same diagram porfabor you change the filter is well thanks
admin
July 14, 2009 at 9:13 pm
HI JOSE,
Sorry i still don't understand the meaning. Do you mean after change the capacitor it work for 5 day? Then what happen to the monitor-is it no power, shutdown or dim display?
Jestine
ANAND( India )
August 2, 2009 at 2:39 pm
Thanks Lot Guru (Teacher) !!!
My bena 17" lcd has same problem of display,Actualy i am replacing 1000/10v
capacitor (2 qty) which r burn,but stll same problem.But as per u'r suggetion i repalced c5707 which r short,replaced & solved my problem,
Once Again Thanks looooooooooooooooooooot
admin
August 2, 2009 at 11:03 pm
Hi Anand,
Congratulation!
Jestine
Terry Salmas
August 14, 2009 at 5:15 pm
Hi Justine,
I own a BENQ FP731 monitor the problem is when i push the Power button the BENQ logo appears on the screen with a white horizontal line above the bottom of the screen and stays on about 2 seconds and then the backlights off but the Power button Led stays green for about 30 seconds and then goes orange. I changed the 4 SC5707 transistors and the 2 FU9024N with FU9024 replacement and also i changed all the capacitors on the board and the Bell 3A fuse. But still the same problem. Please, would you like helping me ?
admin
August 14, 2009 at 9:58 pm
Hi Terry,
Did all the C5707 and the FU9024N have problem or you just directly replace it? Orange LED usually indicates fault in the motherboard particularly the MCU. When the backlight was off is the output voltages still good/stable?
Jestine
Terry
August 16, 2009 at 3:30 am
When i first unscrew the Benq FP731 the Bel MS 3a was burnt and i replace that burnt fuse with a wire and when i put it on power one FU9024N was burnt and smoked and 2 C5707 was burnt.
So i changed all the capacitors on the board except the big capacitor Also i replace the 2 burnt FU9024N with 2 new FU9024 and the 4 C5707 with new 4 C5707 and finally the Bel MS 3a fuse with a new one.
When the Backlights are off the voltage in pin 9 (VCC) of TL1451 IC is 16Volt until the Power Led change to orange colour and Volt drops to 0V.
What to check now ?
Terry Salmas
August 16, 2009 at 5:44 pm
Hi again Jestine,
The voltages are off when the Green Led from Power goes Orange after about 20-30 seconds. The same thing happens without connecting the two small plugs for the Fluorescent lights. The 9th pin (VCC pin) from the TL1451A(PWM-Pulse Width Modulation) from the spec's i have must supplied with 51 Volt but is 16 Volt and then goes 0Volt.
admin
August 16, 2009 at 10:39 pm
Hi Terry,
From your description it is most likely the mainboard is the culprit. It is the mainboard who send an On signal to the start circuit in the inverter board in order to let the supply voltage to go to the inverter VCC pin. I have came across quite a number of LCD brand with this problem and the solution is to replace the mainboard.
Jestine
Terry
August 17, 2009 at 7:33 pm
Is it possible maybe the transistors aren't the same in specs?
I replaced the two FU9024N with two FU9024 aren't the same and what the differences?
When i play with power button on & off a few times the transistors Q760 and Q759 are getting hot, is it right ?
admin
August 19, 2009 at 7:31 pm
Hi Terry,
Generally both can be used and if the transistors are hot to touch then it has problem and if it is just warm then i presume it to be okay. If the inverter ic supply has zero volt after shutdown then most likely is the fault of Mainboard.
Jestine
Terry
August 19, 2009 at 9:30 pm
The inverter IC TL1451ACN in VCC Pin 9 has 16 Volt when i push the Power button on and led turn green but after 2 sec the backlights off but voltage remains 16 volt in VCC 9 Pin of inverter IC while i wait about 23 seconds and power led goes orange and Volt goes 0 in VCC 9 pin of inverter IC. I test also the reference output voltage in pin 16 of TL1451ACN and is 2.4V minimum as specs of TL1451A.pdf said.
I suspect that something else is the problem and not the mainboard with the PW133A chipset also i test all the surface mount transistors and capacitors there and is ok.
Where i can found the program and firmware that i can try to re-flash the monitor ? I saw on mainboard 2 small chipsets with the name ATMEL.
Terry
August 19, 2009 at 10:36 pm
Justine sorry again for disturbing you but i tried another thing :
When i short circuit with my screw-driver pins 11 and 10 of the TL1451ACN then the first backlight lamp glows but the first transistor Q759(SC5707) getting quickly too hot so thats why the inverter IC maybe scans an error in the circuit and thats why the inverter IC switching off the backlight lamps maybe to save the transistors from burning... I thought.
The same happens when i short circuit pins 6 and 7 of inverter IC and the second backlight lamp glows and the transistor Q740 getting too hot so quickly, so i removed the screwdriver quickly before burn something...
Your thought ?
admin
August 20, 2009 at 7:30 pm
Hi Terry,
Sorry i do not have the firmware for the IC. As for shorting out the inverter IC pin i have no idea why the transistors get hot because i do not have the same unit at my office to test it out. In your case somehow i'm very sure is the MAINBOARD problem particularly the MCU IC.
Jestine
Terry
August 27, 2009 at 4:17 pm
You mean the PixelWorks PW133A chipset is faulty ?
Can i find that part anywhere ?
Ronny
August 29, 2009 at 8:29 pm
Hey Jestine,
I own a 19" LG L194WT. I've had it for over 3 years no problems, but just recently, everytime i turn on my PC, the monitor only comes up with a white screen for a few seconds then loses power completely while the PC is still running. What could be the problem with it?
Thanks in advance,
Ronny
Ronny
August 29, 2009 at 8:36 pm
Oh, I forgot to mention, even when I try to turn it on while the PC is off, it still comes up with white screen for a few seconds then goes blank but it doesn't power off completely as the power button light goes to standby.(Orange Led color)
Thanks once again,
Ronny
Andrew
August 30, 2009 at 6:18 am
Hello!
Thanks for the suggestion - my Q7T4 just went blank one day (but still has power light on) - and I thought maybe I'd try to give it a fix!
As Jatin mentioned about the eserviceinfo.com site - you can get the Service Manual for the Q7T4 from there - I got it without registering or anything, just from the download page, at:
http://www.eserviceinfo.com/downloadsm/35483/BenQ_Q7T4-FP71G.html
Wish me luck, I'm going in! 😉 & Thanks! again! 🙂
admin
August 30, 2009 at 3:29 pm
Hi Terry,
Yes it is possible but i have no info where to get it.
Jestine
admin
August 31, 2009 at 9:22 pm
Hi Ronny,
If all the output voltages are good then i'm afraid the lcd panel or the mainboard have problem. But usually when the power LED turns orange, the mainboard was the culprit.
Jestine
christianne
October 10, 2009 at 2:31 pm
hi jestine!.. did FQU11P06 can replace in c5706 on AOC LCD LM725?..
admin
October 10, 2009 at 4:01 pm
HI Christianne,
No it can't because FQU11P06 is a FET and C5706 is a normal bipolar NPN transistor. You need to get back the original part number.
Jestine
christianne
October 10, 2009 at 9:42 pm
ok... can you help me, what can i replace to c5706 on my AOC LCD LM725?.. its hard to find c5706...
admin
October 10, 2009 at 10:53 pm
Hi Christianne,
This comment was posted not long ago by Grabiel:
"Another correct substitute for c5707 transistor is c5103. I have changed a couple of c5707 transistors with the c5103 and it works perfectly as the original part numbered. using the combination of both c5707 and c5103 wont have any problem."
Gabriel K. Agbemenya
For your information C5706 can be replaced by C5707
Jestine
christianne
October 10, 2009 at 11:16 pm
theres any other substitute for c5706 or c5707 transistor?..
admin
October 11, 2009 at 6:27 pm
Hi Christainne,
Sorry no more substitute part number.
Jestine
Jayasheela
October 23, 2009 at 3:29 pm
E173FPB unit is having Intermittent Display defect .
Inverter defect Q739,Q740,Q759,Q760 is short (C5707 Transistor)
Can you please provide the package sl.no and also provide equivqlent component for C5707.
admin
October 23, 2009 at 8:51 pm
Hi Jayasheela,
May i know what package? As for the C5707 the best is to use back the original part number.
Jestine
Wes Linton
October 23, 2009 at 10:03 pm
Hi Jestine
Ran into your site looking for information to repair HP f1703 monitor. Have one burned c5706 transistor and found loose/cracked solder joints there also. Also found apparent cold joints on one other transistor. I understand c5707 will work in place of c5706, Are there any other reliable replacements, possible with higher power capability and/or larger tabs to enable heat sink applications. Also I may look at ways to improve ventilation through monitor.
Thanks
Wes Linton
admin
October 25, 2009 at 8:50 pm
Hi Wes,
The best is to use back the C5707 transistor. You may install a small CPU fan (5 volt) internally.
Jestine
Naresh
October 28, 2009 at 7:46 am
1 -Bel 3A 3 Amp ms 125V Fuse.
4 -PCS 2SC5707 Transistor.
2 -PCS FU9024 Transistor
Hello
quation for you all above parts will fix my fp71g+ monitor?
Please advice
admin
October 28, 2009 at 10:27 am
HI Naresh,
You have to buy those parts and test it out. Check also for dry joints!
Jestine
Naresh
October 29, 2009 at 1:40 am
thank you
I will try and up date to you
BIKRAM PARIYAR
October 29, 2009 at 6:44 pm
DISPLAY DO NOT WORK.
admin
October 29, 2009 at 8:26 pm
Hi Bikram,
Have you try all the method mention in this post?
Jestine
King Peza
November 12, 2009 at 9:59 pm
I have got a BenQ "17" LCD monitor with the HD 15 connector cut off , i want to attach it back , can you please assist with the pinouts?
admin
November 13, 2009 at 7:41 am
Hi King,
Try this link:
http://en.wikipedia.org/wiki/VGA_connector
Jestine
Jorge
November 15, 2009 at 10:13 pm
Hi!
Well, I have a problem with the Benq Q7C4. I´m not a professional with computers, and nothing similar. My knowledge is very very basic.
Well, I want to ask you if you have any solution to this problem, I dont know if its a problem with an easy solution, of with a hard solution, of without solution, but well, this is:
When I turn on the monitor, the blue light turns on just a second, and it turns off. If I hear the sound, when I push the button, it sounds as always, but the second after that, It sounds like if it doesnt have power to turn off the screem and it restart the "power" but the screem doesnt light up. And, if I press the button without taking away my finger, the light, after 2 o 3 seconds, turns yellow (as if we turn on the screem and it doenst recieve any signal, but I´m sure the problem is of the screem, not from the computer)
well, I dont know if I have sayed it clearly, I dont think so cause my english is very basic, but I hope you can help me
thank you, bye
admin
November 16, 2009 at 8:24 pm
Hi Jorge,
Is the output voltages from the SMPS tested normal when the monitor have problem? If yes then suspect a bad mainboard. If no then i guess you may need to check the power section.
Jestine
Morgan
November 18, 2009 at 1:04 am
I have a Benq model Q7S3 monitor, powers up with white screen only. Any idea as to what the cause might be.
Thanks Morgan
admin
November 18, 2009 at 7:02 am
HI Morgan,
White screen problem usually cause by bad LCD PANEL. If all the voltages present at the LCD controller board then replace the LCD panel.
Jestine
Naresh
November 27, 2009 at 8:36 pm
Good mornning
I did follow your guidence for repair for benq q7t4. and I did able to fix that thank you
Now I am trying to fix dell e152fpb. screen text comes up when you power on and disapper in less then minutes.every time you power on.
any thought on this.
I did chech all parts like q7t4
admin
November 28, 2009 at 5:06 pm
HI Naresh,
After shutdown, is the supply voltage still present at the inverter vcc pin?
Jestine
Naresh
November 29, 2009 at 7:47 am
Good eveenning
happy thanks giving day
on this monitor where can I mesesur the vcc volt
admin
November 29, 2009 at 5:10 pm
HI Naresh,
At the output of the SMPS.
Jestine
Gozimat
December 29, 2009 at 11:33 pm
Hi,
my Benq FP71G+S Model Q7T4 has a 48.LIC02.A10 board. It appears to have (ST)D10PF06 in place of the FU9024N/FQU11P06. There are kits available on ebay which have the C5057s and FU9024Ns plus fuse. Are the D10PF06 and FU9024N interchangable ?
Thanks
admin
December 30, 2009 at 2:30 am
Hi Gozimat,
The D10PF06 SPEC is higher. Sometimes a lower spec like the FU9024N could be used too. I guess you may need to test it out. If it runs hot then don't use it. Test it under high resolution and if it is only warm then you can use it as a replacement.
Jestine
albert
December 31, 2009 at 1:22 am
please help. I brought my benq fp71g to a repair shop due to blank screen (but with green LED on). However, it was not repaired due to lack of parts. But all 6 pcs transistors were removed and returned to me in pieces. Please show me where to put back these transistors. thank you
admin
December 31, 2009 at 6:47 am
HI Albert,
Do you have the transistor part numbers as i do not have this model schematic?
Jestine
Gozimat
January 5, 2010 at 4:28 am
Hi Jestine,
thanks for your response. I bought the kit and soldered them in. I am currently testing to see about the heat issue.
Thanks for the great site and help.