Bad Benq 48.L1A02.A31 board for Hp1955L monitor
I have a HP 1955L monitor, The Benq 48.L1A02.A31 board ruined, ¿how can I get a new one? where to buy it? Where do I look for it? or Is it needed to repair?
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Re: Bad Benq 48.L1A02.A31 board for Hp1955L monitor
i recently had issues with this board too, but im no expert.
i couldn't just find a straight up replacement
when u say its ruined whats it doing? or failing to do?
do u have indicator lights? -
Re: Bad Benq 48.L1A02.A31 board for Hp1955L monitor
Post problem & pics.Originally posted by toothsvThere are 10 kind of people in this world: those that understand binary, and those who don't.- ASUS ROG Maximus IX Code
- Intel Core i5-7600K 3.8GHz
- 16gb GSKILL TridentZ RGB DDR4-3200
- 1 M2 SSD + 2 WD Blue 1TB (Mirrored)
- Windows 10 Pro x64
- GeForce GT1050
2 x Acer KA240H + 1 Vewsonic VP2130 21 (a cap replacement job
)
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Re: Bad Benq 48.L1A02.A31 board for Hp1955L monitor
Hi,
first of all my appreciation for such a good forum which I found just by chance... :-))
I am trying to fix a HP 1955 Monitor. Symptom was a short flashing up of the CCFLs at power up and a strong smell.
One SI4431 was badly overheated (the one more close to the center of the PCB), in fact it burned a hole in the the black foil under the PCB.
One 2SC5707 was shortened.
I replaced the SI4431 and both 2SC5707 in this section.
Now, the inverter works and lights all 4 CCFLs. But there is a sizzling noise coming from the area where the 2SC5707 have been replaced. I changed the 27p/3kV caps, the .22uF/160V cap. I resoldered the whole area but no change.
I started measuring with the scope and I can see a proper PWM on pin 9 of the TL1451 (which is the healthy second path). Pin 7 is somehow havily modulated/disturbed. Measuring on Pin 7 changes the frequency/charcteristic of the noise.
Anyone any idea of what it could be ?
Is there a proper schematic of the 48.L1A02.A31 board available ?
I know, it's close to the various other Benq boards, but matching component numbers would make it much easier.
Thanks
UliComment
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Re: Bad Benq 48.L1A02.A31 board for Hp1955L monitor
small sizzling noise from CCFL inverter board is quite common...Comment
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Re: Bad Benq 48.L1A02.A31 board for Hp1955L monitor
No, this is not a 'small sizzling noise'. It sounds like an electric discharge (which it isn't..). It changes basic frequency with brightness settings of the monitor.
And the sound is only an indicator for the faulty PWM regulation. The other channel with the proper PWM is almost completely quiet.
Possibly, the reason for this irregular feedback/regulation of the TL1451 was the reason for the damaged SI4431 and 5707s too. I do not know whether the noise was there before the inverter died....
UliComment
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Re: Bad Benq 48.L1A02.A31 board for Hp1955L monitor
There was an elevation of voltage from the electrical service, then the monitor started to blink and the image went off, then smoke from the back and a smell of plastic burned. I restarted the computer and the monitor gave image for a second and then went off again. Sent it to a bad tehcnitian, and the only hint he gave was shorted c5707. Changed 4 c5707 and two fqu11p06, tried again but still no picture. I upload the pictures, but it shows Q808 and Q809 with no original parts, those are parts that the first tech tried, but already changed to two c5707. The C824 is missing but was soldered back in place, not on the picture. Q815 and Q816 were replaced by two c5707. Q812 replaced by a new FQU11P06 same thing on the upper left side of the picture with a part with the big and raw piece of metal, replaced with a FQU11P06. Finally still no picture, just the power led on greenAttached FilesComment
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Re: Bad Benq 48.L1A02.A31 board for Hp1955L monitor
Anyone with will to help can write to my email: heliodent@hotmail.com. I have high quality pictures of the board, but coul not upload them, because they are 4mb and this thing only permits 2.99mbComment
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Re: Bad Benq 48.L1A02.A31 board for Hp1955L monitor
better pictureAttached FilesComment
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Re: Bad Benq 48.L1A02.A31 board for Hp1955L monitor
Hi,
I just wanted to inform you about my solution. The inverter died again and I could not find a reason for the new problem. It might be a pre-damage of the TL1451 from the first fault.
Totally pissed off, I de-soldered all the rubish from the inverter-side of the PCB and glued two small inverters (each 2 ccfl up to 400mm, price 5 USD...) on the free space.
Now it's as good as it was before. The automatic shutdown of the lamps has gone, but this is irrelevant for me anyway.
Congratulations to Benq - they managed to make it as complicated as possible while making severe design faults and giving it the least possible production quality. What a shame that HP uses such poor suppliers.
Greets
UliComment
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Re: Bad Benq 48.L1A02.A31 board for Hp1955L monitor
Pictures of the Franken-verter, please ...Originally posted by ulihuberThere are 10 kind of people in this world: those that understand binary, and those who don't.- ASUS ROG Maximus IX Code
- Intel Core i5-7600K 3.8GHz
- 16gb GSKILL TridentZ RGB DDR4-3200
- 1 M2 SSD + 2 WD Blue 1TB (Mirrored)
- Windows 10 Pro x64
- GeForce GT1050
2 x Acer KA240H + 1 Vewsonic VP2130 21 (a cap replacement job)
Comment
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Re: Bad Benq 48.L1A02.A31 board for Hp1955L monitor
Thank you to the OP for starting this thread because I just had the EXACT
same thing happen to my HP 1955L monitor.
This seems to be a design issue without question; I wonder what the cause
of the failure might be?
Enjoy my photos even though this thread is a year old. Maybe it will help
someone else get through their trouble.
Circuit Board ID
Failure Area
My circuit board appear to be a different version from the orignal post,
however the IC is identical. Type the red text into a search engine to
download the complete data sheet.
Be careful when removing the damaged IC as the pads may lift from the
circuit board (mine did slightly). It's a single layer board so using flywires
to the component directly is not an issue.
Protective Insulator
mmm...smells good mixed in with burnt Fairchild
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Re: Bad Benq 48.L1A02.A31 board for Hp1955L monitor
Hi everybody!
I have the same problem, I checked the transistors and i found that the Q815, Q816 are died and also the Q812 was shorted! I replaced the three parts and I still have the same problem no displaying on screen just a green light of the LED0...!!! I tried to see on the IC : TL1451A at the PWM output I have no signal and I measured on the pin 9 (+Vcc) and I found 0v...!!!??? so please if someone can help me to find out the solution.!
Thanks a lotComment
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Re: Bad Benq 48.L1A02.A31 board for Hp1955L monitor
Note post #3. Top and bottom, please. See my signature for more information.
Did you resolder the transformers?
Did you check the fuse?
Again and again this is repeated. Repair advice is a case of Garbage In, Garbage Out. The more information you give us, the more (and better) assistance we can give you.
PlainBillLast edited by PlainBill; 01-05-2011, 09:40 AM.For a number of reasons, both health and personal, I will no longer be active on this board. Any PMs asking for assistance will be ignored.
Never be afraid to try something new. Remember, amateurs built the ark. Professionals built the Titanic.Comment
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Re: Bad Benq 48.L1A02.A31 board for Hp1955L monitor
Thanks a lot to everybody!
Finally I repaired my LCD!
I have changed the two transistors C5705 et the MOSFET J598 and the Picofuse PF701 and I soldred also HT transformers!
special thank to "Retiredcap"Comment
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There are 10 kind of people in this world: those that understand binary, and those who don't.- ASUS ROG Maximus IX Code
- Intel Core i5-7600K 3.8GHz
- 16gb GSKILL TridentZ RGB DDR4-3200
- 1 M2 SSD + 2 WD Blue 1TB (Mirrored)
- Windows 10 Pro x64
- GeForce GT1050
2 x Acer KA240H + 1 Vewsonic VP2130 21 (a cap replacement job)
Comment
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Re: Bad Benq 48.L1A02.A31 board for Hp1955L monitor
Thank you for all the valuable informationComment
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Vizio e601i-A3 - Has Sound and Display, But No Backlight - Bad Power Supply Board or Bad LED Bulbs ?I was given this TV from my great uncle. He said it just wouldn't turn on one day out of nowhere, replaced the TV, and gave it to me to possibly fix and use for myself.
Upon bringing it home and plugging it up, it showed a standby light.
I powered it on and without a flashlight, the display showed the "V" but the lighting is very dim, but visible.
The screen seems to blackout and stay black, but with a flashlight I can see the display.
With my Playstation 4 connected via HDMI, and running a game I can hear sound.
Assuming... -
Hi, this is my personal laptop, which the original board (lets call it Board A) blew up PU8700 (TPS51486), making a hole on the board, i had left the laptop at my desk one day with the battery fully charged and didn't touch it for a week, but when i tried to turn it on it didn't
Thought the battery was dead, so i plugged in the charger then tried to power on, the power LED blinked once, charged LED still orange, unplugged the charger, plugged in again and I noticed the "magic smoke" smell, so i unplugged the charger, removed the back cover and saw the blown IC (the "magic... -
Hey everyone,hope everyone is fine, I got an issue hoping you guys can help me,
I got a HP V193 monitor it has a E59670 now i got a few of these, been using them for long time now, however this particular monitor was blacking out for a few times then after unplugging and plugging it back in it gets back to normal until now its dead.
I tried switching the power supply board with another similar monitor and it works,so I'm trying to fix this power supply board I got some basic in electronics as a hobbyist.
Steps taken so far:
Checked all...02-21-2023, 04:00 AM -
Normally, I never post repairs this quick after I do them, because… I am usually very slow.
But today, I’m making an exception here. Why? No idea. Perhaps only because the repair details are still “fresh” in my head… which is ironic, given this is a 16 year old monitor that hardly anyone will care about today. It is new to me, though. 
I picked it up last November from someone on my local Craigslist. It wasn’t very close to where I live, but was close to a family friend that I had to go visit anyways. So after watching the posting on Craigslist for a few weeks and seeing it getting...
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Hi There,
This TV was auto switching off after few seconds with some vertical lines on the screen, so got a new TCON board and replaced it.
After replacing the TCON board it was working fine and i set it up with everything, used for few hours, then had the bright idea to update the software on it. During the update process, TV switched off and now no audio or video. No relay switch sound.
More Details
TV Model - LG OLED77G1PUA
Got the same exact TCON board from TVPartsToday and replaced it. But didnt transfer the EPPROM data (didnt...
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