Re: Yusmart 229IP-P 22" LCD Monitor Dead
Does the fact that the power board is not outputting 24v have a bearing on things?
Does the fact that the power board is not outputting 24v have a bearing on things?
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Re: Yusmart 229IP-P 22" LCD Monitor Dead
In general, the 5V DC is used for most or all of the functionality that is required on the logic board. Voltage regulators on the logic board take that 5V DC and change it to 3.3V DC and/or 1.8V DC as required. The power on/off functionality is located on the logic board.
So there is proper voltage on the logic card as you verified. You also verified there is continuity from the keyboard panel to the logic card.
The 12V, 19V, or 24V DC is usually used for the inverter section of the board. There is 24V DC on the power board, but we have not traced it any farther right now because it is not required on the logic board.
If the power LED was lit (any color), then we would be focusing our attention back on the inverter section and tracing out the 24V DC.--- begin sig file ---
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Re: Yusmart 229IP-P 22" LCD Monitor Dead
If the trace path that you find happens to lead through an electrolytic capacitor, you might want to replace that one.
The smaller ones found on the logic rarely are bad, but when they are bad, they can fail without any sign of visibly bloating. They can have high ESR (ohms) or be out of uF tolerance.--- begin sig file ---
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Re: Yusmart 229IP-P 22" LCD Monitor Dead
I would be really curious about something. Is there any voltage at any of the pins at the front control panel? I would expect to have at least one ground wire and at least several that have a reference voltage I am going to guess 5v may be the reference. If a reference voltage is there on any of the pins dose the voltage go low or to near 0v when different buttons are pushed. The voltages I suggest are just a GUESS, but the monitors I have looked at that I suspected a problem with front control panel have all been able to change the state of the reference voltage[going from a high to low voltage as buttons are pushed]Another thing to concider is that a monitor can work without the front control panel hooked up.Whatever I do, I consider it a success, if in the end I am breathing, seeing, feeling and hearing!
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Re: Yusmart 229IP-P 22" LCD Monitor Dead
I have checked the voltage at the power button and it reads as 3.4
When I press the button it drops to nothing.
I am having problems tracing the power line to the IC though, the trace just dissapears underneath some other chips and then I lose it!
I have been unable to find a datasheet for it and have even contacted the company that originally made it with no luck
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Re: Yusmart 229IP-P 22" LCD Monitor Dead
Also, I have been unable to find any fuses on the logic board, does this sound right or should there be some?Comment
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Re: Yusmart 229IP-P 22" LCD Monitor Dead
Well the power button is doing something, Whether it being right or wrong I don't know. As retiredcaps suggests a data sheet would be very helpful. I would hope now that someone with a similar monitor may be able to verify if the 3.4v is a correct reading.I have checked the voltage at the power button and it reads as 3.4
When I press the button it drops to nothing.
I am having problems tracing the power line to the IC though, the trace just dissapears underneath some other chips and then I lose it!
I have been unable to find a datasheet for it and have even contacted the company that originally made it with no luck
Al.Whatever I do, I consider it a success, if in the end I am breathing, seeing, feeling and hearing!Comment
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Re: Yusmart 229IP-P 22" LCD Monitor Dead
I've been real busy lately but finally managed to find some time last night to try and trace the power button back to the IC. I have attached an image of how far I have got....... not far!
I am still having no luck with finding a datasheet for the IC, the manufacturer haven't come back to me and I can't find anything anywhere
Attached FilesComment
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Re: Yusmart 229IP-P 22" LCD Monitor Dead
I have also asked Quotidian at the post https://www.badcaps.net/forum/showth...d=1#post125888 if he could measure the voltage he is getting at his power button.
Hopefully this will confirm if mine is ok or not.Comment
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Re: Yusmart 229IP-P 22" LCD Monitor Dead
My monitor has the same power and main board as your monitor, but my monitor is an Envision G218a1. Exact same issue, no power. I could check my voltages to compare to yours, but being it is the same issue... I'd assume the readings wouldn't do you any good.
I see you haven't posted in 2 weeks... have you found a fix?
Thanks!Comment
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Re: Yusmart 229IP-P 22" LCD Monitor Dead
OK. I've tested all the same tests that fusionmax has. My only difference is:
My cable coming from my power board going to the main board: it has a voltage of 2.82VDC at the black wire (between the white and brown wires).
I also have the same voltage at the control buttons as he does (though being my monitor is dead too, I'm not sure if they are correct).Comment
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Re: Yusmart 229IP-P 22" LCD Monitor Dead
Hi Billy,
I've not found a fix yet, i'm just working on making a diagram of the logic PCB to make things easier to trace.
I should have something done in the next couple of days so I can post something up.
Have you managed to find a datasheet for either the logic PCB or the IC from the logic board?Comment
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Re: Yusmart 229IP-P 22" LCD Monitor Dead
To be honest, I haven't been looking too hard. I have like 4 monitors I'm working on, and upon doing the initial research on this one... I came across your post and thought I could try to help. If I do, I'll post it here of course.Comment
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Re: Yusmart 229IP-P 22" LCD Monitor Dead
Ok, so I've finally managed to find some time and traced the power button back to the IC on the Logic board.
It appears to be at pin 50 and doesn't go through any capacitors. I have attached some images showing this.
Can anyone give me my next move?Attached FilesComment
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Re: Yusmart 229IP-P 22" LCD Monitor Dead
Hate to be a bumper but has anyone got any ideas?
I am at a loss!Comment
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Re: Yusmart 229IP-P 22" LCD Monitor Dead
At this point, if you go back and take a look at the photo #2, post #11, you will see 4 8-pin chips. I'm using the vx2235 schematic (page 48), and these chips are marked Q905-906 and Q911-912? These chips each contain 2 mosfets. Please check each of them for possible shorts. These chips are responsible for generating the sine wave used by the inverter transformers to generate the high voltage required by the CCFL's. However, if they are shorted will usually blow a fuse, but still worth a look.Last edited by jetadm123; 10-20-2010, 09:45 AM.Comment
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Re: Yusmart 229IP-P 22" LCD Monitor Dead
hi I have one of these trying to fix. The vx2235 has the same power board but differnt logic board
forgot to say
mine has only the green power light on, nothing else
last one like this was the eepromLast edited by bonney; 10-20-2010, 10:13 AM.Comment
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Re: Yusmart 229IP-P 22" LCD Monitor Dead
Hello bonney and welcome to the forum! If you've had a chance to read through this thread, you'll see that there was the question of having 24V on the brown wire on the wiring harness on the power/inverter board. It shows on the viewsonic schematic, but shows up 0V on the Yusmart. We don't know if this normal for the Yusmart or not. Can you please verify?Comment
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Re: Yusmart 229IP-P 22" LCD Monitor Dead
Hi Jet and thank you for the welcome
24V does not go to the logic board, if you look at post 11 picture 2 you can just make out no join on pin 9Comment
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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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Hello Badcaps Community,
I purchased a preowned AOC monitor that is not working and out of warranty. It was sold as not working. I am looking for guidance on self-repair. In particular, I am after the firmware for the monitor. At the end, I have included monitor model information and links to pics and vids of the issue.
The problem is that it will not display a picture on any of its inputs. And the on-screen menu does not appear. The power button works properly. It powers on with the remote as well. But the on-screen menu does not appear, even when not connected to any... -
Hi Everyone
Lately I am experiencing the deja-vu incident on one of the led monitor like this.
https://www.badcaps.net/forum/troubl...lashing-on-off
The monitor is HP 27es LED Monitor
https://h30434.www3.hp.com/t5/Deskto...e/td-p/6804692
The monitor will randomly blackout and display no signal and will recover again.
Sometimes need to power and off again to restore the display but... -
Good evening, gentlemen.
I have a problem with my monitor. It turns off after a few seconds or flickers. Shining a flashlight on the screen doesn't show any image, so I guess it's not the "2 seconds to dark" I read in the forum.
To turn it back on, I have to press the power button twice. Then after a few seconds it turns off again or flickers. See video.
https://drive.google.com/file/d/1L6S...ew?usp=sharing
Things I tried
- Bought a new AC adapter thinking that was the problem but the problem... -
Looking through my repair pictures and notes, it's been a long time since I posted anything in the LCD monitors section. So here goes that.
I'm dedicating this thread to one of the very first LCD monitors I repaired (if not the first one), which was more than 10 years ago now. The monitor is a Wise Wing, model F199. It's a 19” CFL-backlit LCD. I got it for free off of Craigslist in 2009 from a guy, who said he bought it for cheap from Wallmart and the monitor worked only for a little less than 2 years before quitting.
When I saw the Craigslist post, I wasn't...
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