Very poorly Yusmart 2291p-p
Hello everyone, new forum user so please be gentle. The problem is my faulty monitor. Upon turning on, a grey screen fades to black with red, green and blue vertical pinstripes. Some of the electrolytics on the main board did make me wonder, but I haven't changed or tested them yet. Thought I'd hear from you guys first. Wondering where to begin. Cheers in advance, Lee.
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Re: Very poorly Yusmart 2291p-p
Post clear focused pictures AFTER reading
https://www.badcaps.net/forum/showthread.php?t=1868
Please do not post pictures inline.
Take your boards to a window on a sunny day, turn flash off, and use macro mode. Take a top down view of all your boards (front and back). Make sure the photo is legible so that we can read the PCB printing clearly. A shutter speed of 1/125 or faster will produce nice clear focus pictures. Try to get a photo that is 2000x2000 resolution or as close as possible.
Here is an example of the pictures we want.
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If you are new to this forum, we can help a lot more if you please post clear focused pictures (max resolution 2000x2000 and 2MB) of your boards using the manage attachments button so they are hosted here. Information and picture clarity compositions should look like this post.
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Re: Very poorly Yusmart 2291p-p
Sorry, was going to do that
Shall crack on with it now.
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Re: Very poorly Yusmart 2291p-p
Hello all, board pictures now uploaded (had to wait for daylight) I've been looking at your badcap list, these boards contain both Hermei & Lelon caps, but they aren't bulging or leaking. Cheers, Lee.Attached FilesComment
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Re: Very poorly Yusmart 2291p-p
Welcome to the forum! Funny, but there's another member that posted problems with their Yusmart. Although their problems are different from yours, it's worth reading:
https://www.badcaps.net/forum/showth...hlight=yusmart
Please post a photo of what the screen looks like with the vertical lines, etc.
You can probably start by checking for proper voltages at the power supply. Measure the output voltages at the 9 pin connector cable (P802) at the right side of your first photo.Last edited by jetadm123; 09-13-2010, 07:47 AM.Comment
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Re: Very poorly Yusmart 2291p-p
Also check the voltage regulator (I104) outputs located on your logic card (3rd photo). Pin 1 is ground, Pin 2 = 3.3V and Pin 3 = 5V.Comment
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Re: Very poorly Yusmart 2291p-p
Hello again, thanks for the welcome.
I've been measuring and here are some findings :
I104 has 3.29 and 4.66V from pins 2 & 3 respectively.
C805 ( the big one) has +161-3V on the anode & -154-6V at the cathode and also the end cap.
My P802 (9 pin connector) voltages are pretty much the same as fusionmax in the other thread, however mine are 4.99V compared to his 5.15V on the same pins (2,5 & 6). I get pin 7 reading 1.62V & pin 8 reads 2.83V all other pins read zero (1,3,4,9)Attached FilesComment
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Re: Very poorly Yusmart 2291p-p
Output of I104 looks pretty good.
Please note that I'm referencing a schematic from a Viewsonic monitor as provided by fusionmax.
5V output vs 4.99V is good.
C805 Voltage is good.
Pin 7 controls brightness.
Pin 8 is on/off
24V output is probably good, since the backlights are coming on.
Unfortunately, nothing is sticking out at this point.
Looking at the photos of the vertical lines: Are the same lines present everytime you turn on the monitor? Or are they random?
I suspect you already reseated the cable connecting the logic card to the LCD panel, since you had to piece everything back together to take the photos.
With the vertical lines showing, have you tried GENTLY tried pressing on the LCD screen at the top most point of one of those vertical lines to see if it goes away? Just checking to see if there's a loose connection.
If there was also a picture with the vertical lines, I would say it was the LCD panel that had failed, but what's got me puzzled is the lack of a picture. Bad logic card?Last edited by jetadm123; 09-13-2010, 08:42 PM.Comment
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Re: Very poorly Yusmart 2291p-p
If you get no respite with jetadm123's suggestion,then there is no other option but to try a replacement Logic board to confirm Logic or LCD Panel,but I'm sure you would have done that,if you had one.Chances are that it is the Panel.Comment
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Re: Very poorly Yusmart 2291p-p
Hello,
I've managed to acquire another logic board, shall have it tomorrow hopefully. Will keep you updated. Cheers, Lee.Comment
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If you are new to this forum, we can help a lot more if you please post clear focused pictures (max resolution 2000x2000 and 2MB) of your boards using the manage attachments button so they are hosted here. Information and picture clarity compositions should look like this post.
We respectfully ask that you make some time and effort to read some of the guides available for basic troubleshooting. After you have read through them, then ask clarification questions or report your findings.
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Re: Very poorly Yusmart 2291p-p
Yes, hopefully. I'm also currently looking at building an ESR meter, which should assist in my task. I've been reading some of the threads on here about them. If I had the money I'd just buy one, but needs must & all that.
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Re: Very poorly Yusmart 2291p-p
Hi,
I have the exact same monitor and have been having problems with it, mine is totally dead though, see post at https://www.badcaps.net/forum/showthread.php?t=11024
I was wondering if you could do me a favour and measure the voltage you are getting at the power button?
I want to rule it out as an issue on mine and have been unable to find a datasheet to give me any more info.
Also, where did you manage to find a replacement logic board?Comment
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Re: Very poorly Yusmart 2291p-p
Have you cleaned and refitted the screen cable?Comment
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Hi it looks like everything works don't know where to test except the 390v in the 2 capacitor in the hot side of the power supply and the weird 180v in the diodes in the cold side that should be discharged it is writin on the circuit no more you can read what is written on the circuit quite srrange color mixiing yellow and white
anyhow i couldn't t read anything else
the backlight is on strong and the screen does not get dark or very dark but no pictures
the mainborad feels a bit hott on the black part i test it to 52 degree's against 34 to 40 on the rest of it
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