Re: HP L1955 No Video
I was finally able to get some parts off of eBay.
Turns out that the LCD panel was bad. Once I replaced that it worked.
Now, given what happened to my old panel (fade to black from the sides to the center), is there a way to fix it? What would cause an LCD panel to fade to black from the sides inward?
conglo
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Last Activity: Today, 07:18 AM
Joined: 08-07-2009
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Re: HP L1955 No Video
I've found a datasheet for the Genesis gm2221 which is similar to the gm5321. I've attached it here in case anyone needs it. I've also attached a datasheet for the AU Optronics M190EN03 V0 LCD panel. This is the LCD panel in my L1955.
Now onto my findings...
Using the datasheet, I've checked most of the pins on the gm5321 and they all appear to be correct either 1.8V or 3.3V.
I haven't changed the caps on the logic board. Should this be done? I'm not sure if anyone has ever had a problem with those.
...Leave a comment:
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Re: PC Speakers Changing Volume
The sound isn't scratchy when I turn the pot.
Does this positively eliminate the pot?...Leave a comment:
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Re: HP L1955 No Video
The lamps are fine. I can see them turn on.
Basically, the monitor works correctly except that there is no video...see the post above this one for the details....Leave a comment:
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Re: HP L1955 No Video
The extra circuit board you're referring to is probably the USB board. This monitor has a built in USB hub.
I don't know if it helps, but I've noticed that there is almost no electrical whine noise anymore since I've changed the caps.
As for what is happening...
The backlights are on, but the screen is black. There is a faint vertical grey bar that is in the center of the screen. I think this is the message text from the monitor saying that there is no signal and then another one saying that it is going to...Last edited by conglo; 08-15-2009, 01:55 PM.Leave a comment:
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Re: HP L1955 No Video
I've changed all of the caps on the PSU/Inverter board, but nothing has changed.
What should I do now?Leave a comment:
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Re: PC Speakers Changing Volume
The audio source is good. I've tried with three different sound cards and they all do the same thing. Then, thinking it was my computer, I tried it with a portable MP3 player and I got the same results.
I figured it must be the speakers.Leave a comment:
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Re: PC Speakers Changing Volume
The cables feel pretty solid, but I may buy new ones.
As for the volume control...
There is a mechanical pot in it. I never use it though. Could it just "go bad" if it is untouched? Of course, I did touch it when I first noticed this problem.
One other thing that I think it could be...
I've unplugged the audio cable without first turning off the speakers and it made hums and pops. Would that break anything?
Thanks.Leave a comment:
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PC Speakers Changing Volume
I have a Cambridge Soundworks FPS2000 PC speaker system. It's a standard 4.0 + subwoofer setup.
Sometimes the volume changes. I can't reproduce it when I want; it randomly happens. It seems to be a drop in volume and them it will randomly go back up in volume at any later time.
The volume levels don't seem to change. The lower volume always sounds the same and when it goes back up, it sounds the same. So, the volume levels aren't random, but the amount of level drop seems to be consistent.
What would cause this? Bad Caps?
Do you think this is... -
Re: HP L1955 No Video
Thank you!
Is there any reason for not replacing the 450V cap?...Leave a comment:
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Re: HP L1955 No Video
Here is a list of electrolytic caps from my PSU/Inverter board...
[CODE]PCB# Brand Volts Farads Diameter Height
---- ----- ----- ------ -------- ------
C802 Elite 35V 220uF 8mm 16mm
C801 Elite 35V 220uF 8mm 16mm
C605 Elite 450V 150uF 17mm 50mm
C813 Lelon 50V 33uF 6mm 11mm
C811 Jamicon 50V 1uF 5mm 11mm
C611 Lelon 50V 47uF 6mm 11mm
C606 Lelon 50V 47uF 6mm 11mm
C707 Elite 16V 1000uF 10mm 21mm
C712 Elite 16V 1000uF 10mm 21mm
C703 Elite 35V 470uF 10mm 21mm
...Leave a comment:
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Re: HP L1955 No Video
Which caps are the secondary filters? Do you know what the voltages should be?...Leave a comment:
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Re: HP L1955 No Video
I've tested some caps (without removing them from the board) and they don't read the correct values. Since I didn't remove them, I'm not sure that my readings are ok or not.
Is it ok to test while still on the board?
Also, since it shouldn't cost to much to replace the caps...
What should I buy for replacements?
I can list the caps currently on the boards if needed.
Thanks.Leave a comment:
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Re: HP L1955 No Video
Here are pictures of my inverter board (front and back) and my video board.
I've included a couple of shots in different lighting....Leave a comment:
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Re: HP L1955 No Video
The voltages to the video board are 1V, 3V, and some 5V. Does that sound right?
I'll also post a pic of the board if you'd like...I'm currently charging my camera batteries....Leave a comment:
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Re: HP L1955 No Video
I have those caps on my board, but they don't look like they are bad (visual inspection only).
Those caps are on the inverter board. Would they cause the no video problem? I figured it would have to be on the video board. But, of course, the video board looks very good to me.
Do you know what the replacement parts would be for the inverter board?Leave a comment:
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HP L1955 No Video
I have a HP L1955 with a BenQ 48.L1A02.A31 board in it.
I was using the monitor and it faded to black from the edges to the center...kind of like the circle wipes that you see in the movies.
The weird thing is that the backlights are still on and the indicator lamp is green, but I don't have any video. The only thing that I can see is a faint gray vertical bar on the center of the screen. The bar is about 1/3 the size of the screen and extends all the way from the top to the bottom of the screen.
This happens even without a PC connected to the monitor....
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