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The end of a PB170 LCD?
- Thread starter IIfx
- Start date
RIP, PB170.
But at least now you have parts for the other one.
But at least now you have parts for the other one.
i just got a 160 from another member here with similar screen issues, and the contrast would drift around as the screen warmed up.
I fixed it. works like a brand new screen too. There was a thread that i made a couple posts in about the same screen issues, and yellow corners, etc and i brought this up. but no one has tried or posted of trying of what i suggested. So i got a powerbook for myself, and tried it myself.
There is approximately a 40V or so supply that provides power to the STN grid itself. when the buffers/drivers scan the display, it sends AC current to each pixel twisting the crystal in one position or another, uses this supply as the B+ source for doing the "twisting"
problem is, this supply gets noisy and lowers in voltage, allowing the screen to do strange things. All the surface mount electrolytics were bad, just as the ones that plague compact macs. I replaced all of these and the screen worked like brand new.
I fixed it. works like a brand new screen too. There was a thread that i made a couple posts in about the same screen issues, and yellow corners, etc and i brought this up. but no one has tried or posted of trying of what i suggested. So i got a powerbook for myself, and tried it myself.
There is approximately a 40V or so supply that provides power to the STN grid itself. when the buffers/drivers scan the display, it sends AC current to each pixel twisting the crystal in one position or another, uses this supply as the B+ source for doing the "twisting"
problem is, this supply gets noisy and lowers in voltage, allowing the screen to do strange things. All the surface mount electrolytics were bad, just as the ones that plague compact macs. I replaced all of these and the screen worked like brand new.
Now this could be useful information. Where were these capacitors located? On the boards located within the screen assembly itself?
I will take pics when i get a new camera. My trust old Sony DSC-V1 that i used for everything took a shit. It turns on and right back off. strange. If i keep fiddling with it, i can get it to power on to lines in the LCD screen before it shuts back off. MADE IN CHINA.
Anyway, The LCD assembly itself has a DC-DC converter plus the connectors and everything else. it has SMD electrolytics.
When I get another camera, i will do a whole new thread on it. If thats ok.
Cap list:
Qty. 9 3.3uf 35V
1 22uf 35v
1 100uf 6v
You must use SMD electrolytics as replacements, or tants. regular radial patch-ins wont work, there is no space clearance to allow for this.
Anyway, The LCD assembly itself has a DC-DC converter plus the connectors and everything else. it has SMD electrolytics.
When I get another camera, i will do a whole new thread on it. If thats ok.
Cap list:
Qty. 9 3.3uf 35V
1 22uf 35v
1 100uf 6v
You must use SMD electrolytics as replacements, or tants. regular radial patch-ins wont work, there is no space clearance to allow for this.
It would be interesting to see the effect of capacitor replacement on a blackened screen....
I just fixed my trusty old sony DSC-V1. I took it apart and found a couple of bad electrolytics in the DC-DC converter. I wasnt out anything, so i stuck a couple more in and it worked. HA....
So when i get some time ill do some full documentation and pics. because i have 2 more screens to do. no worries.
So when i get some time ill do some full documentation and pics. because i have 2 more screens to do. no worries.
shit i totally forgot. LOL.
I have another LCD i have to do, so it would be easier if i just made a video.
I have another LCD i have to do, so it would be easier if i just made a video.
my guess it has a bad CCFL tube.
Just to clarify...
On LCD displays which stop displaying around the edges -- they kind of look like something has been nibbling the display around the edges, replacing the SM electrolytic caps inside the display restored them to full functionality?
I have some IBM 18.3" LCD displays from 2000 and a few of them are look like something dissolved/washed away the outer rim of the display when I try to use full resolution. So instead of 1280 X 1024 I must run them at 1024 X 768 to avoid the bad area.
Yes, I prefer a 1280 X 1024 display with pixels in a WYSIWYG size, to the modern wide screen, everything so small you must have the eyes of a twelve-year-old to see it screens.
Also, while these old IBM screens aren't terribly fast by modern standards, the evenness of the display is amazing. Newer displays (at least, the ones in my price range) seem to all have brighter and darker areas, but these old IBM displays are dead even in terms of brightness across the display.
They could stand to be brighter though. I'm guessing that the backlight tubes are down to 70 - 80% of their original output or some such too.
On LCD displays which stop displaying around the edges -- they kind of look like something has been nibbling the display around the edges, replacing the SM electrolytic caps inside the display restored them to full functionality?
I have some IBM 18.3" LCD displays from 2000 and a few of them are look like something dissolved/washed away the outer rim of the display when I try to use full resolution. So instead of 1280 X 1024 I must run them at 1024 X 768 to avoid the bad area.
Yes, I prefer a 1280 X 1024 display with pixels in a WYSIWYG size, to the modern wide screen, everything so small you must have the eyes of a twelve-year-old to see it screens.
Also, while these old IBM screens aren't terribly fast by modern standards, the evenness of the display is amazing. Newer displays (at least, the ones in my price range) seem to all have brighter and darker areas, but these old IBM displays are dead even in terms of brightness across the display.
They could stand to be brighter though. I'm guessing that the backlight tubes are down to 70 - 80% of their original output or some such too.
No.... I never had the "tunnel vision" What I had was a dark screen that the contrast adjustment would not restore, barely enough to see, but not enough to use, but it did exempt tunnel vision like symptoms. but that was because the contrast was too low i think.
Recapping the panel restored full contrast/brightness evenly across the screen.
Well, if the LCD was fast enough, but its no where near fast enough, but if it was....Trag, we need cap kits and colour LED backlight kits. It would be cool to have different colours.Replace the inverter just for giggles too.
you could use RGB backlight to do field-sequential color and it would appear that the mac would have full color. But the Video adapter doesnt support it, and neither does the LCD response time.
I did this very thing with an old Mac SE CRT and a color-wheel. built a full RGB color field-sequential VGA monitor. Same rule would apply with LCD, if you used RGB backlight instead of a color-wheel.
But the LCD response time isnt fast enough to be able to switch RGB video signaling without extreme flicker.
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