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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
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#1
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Samsung TFT 204b: extreme slow response
Dear all,
My Samsung 204B has a *very* long response time, black-white several secs.. white-black ~0.5 sec. This happened instantly while in operation, and persists ever since. Happens both on DVI and VGA, with different graphic cards (NVIDIA GF 7600GS and ATI 7500) as well as without any signal input at all, then showing the wandering "Check signal cable" window. I opened the case, the caps look OK to me, no bulging or leaking. Here's a video showing the slow response. The graphics should be updated instantly. Instead, it appears more like a fade-in http://www.youtube.com/watch?v=8tcwLBV3jxs Any hints are greatly appreciated. Thomas |
#2
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Samsung TFT 204b: extreme slow response
On Tue, 13 Apr 2010 02:01:11 -0700 (PDT), thomas albrecht
wrote: Dear all, My Samsung 204B has a *very* long response time, black-white several secs.. white-black ~0.5 sec. This happened instantly while in operation, and persists ever since. Happens both on DVI and VGA, with different graphic cards (NVIDIA GF 7600GS and ATI 7500) as well as without any signal input at all, then showing the wandering "Check signal cable" window. I opened the case, the caps look OK to me, no bulging or leaking. Here's a video showing the slow response. The graphics should be updated instantly. Instead, it appears more like a fade-in http://www.youtube.com/watch?v=8tcwLBV3jxs Any hints are greatly appreciated. Thomas Did you try a different monitor to eliminate any possibility it is GUI effects from Winders? |
#3
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Samsung TFT 204b: extreme slow response
On Apr 13, 11:01*am, thomas albrecht
wrote: Dear all, My Samsung 204B has a *very* long response time, black-white several secs.. white-black ~0.5 sec. This happened instantly while in operation, and persists ever since. Happens both on DVI and VGA, with different graphic cards (NVIDIA GF 7600GS and ATI 7500) as well as without any signal input at all, then showing the wandering "Check signal cable" window. I opened the case, the caps look OK to me, no bulging or leaking. Here's a video showing the slow response. The graphics should be updated instantly. Instead, it appears more like a fade-inhttp://www.youtube.com/watch?v=8tcwLBV3jxs Any hints are greatly appreciated. Thomas Does the same happen once you are logged in? Did you try the monitor on another computer (i.e. e.g. without GRUB)? |
#4
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Samsung TFT 204b: extreme slow response
Thank you for your replies!
Does the same happen once you are logged in? Did you try the monitor on another computer (i.e. e.g. without GRUB)? Yes, same effect during POST, OS booting, logged in (text mode), and GUI running. Connecting the faulty monitor to another machine did not help. Did you try a different monitor to eliminate any possibility it is GUI effects from Winders? If I connect another monitor to my primary machine, everything shows up fine, so it's definitely a problem with the monitor itself. |
#5
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Samsung TFT 204b: extreme slow response
On Apr 13, 4:32*pm, thomas albrecht wrote:
Connecting the faulty monitor to another machine did not help. Why? If it still shows as faulty if you connect it to another machine, it is clearly a monitor problem. |
#6
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Samsung TFT 204b: extreme slow response
Connecting the faulty monitor to another machine did not help.
Why? If it still shows as faulty if you connect it to another machine, it is clearly a monitor problem. Of course you're right. I just wanted to express that my problem with this monitor persists, even when I connect it to another machine. So it's not a problem with that specific machine or graphics card or such. |
#7
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Samsung TFT 204b: extreme slow response
Why? If it still shows as faulty if you connect it to another machine,
it is clearly a monitor problem. And I didn't mean to say your post wouldn't be helpful, of course! |
#8
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Samsung TFT 204b: extreme slow response
On Apr 13, 4:58*pm, thomas albrecht wrote:
Why? If it still shows as faulty if you connect it to another machine, it is clearly a monitor problem. And I didn't mean to say your post wouldn't be helpful, of course! No problem, Thomas. I was tired ;-). Trying William's suggestion does no harm, and that could be tried. In such situations, anything needs to be tried, particularly the obvious. Habitually, TFTs monitors do or do not work. I mean... you turn them on, and either everything's right or nothing works. That is my point of view, but I am not the only one to preach in this. |
#9
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Samsung TFT 204b: extreme slow response
Hi!
It sounds like a signal processing problem. While I doubt that it will help, have you tried just unplugging the monitor from power and letting it sit for a while? Anywhere from several hours to overnight would do. It doesn't cost anything to try... William |
#10
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Samsung TFT 204b: extreme slow response
Hi William!
have you tried just unplugging the monitor from power and letting it sit for a while? Thanks for your suggestion! Actually, it has been sitting powered off & disconnected for several months after it broke. I only recently leaned about the many problems with bulging capacitors of this particular TFT, so I decided to give it a try and look inside. The youtube video, however, I took just the other day, so, unfortunately, this seems to be more like a long-term problem... Thomas |
#11
Posted to sci.electronics.repair
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Samsung TFT 204b: extreme slow response
Hi William!
have you tried just unplugging the monitor from power and letting it sit for a while? Thanks for your suggestion! Actually, it has been sitting powered off & disconnected for several months after it broke. I only recently leaned about the many problems with bulging capacitors of this particular TFT, so I decided to give it a try and look inside. The youtube video, however, I took just the other day, so, unfortunately, this seems to be more like a long-term problem... Thomas |
#12
Posted to sci.electronics.repair
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Samsung TFT 204b: extreme slow response
Hi William!
have you tried just unplugging the monitor from power and letting it sit for a while? Thanks for your suggestion! Actually, it has been sitting powered off & disconnected for several months after it broke. I only recently leaned about the many problems with bulging capacitors of this particular TFT, so I decided to give it a try and look inside. The youtube video, however, I took just the other day, so, unfortunately, this seems to be more like a long-term problem... Thomas |
#13
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Samsung TFT 204b: extreme slow response
On 13 Abr, 11:01, thomas albrecht wrote:
Dear all, My Samsung 204B has a *very* long response time, black-white several secs.. white-black ~0.5 sec. This happened instantly while in operation, and persists ever since. Happens both on DVI and VGA, with different graphic cards (NVIDIA GF 7600GS and ATI 7500) as well as without any signal input at all, then showing the wandering "Check signal cable" window. I opened the case, the caps look OK to me, no bulging or leaking. Here's a video showing the slow response. The graphics should be updated instantly. Instead, it appears more like a fade-inhttp://www.youtube.com/watch?v=8tcwLBV3jxs Any hints are greatly appreciated. Thomas This fade looks so nice it seems a feature instead of a fault. Have you checked all menu options to ensure some weird option has not been enabled? Carefully observing the video reveals that going from white to black is immediate but the opposite is not. The effect reminds me of a digital clock with weak battery. It could be some weak voltage from the power supply, probably a bad capacitor. |
#14
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Samsung TFT 204b: extreme slow response
Hi Jeroni!
This fade looks so nice it seems a feature instead of a fault. Have you checked all menu options to ensure some weird option has not been enabled? So maybe I should sell this monitor for it has this extremely rare, special feature? Nope, unfortunately, there are no menu options like that... It could be some weak voltage from the power supply, probably a bad capacitor. OK, thanks for the hint. That model is known for having problems with capacitors, but commonly described symptoms are different from what I observe. I'm going to change the capacitors, anyway, and keep you posted. Thomas |
#15
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Samsung TFT 204b: extreme slow response
On Tue, 13 Apr 2010 02:01:11 -0700 (PDT), thomas albrecht
wrote: Dear all, My Samsung 204B has a *very* long response time, black-white several secs.. white-black ~0.5 sec. This happened instantly while in operation, and persists ever since. Happens both on DVI and VGA, with different graphic cards (NVIDIA GF 7600GS and ATI 7500) as well as without any signal input at all, then showing the wandering "Check signal cable" window. I opened the case, the caps look OK to me, no bulging or leaking. Here's a video showing the slow response. The graphics should be updated instantly. Instead, it appears more like a fade-in http://www.youtube.com/watch?v=8tcwLBV3jxs Any hints are greatly appreciated. Thomas While it isn't obvious, an LCD monitor breaks down into several electronic sections. Power supply, inverter / backlight, logic (signal processing) card, and LCD panel. 1. Check the output voltages of the power supply. Yes, I know the caps look good, but a quick check of the actual voltages MIGHT pickup a problem. 2. The logic card contains several voltage regulators to provide the proper voltages for the processor and it's support components, and often for the LCD panel. These are tyoically a three pin device with tab. Byu Googling the part number on these devices you can determine the output voltage. Verify those voltages. While it is unlikely an incorrect output voltage would cause the symptoms you describe, it's worth the try. 3. The LCD panel usually contains an electronics card (often conceled under a metal cover) which generates the voltages and signals necessary for the proper operation of the panel. I suspect one of these voltages is missing. This is going to require a LOT of detective work to analyse, so try the easier stuff first. PlainBill |
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