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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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I am trying to repair a vertical size and liniarity problem with a Viewsonic
E771. The picture only fills about 75% of the screen and is non linear. It is squishes and bows a bit toward the top of the picture. I have searched and searched in the vertical deflection circuits but have been unable to find a problem. I tested a lot of components and even replaced a few, but no luck. I do have a schematic. I can stretch it using the OSD controls, but that only fills about 75% of the screen. I'm know I'm not the first person to try to fix a problem like this. I find other reports on the internet of this same model with the same problem. But, I can't find and reports of what was done to fix it. Has anyone seen this before? Or can someone give me some more direction? Thanks. |
#2
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Use an ESR meter and check the capacitors in the vertical deflection
circuit. You may even need to pull them and check all the critical parameters to find the one that is bad, Value, ESR, leakage, etc. David "Scott Nielson" wrote in message ... I am trying to repair a vertical size and liniarity problem with a Viewsonic E771. The picture only fills about 75% of the screen and is non linear. It is squishes and bows a bit toward the top of the picture. I have searched and searched in the vertical deflection circuits but have been unable to find a problem. I tested a lot of components and even replaced a few, but no luck. I do have a schematic. I can stretch it using the OSD controls, but that only fills about 75% of the screen. I'm know I'm not the first person to try to fix a problem like this. I find other reports on the internet of this same model with the same problem. But, I can't find and reports of what was done to fix it. Has anyone seen this before? Or can someone give me some more direction? Thanks. |
#3
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![]() Scott Nielson wrote: I am trying to repair a vertical size and liniarity problem with a Viewsonic E771. The picture only fills about 75% of the screen and is non linear. It is squishes and bows a bit toward the top of the picture. I have searched and searched in the vertical deflection circuits but have been unable to find a problem. I tested a lot of components and even replaced a few, but no luck. I do have a schematic. I can stretch it using the OSD controls, but that only fills about 75% of the screen. I'm know I'm not the first person to try to fix a problem like this. I find other reports on the internet of this same model with the same problem. But, I can't find and reports of what was done to fix it. Has anyone seen this before? Or can someone give me some more direction? Thanks. To your question about has any else seen this problem befo The answer is "Yes!" I like you, had tried everything I could think of since this was the ONLY problem with the monitor. After more hours than I wish to admit to, I tore the monitor apart for parts so that I would stop going back to it with another idea. It became almost an obsession. I shall watch this thread to see if you find the problem. Good luck. |
#5
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![]() Asimov wrote: " bravely wrote to "All" (11 May 04 11:59:45) --- on the heady topic of " Viewsonic Vertical Problem" I had a monitor, I forget the brand, with a similar vertical problem at the top of the display, only to make it more interesting, this one was intermittant. Turned out to be a zener diode near the vertical IC which was opening up. Like you I had gone at it a few times and gave up in frustration but the diode stared out at me one time which then prompted me to drive it with an external current source to show a high resistance when the package was moved. Bugger that was it! Interesting!! I shall keep this in mind if I ever see such a problem again. Hopefully, I will NEVER see this type of problem again. us From: lid us Scott Nielson wrote: I am trying to repair a vertical size and liniarity problem with a Viewsonic E771. The picture only fills about 75% of the screen and is non linear. It is squishes and bows a bit toward the top of the picture. I have searched and searched in the vertical deflection circuits but have been unable to find a problem. I tested a lot of components and even replaced a few, but no luck. I do have a schematic. I can stretch it using the OSD controls, but that only fills about 75% of the screen. I'm know I'm not the first person to try to fix a problem like this. I find other reports on the internet of this same model with the same problem. But, I can't find and reports of what was done to fix it. Has anyone seen this before? Or can someone give me some more direction? Thanks. us To your question about has any else seen this problem befo The us answer is "Yes!" I like you, had tried everything I could think of us since this was the ONLY problem with the monitor. After more hours us than I wish to admit to, I tore the monitor apart for parts so that I us would stop going back to it with another idea. It became almost an us obsession. I shall watch this thread to see if you find the problem. us Good luck. ... You mean 15" sparks are SUPPOSED to come out of this thing?!? |
#6
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Well, I replaced almost everything in the vertical circuit and the vertical
problem didn't go away. So, we'll be replacing this montior with a new LCD monitor. wrote in message ... Asimov wrote: " bravely wrote to "All" (11 May 04 11:59:45) --- on the heady topic of " Viewsonic Vertical Problem" I had a monitor, I forget the brand, with a similar vertical problem at the top of the display, only to make it more interesting, this one was intermittant. Turned out to be a zener diode near the vertical IC which was opening up. Like you I had gone at it a few times and gave up in frustration but the diode stared out at me one time which then prompted me to drive it with an external current source to show a high resistance when the package was moved. Bugger that was it! Interesting!! I shall keep this in mind if I ever see such a problem again. Hopefully, I will NEVER see this type of problem again. us From: lid us Scott Nielson wrote: I am trying to repair a vertical size and liniarity problem with a Viewsonic E771. The picture only fills about 75% of the screen and is non linear. It is squishes and bows a bit toward the top of the picture. I have searched and searched in the vertical deflection circuits but have been unable to find a problem. I tested a lot of components and even replaced a few, but no luck. I do have a schematic. I can stretch it using the OSD controls, but that only fills about 75% of the screen. I'm know I'm not the first person to try to fix a problem like this. I find other reports on the internet of this same model with the same problem. But, I can't find and reports of what was done to fix it. Has anyone seen this before? Or can someone give me some more direction? Thanks. us To your question about has any else seen this problem befo The us answer is "Yes!" I like you, had tried everything I could think of us since this was the ONLY problem with the monitor. After more hours us than I wish to admit to, I tore the monitor apart for parts so that I us would stop going back to it with another idea. It became almost an us obsession. I shall watch this thread to see if you find the problem. us Good luck. ... You mean 15" sparks are SUPPOSED to come out of this thing?!? |
#7
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I've been monitoring this post for a few days, and wonder if it relates to
my problem. My ViewSonic E790, does something messed up. I contacted ViewSonic, and they said it was because it need more of a dedicated power source, because of the size of the monitor. What it does, is the screen shrinks. It's a 19" (18" viewable), that will shrink to about 15". The actually video, not the whole monitor.. ![]() around the whole video. You can even use the OSC and widen it back out. However, after it get's done "Throwing it's little Fit", and returns back to it's original size, you have to resize it back, or the screen is too big too see around the edges. The screen also gets really bright. Most of the time, it "flickers" like the above stated, for about 5-10 minutes, then returns to normal, and I don't have a problem for a while. Other times, it will do it for a couple hours at a time. AND on occasion, when it shrinks, it will turn off. But the green light will stay on like if the monitor is still active. (Normally the light turns orange, when it goes into stand by) Now, once again, I contacted ViewSonic when I first noticed this problem. The said it was because I had too much plugged into the outlet. So I ran a construction extension cord to an outlet that had nothing plugged into it (The whole circuit). It stopped for a while (about a month). However, it started again. But, guess what, it was out of warranty. Now, I moved over 700 miles from where I lived at, and still have the same problem. So I tend to think that it is in the monitor, ViewSonic was just tiring to get out of fixing it.... Thanks, Rick wrote in message ... Asimov wrote: " bravely wrote to "All" (11 May 04 11:59:45) --- on the heady topic of " Viewsonic Vertical Problem" I had a monitor, I forget the brand, with a similar vertical problem at the top of the display, only to make it more interesting, this one was intermittant. Turned out to be a zener diode near the vertical IC which was opening up. Like you I had gone at it a few times and gave up in frustration but the diode stared out at me one time which then prompted me to drive it with an external current source to show a high resistance when the package was moved. Bugger that was it! Interesting!! I shall keep this in mind if I ever see such a problem again. Hopefully, I will NEVER see this type of problem again. us From: lid us Scott Nielson wrote: I am trying to repair a vertical size and liniarity problem with a Viewsonic E771. The picture only fills about 75% of the screen and is non linear. It is squishes and bows a bit toward the top of the picture. I have searched and searched in the vertical deflection circuits but have been unable to find a problem. I tested a lot of components and even replaced a few, but no luck. I do have a schematic. I can stretch it using the OSD controls, but that only fills about 75% of the screen. I'm know I'm not the first person to try to fix a problem like this. I find other reports on the internet of this same model with the same problem. But, I can't find and reports of what was done to fix it. Has anyone seen this before? Or can someone give me some more direction? Thanks. us To your question about has any else seen this problem befo The us answer is "Yes!" I like you, had tried everything I could think of us since this was the ONLY problem with the monitor. After more hours us than I wish to admit to, I tore the monitor apart for parts so that I us would stop going back to it with another idea. It became almost an us obsession. I shall watch this thread to see if you find the problem. us Good luck. ... You mean 15" sparks are SUPPOSED to come out of this thing?!? |
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