Screen turns Red, hor. lines can be seen


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Screen turns Red, hor. lines can be seen

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Evander
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May 27, 2005, 4:45 AM

Post #1 of 5 (1104 views)
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Screen turns Red, hor. lines can be seen	Can't Post

Hello, I've got a Sony Trinitron from '95, recently the screen randomly turns red with the lines, it may fix itself momentarily or stay stuck like that for awhile- sometimes it may shut itself off in this condition.

Tried disconnecting and reconnecting various cables, but didn't help. I did notice that if I push the square circuit board on the back of the tube forward (with the rubber end of a screwdriver), the screen turns normal. Pushing it backwards has no effect. But doing that everytime I get a red screen is a stopgap solution at best. Hope someone has a not-too-complicated way to fix this. Otherwise I may have to go real low-tech and try attaching a string or weighted object to always make this board push forward (assuming that would work...)

Also I can take a picture of this condition if anyone thinks it'll help

kuhurdler
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May 27, 2005, 1:12 PM

Post #2 of 5 (1098 views)
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Re: [Evander] Screen turns Red, hor. lines can be seen [In reply to]	Can't Post

you need to take a soldering iron and solder whatever component is causing this. You already narrowed it down somewhat. when it happens again, Poke around with a wooden stick to figure out exactly where the solder point is that is cracked.

-RiddledTV.com
http://www.riddledtv.com/forums/

shadetree
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May 27, 2005, 4:12 PM

Post #3 of 5 (1092 views)
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Re: [Evander] Screen turns Red, hor. lines can be seen [In reply to]	Can't Post

tap on neck of picture tube with screwdriver handle may be shorted tube

mel
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May 28, 2005, 12:29 AM

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Re: [Evander] Screen turns Red, hor. lines can be seen [In reply to]	Can't Post

Take a magnifying glass and carefully inspect the solder joints. A model number would have helped but it will probably be somewhere around R712 and Q711/112. Touch up any that even look questionable. If you don't find any bad joints, it is probably an intermittent internal short in the CRT as Shadetree suggests. If the CRT is shorted, post back with the model number and I'll give you a way to work around the short.

Electro
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May 30, 2005, 7:14 PM

Post #5 of 5 (1052 views)
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Re: [mel] Screen turns Red, hor. lines can be seen [In reply to]	Can't Post

Most probably, the board behind your picture tube has a loose socket. Turn off the power. Try pulling it off (carefully) and plugging the board back in, several times. This usually solves the problem. If excessive arching occurred, you may have to scrape the leads on your picture tube clean (use a fine grain sandpaper) before plugging the board back in.

If this doesn't work, then it could be a loose solder joint. reheat the electrical joints of the socket with a soldering iron. If you have to add solder, clean off the excess rosin with a quick brush of thinner. Let dry, and test again.

Logic is, since it's temporarily solved by pressure applied on the board, it's a loose connection problem on that part. Don't tweak on the variable resistors. You may not be able to return it to it's peak color mix.

Gud luck Smile

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