Does anybody know about tv's?

[Wrecked944]

Okay, I recently got an older projection TV. It has three CRT guns and has a 46" screen. At first, I got it on a lark. But now I am really starting to dig the big screen. It looks frickin' awesome (especially for F1 races). However, it has started to exhibit some odd behavior. Every now and then, the picture will distort severely. It looks as though the tuner is set "between" stations or maybe the vert or horizontal hold is out of whack. And I am sure it isn't caused by the mirror or anything like that because I can pull up the tv's internal menus and they appear perfect.

Now, the weird part is that I can often temporarily "fix" the problem by switching channels or turning the power off/on or switching from antenna to aux input or a host of other seemingly unrelated "changes". And yet, none of these "changes" works every time. Sometimes flipping the channel will "fix" it. Sometimes switching the input source a few times will "fix" it. It seems to follow no pattern.

So does anyone know enough about tv's to offer a guess as to what is happening? Or if it is unrepairable, is there a way I can just gut the internal electronics and run the CRT's off of another tv or another "motherboard"?

[Scott R]

Originally posted by JanusCole
Okay, I recently got an older projection TV. It has three CRT guns and has a 46" screen. At first, I got it on a lark. But now I am really starting to dig the big screen. It looks frickin' awesome (especially for F1 races). However, it has started to exhibit some odd behavior. Every now and then, the picture will distort severely. It looks as though the tuner is set "between" stations or maybe the vert or horizontal hold is out of whack. And I am sure it isn't caused by the mirror or anything like that because I can pull up the tv's internal menus and they appear perfect.

Now, the weird part is that I can often temporarily "fix" the problem by switching channels or turning the power off/on or switching from antenna to aux input or a host of other seemingly unrelated "changes". And yet, none of these "changes" works every time. Sometimes flipping the channel will "fix" it. Sometimes switching the input source a few times will "fix" it. It seems to follow no pattern.

So does anyone know enough about tv's to offer a guess as to what is happening? Or if it is unrepairable, is there a way I can just gut the internal electronics and run the CRT's off of another tv or another "motherboard"?

If it's a Mitsubishi then I would check the convergence circuit, they overheat and break the solder traces. The good thing is it's an easy fix to remove the tuner board and redo the solder joints.

[TerryH]

Isn't this the tv that bounced down a flight a stairs? You might have several solder problems.

[Wrecked944]

Originally posted by TerryH
Isn't this the tv that bounced down a flight a stairs? You might have several solder problems.

YES it is! Solder joint problems came to mind right away because of the way it tumbled down the stairs...but the way it "fixes" itself with seemingly random actions has me utterly baffled. I just spoke to a buddy who is an electronics guru and he thinks it may be heat related and that the momentary voltage changes brought on by channel switching and other stuff may help explain the temporary "fixing". I may pull off the back panel tonight and set up a fan to keep it cool.

[Scott R]

Originally posted by JanusCole
YES it is! Solder joint problems came to mind right away because of the way it tumbled down the stairs...but the way it "fixes" itself with seemingly random actions has me utterly baffled. I just spoke to a buddy who is an electronics guru and he thinks it may be heat related and that the momentary voltage changes brought on by channel switching and other stuff may help explain the temporary "fixing". I may pull off the back panel tonight and set up a fan to keep it cool.

Your buddy is dead on, you'll probably never get it cooled enough to keep it from blanking out. Just pull the boards (carefully to avoid electrical shock) and inspect all of the solder joints with freon or a magnifying glass. It should be easy to spot the bad ones.

[Wrecked944]

SCORE!! I took my buddies advice and did some "percussive" analysis. Basically, I pulled off the back panel and started (carefully!) tapping electronic bits until I saw an effect on the screen. I eventually narrowed it down to an internal cable. It turns out the connector was corroded. So after twisting it around a few times to grind off the goop, the TV display was perfect and no amount of abuse could make it malfunction. WOO HOO! Thanks for your advice, guys!

So now I am watching the Rolex race at Watkins Glen and it looks the f*cking balls!

[Joeaksa]

You might drop it UP the stairs. Might un-do some of the issues!

[kaisen]

If only we could 'fix' Tabs after his tumble down the stairs....

[Joeaksa]

Originally posted by kaisen
If only we could 'fix' Tabs after his tumble down the stairs....

We could but then he would be like Paris Hilton and no where near as personable...