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Wierd colours on my TV?

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Ash Small

Wed Jan 11 2012, 09:31PM

Registered Member #3414 Joined: Sun Nov 14 2010, 05:05PM
Location: UK
Posts: 4245

I've just moved house over christmas (Which is why I've not been on here much) and in the process, my 32 inch Sony Trinitron TV got dropped.

It now has a green patch in the lower right corner and a blue patch in the lower left.

Is there anythingt I can do about this? (I assume it is a result of it being dropped)

Should I just buy another on Ebay? (It only cost me Â£30, and I assume it has a fairly large flyback inside.)

Ben Solon

Wed Jan 11 2012, 10:13PM

Registered Member #3900 Joined: Thu May 19 2011, 08:28PM
Location:
Posts: 600

dropping a CRT can cause A LOT of things to go wrong... coils bumped out of place, damages to the vacuum tube, etc. i would open it up and look if anything is noticeably wrong. if not you can still find the problem but with much greater difficulty. it really depends on your electronics experience. if you have little, than take it to a local repairman, or rip it apart for parts(flyback transformers are nice!). that's really all someone can say, because as i said, CRT's are fragile, and lots of things can go wrong. more so than solid-state stuff.

Mark-H

Wed Jan 11 2012, 10:27PM

Registered Member #607 Joined: Tue Mar 27 2007, 10:39AM
Location:
Posts: 64

You could try moving the scanning coils on the tube neck. I doubt it's the problem. Is the picture slightly skewed or changed in size?
The ion trap magnets may have shifted. They can be a pig to align.
The worst case is the shadowmask may have moved in the tube. That's pretty much the end of it if it has.
Have you tried degaussing it? When you turn on, do you get that loud buzz/thump as the built in degaussing coils energise?

I'm not a qualified TV engineer, so all of the above may be bunkum. But as a tinkerer, the ion trap may be your best bet.

Alex M

Wed Jan 11 2012, 10:36PM

Registered Member #3943 Joined: Sun Jun 12 2011, 05:24PM
Location: The Shire, UK
Posts: 552

Is there an option to degauss coil the CRT in the menus?

testtest

Wed Jan 11 2012, 11:09PM

Registered Member #3271 Joined: Mon Oct 04 2010, 02:29AM
Location: Canada
Posts: 159

Serviced a lot of these in the past.
Before opening anything degaus the tube with an external coil (inside degaus coil on stratup is just for maintenance and not that strong). Once the outside degaus coil is activated scan in a circular motion while slowly moving away to about two meters. Do not stay at one spot or too close. See if the purity gets better. If so repeat. If not , was the TV subjected to a strong magnetic field? Finally a shock could have dislodged one of the many small magnets glued on the CRT back glass. These are for corner correction mostly. It will be visible from the glue trace on the glass and loose in the insides. The deflection yoke assembly could have been displaced. Easy to realign, but you need the right tools. Get a Sony service person for that unless you have the service manual and the tools. Many Sonys can be put in a service mode to get the right patterns and pure colour screens but you need the manual to navigate through the program. There is also the possibility of a bad contact on one of the convergence/landing board from the shock. In some models they are on the CRT pins and on the mother board in a socket. The one on the CRT neck is bulky and usually held with a spot of glue. The glue ages and looses its holding property. I have seen a few cases where a shock dislodged them. Is your convergence OK in the affected area or is it just a colour purity issue? Final, but improbable thought, is the shadow mask that is distorted. Only saw one case of those in 30 years.

Dr. Dark Current

Thu Jan 12 2012, 11:03AM

Registered Member #152 Joined: Sun Feb 12 2006, 03:36PM
Location: Czech Rep.
Posts: 3384

Maybe the shadow mask wires got bent, in this case there's nothing you can do about that...

radiotech

Fri Jan 13 2012, 06:49AM

Registered Member #2463 Joined: Wed Nov 11 2009, 03:49AM
Location:
Posts: 1546

Apart from the screen color blotches, is the image entirely satisfactory?

Patrick

Fri Jan 13 2012, 06:55AM

Registered Member #2431 Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639

Dr. Dark Current wrote ...

Maybe the shadow mask wires got bent, in this case there's nothing you can do about that...

arnt the sony trinitron's known to have two or more horizontal special wires, that other makers dont use?

I think his CRT is fine to continue using, albeit in this lame condidtion....

johnhalrey

Fri Jan 13 2012, 12:41PM

Registered Member #4333 Joined: Fri Jan 13 2012, 12:35PM
Location:
Posts: 1

I guess you need to replace your Tv screen. I am of the opinion that patches appear due to breaking of screen.Hopefully your issue will be resolved in this way.

PSCG

Fri Jan 13 2012, 12:50PM

Registered Member #3792 Joined: Sun Mar 27 2011, 06:07PM
Location:
Posts: 136

As seen from Wiki, Trinitron technology is a bit different than the normal CRT technology. It has a single cathode (instead of three separate) and the most important, a vertical aligned grid (normal CRT's have a grid that has many small holes).

Maybe, some of the the vertical pieces of the grid have been moved from their normal position and this causes the electron beams to illuminate irregularly the screen phosphors.

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