2nd Hand monitor Question

[Teebor]

I have just acquired a rather large Hantarex monitor for my upcoming MAME project.  Before I bought it I knew there was some slight discolouration but I figured I could degauss a few times to clear it.

I transported the screen over quite a distance (2 hours travel time) and when I got home I found the discoloration had moved but was also now worse.

The screen is very discoloured in the top right and bottom left corners and the longer I use it the patch slowly grows across the screen.  Degaussing doesn't fix the worst of it in the top corner but it does stop the "creep" for a sort while.  If I put a small magnet near that corner of the screen it returns to normal colouring.

Is there anything I can do to this myself to try and cure it? or will I just be making it worse?
Or is my only choice to go to the TV shop round the corner and get it professionally degaussed (well worth it as the price was very good)

Thanks

T

[dabone]

Did the yoke become loose?

Discoloration in the corners can mean that the yoke has moved a little during transport. With the monitor off see if it's loose.


Later,
dabone

[Teebor]

I am kinda new to monitors (but not electronics)

By the yoke you mean the metal frame used to mount the screen?

Sorry I should have mentioned that the screen is completely encased as its designed for display purposes, possibly video wall but the casing looks too big for that (I know a lot of hantarex screens are video wall screens so thats a guess)

I should have read the monitor faq before bothering you guys, I might try the magnet thing to fix it the damage can be reversed professionally hopefully anyway right?

[Nipedley]

The yoke is the big mass of copper winding on the neck of the tube just before the neckboard

[Teebor]

I know exactly which bit you mean now.  I will try and take a look at it later on tonight.

[Teebor]

I tried going near the screen with a small ring magnet this evening and it clears the picture whilst I am making spiral type patterns across the screen.  HOWEVER as soon as I stop the two corners return almost instantly (but perhaps a little less severe, I could be fooling myself though)  But I did notice that I was getting shocks from the magnet so I stopped after a while.

I tried switching the screen off, then on, letting it cool then on and off again a few times (until I got bored) but no joy there either.

The built in degauss seems to be really wimpy which is why I'm having the issue I think. 

Also I have noticed that there now seems to be a third spot developing  in the bottom middle of the screen.

I haven't taken the screen apart yet to check the yoke, but I was wondering if the built in speakers could be causing an issue, however they are no where near any of the colour distortions.

Perhaps I should mention that it is a 33 inch screen, I forgot that earlier.

[censei]

The degaussing coils that are supplied with 33" monitors aren't sufficient enough to remove strong magnetic discoloration. Try manually degaussing your monitor with a degausser and not a magnet.

[gibbous]

I'm no TV tech, but could the built-in degausser be causing problems?  Perhaps it's not turning off or just staying on the whole time?

[Harry Potter]

I think they can't do that. A degausser would burn out if on all the time.

Is that right?

[Teebor]

Yep, the degaussing coil would destroy itself if left on for too long.

I put an old 17 inch screen with a monster degaussing coil in it face to face with the 33inch screen and it has cleared the majority of the problem on the screen now, I can use it much better.

BUT there is still a heavy spot in the top right corner and the bottom left looks like its going to go given the chance. 

I still havent had time to look inside but I have found a tv repair shop at the end of my road that will degauss the screen for

[Ken Layton]

The built-in degausser wrapped around the picture tube was never intended to be used for anything more than very light use. Moderate, severe, or very strong discoloration requires the use of a handheld manual degausser.

Never use a magnet as you'll magnetize the picture and make the problem worse. Manual degausser coils are powered by alternating current from the wall creating an alternating magnetic field.

[Lilwolf]

btw, the cause is probably the speakers in your backseat.  Seen it happen a few times...

Where do you live?  I have a degausser in ohio (cinci area) you can borrow if your local.  Very handy to keep around.  I got mine on ebay for 20 bucks shipped... usually go for around 30-40 though. 

As for real maginets.  I had my arcade crt fixed (before I got a degausser) with two maginets I places in the back of my cabinet...really... it worked.  But if the maginets moved... then it was really bad...

[fredster]

The cheesy way of degaussing is to get a soldering GUN, not the pencil soldering tools, but one of the ones with the trigger.

Take it and turn it on over the monitor and start going in a circle while the monitor is running.  Make the circle bigger and bigger until all of the marks are gone.

It's like a kentuckian deguassing tool, but I've used it on cocktails and it works.

[Teebor]

I'm in the UK so no borrowing a wand for me

I don't have a soldering Gun sadly, just a normal soldering iron with large base unit.

I saw a really funny video of a guy attaching two magnets to a drill and running it at high speed near the screen to remove any bad spots.  In theory its kind of sound but you have to be crazy to do it.

If anyone's interested I will see if I can find the link.

[gibbous]

I saw a really funny video of a guy attaching two magnets to a drill and running it at high speed near the screen to remove any bad spots.  In theory its kind of sound but you have to be crazy to do it.

If anyone's interested I will see if I can find the link.

Are you talking about the demo they did on an episode of the Screen Sav...um I mean "Attack of the Show" on G4?

http://www.g4tv.com/attackoftheshow/blog/AOTB/post/466253/Screw_This_Degaussing_Drill.html

[Teebor]

Yeah thats the one

I'm sure it works really  but I am also sure that I am not going to try it