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General Category => Technical Support - General => Topic started by: Shyloc on 19:50, 21 May 18

Title: CTM 644 screen
Post by: Shyloc on 19:50, 21 May 18
Hi, I'm having a problem with my monitor, I'm getting red patches on the left side, and green patches on the right side, when on the default blue intro screen.


I'm nervous of contacting local TV repair shops due to the age of the screen, but I'd like it fixed.


Any ideas? Anyone had the same problem and managed to fix it??
Title: Re: CTM 644 screen
Post by: Bryce on 08:07, 22 May 18
Hi  Shyloc,     congratulations if you can still find a local TV repair shop, in most places they don't exist any more. Can you post a picture of the discolouring. It sounds like the screen just needs to be digaussed, but there are a few other things it could be.
Bryce.
Title: Re: CTM 644 screen
Post by: Shyloc on 08:39, 22 May 18
Hi thanks, I think the degaussing issue is what i've reseached also, how would i go about that?


Theres also a little green patch on the upper right...


A little review of my clothes airer would be apperciated also :)



(https://farm1.staticflickr.com/943/28400249928_a1758fac89_c.jpg)
Title: Re: CTM 644 screen
Post by: Bryce on 08:54, 22 May 18
The clothes airer seems fine, good consistent colouring throughout and peg placement seems to be optomised too. It possibly needs some balancing out, but a little strategic sock sorting should get that good again.
   

Regarding the screen, yes, looks like you need to degauss it. Was it left near something highly magnetic? A big speaker perhaps? You can usually find cheap digaussers on ebay, or even experiment with a permanent magnet and see if you can fix it manually. You need to use the side of the magnet that has both North and South, not the North or South end.

Bryce.
Title: Re: CTM 644 screen
Post by: Shyloc on 09:08, 22 May 18
One of these devices Bryce??


(https://farm1.staticflickr.com/825/41552310234_f1ebb8a522_c.jpg)
Title: Re: CTM 644 screen
Post by: Bryce on 09:31, 22 May 18
That would be a bit difficult to use because it's made for magnetising/de-magnetising tools and the magnetic field is concentrated on the inside. These work quite well:  https://www.ebay.co.uk/itm/New-Screwdriver-Tweezers-220v-Screws-Part-Watch-Demagnetizer-Electrical-Repair/152962132443 (https://www.ebay.co.uk/itm/New-Screwdriver-Tweezers-220v-Screws-Part-Watch-Demagnetizer-Electrical-Repair/152962132443Inside) Inside there's a coil (looks like a onesided transformer, being fed AC, so the field is switching the whole time and degausses the CRT. To use it you just hold it to the offending area and then move it slowly away from the screen.

Bryce.
Title: Re: CTM 644 screen
Post by: Shyloc on 09:49, 22 May 18
that link was dead, I've used it to search though... are we talking about this.....


(https://farm1.staticflickr.com/979/40467446870_9b7e62b605_c.jpg)
Title: Re: CTM 644 screen
Post by: Bryce on 10:20, 22 May 18
Hmm, yup the link doesn't work, but yes, that's the thing I was referring to. They sell for under €10.

Bryce.

Title: Re: CTM 644 screen
Post by: ||C|-|E|| on 14:29, 23 May 18
If you live near Oxford I actually even have a degaussing coil made for CRTs...  :)
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