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Old 14th Dec 2018, 4:03 pm   #41
19Seventy7
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Default Re: CRT is brighter to one side

I have taken the back off the set, and I was getting ready to take a photo. but there is a thick layer of dust and my phone (what I use to take photos) needs to charge before I take photos.

I was going to clear the dust off while I waited for the phone to charge, then I remembered I saw another thread where someone's set was dusty, and they was told not to clean it or just yet.

(The OP of that thread had already cleaned it before being told not to, so I don't know why it shouldn't be cleaned, or when)

Will it be okay to clean or should I leave it until someone says otherwise?

Thanks
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Old 14th Dec 2018, 4:13 pm   #42
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Default Re: CRT is brighter to one side

What is the TV model number?
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Old 14th Dec 2018, 4:26 pm   #43
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Default Re: CRT is brighter to one side

I think it's 510HWB22, that's whats on the CRT, along with the series number

I could be wrong as there is another number/code, which is on the cabinet, but is faded and hard to read.

Thanks
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Old 14th Dec 2018, 4:39 pm   #44
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Default Re: CRT is brighter to one side

I have taken some photos of the inside if they may be of any help.
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Old 14th Dec 2018, 4:42 pm   #45
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Default Re: CRT is brighter to one side

The 510HWB22 number is the CRT type, the number on the cabinet back is probably the model.
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Old 14th Dec 2018, 4:51 pm   #46
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Default Re: CRT is brighter to one side

I think it's

0N8F298[Faded number or letter or just a gap]213

That makes a little more sense as the model is CTP 213

Thanks
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Old 14th Dec 2018, 11:35 pm   #47
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Default Re: CRT is brighter to one side [Hitachi CTP213]

At last! You've finally got a TV! Looks a sensible purchase to me. PIL tube too rather than a delta gun type which means much less setting up to do.

Whilst it's very tempting to start hoovering out all the dust, it's not always a great idea- at least initially. It can disturb things that don't want disturbing and introduce faults and make your life more complicated!

Those PCB's have a classic 'Hitachi' look about them- especially the IC in the first picture. I'll bet it's never had any components replaced and I would estimate it's from the mid to late '70's.

Hopefully someone can post the relevant part of the circuit now we know the model number. I don't know if it's in later R&TV servicing books?

It should be possible to get it working well and displaying a good picture. All you need now is a vintage VCR to go with it!

All the best
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Old 14th Dec 2018, 11:36 pm   #48
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Default Re: CRT is brighter to one side [Hitachi CTP213]

It is easy to knock PCB presets or other components when dusting so that's probably why it's not the best idea at this stage.

Be especially careful not to knock the little circuit board attached to the end of the tube. If you crack the glass it's game over!

We'd need a schematic diagram to locate the defective capacitor that feeds the RGB output stage. It may be on that small PCB or near the big transformer on the main board.
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Old 15th Dec 2018, 1:04 am   #49
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Default Re: CRT is brighter to one side [Hitachi CTP213]

Quote:
Originally Posted by 1100 man View Post
At last! You've finally got a TV! Looks a sensible purchase to me. PIL tube too rather than a delta gun type which means much less setting up to do.

It should be possible to get it working well and displaying a good picture. All you need now is a vintage VCR to go with it!
I’m very glad i’ve got one, after months of convincing and weeks of looking i’ve finally got one!

I do need to figure out which convergence control sorts out the wonky image, however.

Its funny you say about getting a VCR, as I have actually been looking. (I would love a top loading VCR

Quote:
Originally Posted by ben View Post
It is easy to knock PCB presets or other components when dusting so that's probably why it's not the best idea at this stage.

Be especially careful not to knock the little circuit board attached to the end of the tube. If you crack the glass it's game over!

We'd need a schematic diagram to locate the defective capacitor that feeds the RGB output stage. It may be on that small PCB or near the big transformer on the main board.
Ah, that makes a lot of sense, i didnt dust anything apart from the back panel (to improve ventilation) to be safe. I did wonder if it was to do with knocking or displacing anything inside.

Ill have a search online to see if i can find any schematics.

Ill let you know if i find anything.
Thanks
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Old 15th Dec 2018, 1:29 am   #50
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Default Re: CRT is brighter to one side [Hitachi CTP213]

It would be very useful to be able to display a test card. Then we can see what issues there are with the picture.

How do you propose to get signals into the TV? Almost no DVD players have an RF output that you can feed into the aerial socket. I don't think modern freeview boxes do either.

You can use any old VCR as a modulator even if it doesn't work mechanically. You feed the video & audio output from the DVD or freeview into the VCR and it converts it into an RF signal that can be tuned in on the TV.

There is a link at the top of this page of the forum for a testcard DVD you can use if you can write DVD's.

In the short term, it would be useful to post some screen shots of even just the snowy picture with no signal. If you can get a picture by some means, even better. Take them with the colour control turned down to minimum. The set needs to be able to produce a good black & white picture before it will give a good colour one!

Don't forget the chassis metalwork will probably be at 'half mains potential', so for your purposes, consider it to be 'live'!! Take great care when working on the set while it's on!! We won't know for sure until a circuit diagram is found!

All the best
Nick
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Old 15th Dec 2018, 2:36 am   #51
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Default Re: CRT is brighter to one side [Hitachi CTP213]

You should be able to get a test card from a Freeview box, which you'll probably need to use this analogue TV: https://www.vintage-radio.net/forum/...ad.php?t=46805
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Old 15th Dec 2018, 2:52 am   #52
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Default Re: CRT is brighter to one side [Hitachi CTP213]

I'm not sure the "wonky image" should or could be corrected by attempting to adjust the convergence without looking for a fault first, as it sounds like a geometry fault rather than a convergence setup error, though I have no background in television repair and will defer to the experts.
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Old 15th Dec 2018, 3:30 am   #53
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Default Re: CRT is brighter to one side [Hitachi CTP213]

If the picture is actually slanting to one side, then perhaps the scan coils need a little rotating. Given the high voltage and potential live chassis hazard, it might just be easier to find a retired TV repairman or enthusiast in your local area who can tune it up for you (and carry out any necessary repairs).
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Old 15th Dec 2018, 3:32 am   #54
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Default The Secret Story of the BBC Christmas Tapes

Quote:
Originally Posted by 1100 man View Post
It would be very useful to be able to display a test card. Then we can see what issues there are with the picture.

How do you propose to get signals into the TV?

You can use any old VCR as a modulator even if it doesn't work mechanically. You feed the video & audio output from the DVD or freeview into the VCR and it converts it into an RF signal that can be tuned in on the TV.

In the short term, it would be useful to post some screen shots of even just the snowy picture with no signal. If you can get a picture by some means, even better.
I have an Atari 2600 which connects in straight away with a coaxial connector, so thats how i realised it was a wonky image.
I was planning on getting a VCR (as i do want to play some of my old tapes again) or a modulator, which ever is easiest for me right now. I don’t actually own any DVDs, nor a DVD player.
I should be picking up a freeview box, for analogue TVs (or so the seller says) on Sunday so i can see where that takes me.

I can get pictures to you tomorrow as im not actually at home right now.
Quote:
Originally Posted by John123 View Post
If the picture is actually slanting to one side, then perhaps the scan coils need a little rotating. Given the high voltage and potential live chassis hazard, it might just be easier to find a retired TV repairman or enthusiast in your local area who can tune it up for you (and carry out any necessary repairs).
Oh, i didnt think it would be that bad to sort out (i thought it may have been a somple convergence issue, to be honest, but thats my little knowledge guess..)

I’m happy to get someone to help me too, that wont be an issue. It’s only a slight angle, but still noticable. I’ll ask around and see if there is anyone nearby who can help me, too.
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Old 15th Dec 2018, 5:03 am   #55
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Default Re: CRT is brighter to one side [Hitachi CTP213]

Folk just want to warn you that fixing TVs can be a shocking experience!
Do as little as possible with any power connected, apply lots of common sense and always with one hand in your pocket and you will survive.
The scan coils are around the neck of the tube up against the flare. They can with care be rotated slightly to straighten the picture. They may be secured with a clamp of some sort. Do not force anything, wear safety glasses when working near TV tubes.
Try a tiny rotation with the set disconnected from the mains, then see if it is better.
Beware, high voltages can and do persist long after the set is off. A good rubber glove is a good idea. One hand only remember.
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Old 15th Dec 2018, 8:26 pm   #56
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Default Re: CRT is brighter to one side [Hitachi CTP213]

Before trying to make adjustments to the deflection, first check whether the image is still crooked if you turn the set 90 degrees (e.g. from north facing to east or west facing) or if you place it somewhere else.
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Old 15th Dec 2018, 10:48 pm   #57
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Default Re: CRT is brighter to one side [Hitachi CTP213]

The slant on the raster top shown in then second photo in post#1 looks like scan coil skew adjustment to me.
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Old 15th Dec 2018, 11:46 pm   #58
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Default Re: CRT is brighter to one side [Hitachi CTP213]

Here are the photos.

(I posted a colour as well as black and white, as i thought it could possibly help?)

First image shows the slant, but not too well.. my phone shows it as a 2/3 degree slant, but i dont know how accurate it is.
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Old 16th Dec 2018, 12:09 am   #59
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Default Re: CRT is brighter to one side [Hitachi CTP213]

Do nothing until you change that RGB cap.
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Old 16th Dec 2018, 12:14 am   #60
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Default Re: CRT is brighter to one side [Hitachi CTP213]

Okay. Isn’t the RGB at the neck of the CRT?

Will I need a multimeter to test as I don’t have one. I should be able to get one easily if I need to.

Thanks
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