UK Vintage Radio Repair and Restoration Powered By Google Custom Search Vintage Radio Service Data

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > Specific Vintage Equipment > Vintage Television and Video

Notices

Vintage Television and Video Vintage television and video equipment, programmes, VCRs etc.

Closed Thread
 
Thread Tools
Old 16th Dec 2018, 1:52 am   #61
Refugee
Dekatron
 
Refugee's Avatar
 
Join Date: Apr 2012
Location: Worksop, Nottinghamshire, UK.
Posts: 4,260
Default Re: CRT is brighter to one side [Hitachi CTP213]

There is a lot of capacitor streaking on the video most likely from capacitors in the RGB drivers.
Quite a lot of CRT sets will only need the RGB driver circuits on the tube base circuit board fitted with new capacitors for a complete cure.
The circuit board will need to be very carefully removed from the tube base and can in most cases can be worked on without removing the chassis.
Just make sure no side ways force is applied to the tube neck because it is fragile and the set will be scrap if you break it.
Refugee is online now  
Old 16th Dec 2018, 2:16 am   #62
19Seventy7
Heptode
 
19Seventy7's Avatar
 
Join Date: Jun 2018
Location: London, UK.
Posts: 782
Default Re: CRT is brighter to one side [Hitachi CTP213]

Will definately make sure to be very careful with it all (I generally am with older tech, even with use, and not working on it) Should I replace all capacitors on the RGB? I am happy to do so, and wouldn't give the best picture possible?

I will be using the TV quite a bit so, I don’t really want to cut back.

Are there any reccomended suppliers of capacitors? (I have found a seller online who do a range of specifications, but would much rather ones that have been tried tested, and are reccomended)

Thanks
19Seventy7 is offline  
Old 16th Dec 2018, 2:25 am   #63
Refugee
Dekatron
 
Refugee's Avatar
 
Join Date: Apr 2012
Location: Worksop, Nottinghamshire, UK.
Posts: 4,260
Default Re: CRT is brighter to one side [Hitachi CTP213]

I would go for one of the "branded" suppliers like Farnell/CPC or RS.
Rubycon are my preferred choice but Panasonic also have good reports.
Some cheap suppliers on the web are not as good.
If you look at the colour of the streaking and follow the wires you could find the exact capacitor. When I have done mostly computer screens I do them in sets of three changing the same one in each of the three guns.
These capacitors are very polarity sensitive so do make sure they are the right way round.
Refugee is online now  
Old 16th Dec 2018, 2:50 am   #64
19Seventy7
Heptode
 
19Seventy7's Avatar
 
Join Date: Jun 2018
Location: London, UK.
Posts: 782
Default Re: CRT is brighter to one side [Hitachi CTP213]

I’ll look at them suppliers, and see what capacitors I need and then hopefully make an order.

I also have another issue, which arose this evening.

When I took the pictures earlier, I used my Atari, and my brother decided to have a go on the Atari, connected to my TV. The TV must’ve been on for roughly an hour or more, and after a while, there was a very strong burning smell.

As the smell increased, the picture grew dim and there was a very odd electronic noise coming from inside.

I’ve never turned something off so quick. It of course remains unplugged now (and when not in use).

I havent taken the back off yet to see if any damage has been done, but could it just be something got too hot (possibly a or the faulty capacitor?) and burnt the thick layer of dust inside?

It doesnt have a burning smell at all now, not even when smelling down the ventilation at the back.

I really hope it’s nothing major.

Thanks

Last edited by 19Seventy7; 16th Dec 2018 at 2:55 am.
19Seventy7 is offline  
Old 16th Dec 2018, 3:14 am   #65
Refugee
Dekatron
 
Refugee's Avatar
 
Join Date: Apr 2012
Location: Worksop, Nottinghamshire, UK.
Posts: 4,260
Default Re: CRT is brighter to one side [Hitachi CTP213]

It could be a number of things.
Something will have got hot enough for you to see it and take a photo.
Refugee is online now  
Old 16th Dec 2018, 3:32 am   #66
19Seventy7
Heptode
 
19Seventy7's Avatar
 
Join Date: Jun 2018
Location: London, UK.
Posts: 782
Default Re: CRT is brighter to one side [Hitachi CTP213]

I’ll take the back off tomorrow, and if I see anything I’ll take a picture and post it on here.

I didn't see anything inside glowing or sparking or anything. (I did look to see if something was)
The only other indication was the noise and the CRT going dim.

Thanks
19Seventy7 is offline  
Old 16th Dec 2018, 5:09 am   #67
Boater Sam
Banned
 
Join Date: Dec 2013
Location: Middlewich, Cheshire, UK. & Winter in the Philippines.
Posts: 3,897
Default Re: CRT is brighter to one side [Hitachi CTP213]

Another one bites the dust?

Please accept that old electronic equipment needs some attention before it is used for a long time, it's not like a new one.
Hopefully the damage done will not be terminal though if you have no equipment and no experience I fear it will be.
Boater Sam is offline  
Old 16th Dec 2018, 11:51 am   #68
1100 man
Octode
 
1100 man's Avatar
 
Join Date: Apr 2016
Location: Ventnor, Isle of Wight, & Great Dunmow, Essex, UK.
Posts: 1,061
Default Re: CRT is brighter to one side [Hitachi CTP213]

That's very sad Welcome to the world of trying to keep old TV's working!!

My guess, and it is only a guess at this stage based on your description, is that the insulation has failed on the tripler or line output transformer. The tripler, or more correctly EHT multiplier, is a highly stressed component- there's 25Kv in there trying to get out!

These items were very regular failure items on all TV's back in the '70's & '80's. Yours is probably the original one so has done very well in it's 40 odd year life.

The tripler is that grubby white thing standing up on top of the chassis in the right of your picture in post 44. It's also got the focus knob built into it as well.
The line output transformer (LOPT), is immediately below it and will have a thick wire coming out of it going to the tripler.

Carefully examine these items for any burnt areas or melted bits- it will be fairly obvious if this is the cause.

Also examine the print side of the circuit board these components are mounted to- often a print burn up can cause the problem you describe.

Make sure the set is unplugged before looking and you need to be VERY aware that the EHT connection (that round plastic disc with a wire coming out at the top of the tube) can hold a charge up to 25Kv (yes that's 25 thousand volts!) almost indefinitely under certain circumstances. Don't disconnect it or touch it. Just look visually at this stage.

I hope it's not the tripler or the LOPT that has failed as both of these are now very difficult problems to solve.

Fingers crossed
Nick
1100 man is offline  
Old 16th Dec 2018, 12:04 pm   #69
ben
Dekatron
 
ben's Avatar
 
Join Date: Aug 2006
Location: Madrid, Spain / Wirral, UK
Posts: 5,539
Default Re: CRT is brighter to one side [Hitachi CTP213]

I think it really is time to seek a local technician. We're now into risky territory, especially for the uninitiated.
__________________
Regards,
Ben.
ben is offline  
Old 16th Dec 2018, 12:11 pm   #70
ms660
Dekatron
 
ms660's Avatar
 
Join Date: Apr 2011
Location: Cornwall, UK.
Posts: 8,422
Default Re: CRT is brighter to one side [Hitachi CTP213]

I might be wrong but that doesn't look like an EHT tripler to me, it looks like the focus assembly, according to a schematic I'm looking at the EHT rect. is part of the LOPTX.

The RGB output HT decoupler(s) appear to be on the main power/deflection board
(2 x 3.3uF) and not on the CRT panel so far as I can make out.

Lawrence.
ms660 is offline  
Old 16th Dec 2018, 12:21 pm   #71
19Seventy7
Heptode
 
19Seventy7's Avatar
 
Join Date: Jun 2018
Location: London, UK.
Posts: 782
Default Re: CRT is brighter to one side [Hitachi CTP213]

I’ll definitely get someone in, maybe there is someone on this forum, that could help? I'm just above London.

After I post this, I'll take the back off and post a picture, or more.

I haven't touched, and won't touch, anything inside as I didn't want to do any more harm than good.

Thank you all for your replies too, I think iId be at a total loss without your help!

Thanks
19Seventy7 is offline  
Old 16th Dec 2018, 12:38 pm   #72
19Seventy7
Heptode
 
19Seventy7's Avatar
 
Join Date: Jun 2018
Location: London, UK.
Posts: 782
Default Re: CRT is brighter to one side [Hitachi CTP213]

Could you possibly post a picture/scan of the schematic if possible please? We’ve been trying to find one, and I’ve searched all over the internet with no luck.

Thanks
19Seventy7 is offline  
Old 16th Dec 2018, 12:51 pm   #73
ms660
Dekatron
 
ms660's Avatar
 
Join Date: Apr 2011
Location: Cornwall, UK.
Posts: 8,422
Default Re: CRT is brighter to one side [Hitachi CTP213]

This is the nearest I've found so far:

https://elektrotanya.com/hitachi_crp.../download.html

Lawrence.
ms660 is offline  
Old 16th Dec 2018, 12:53 pm   #74
1100 man
Octode
 
1100 man's Avatar
 
Join Date: Apr 2016
Location: Ventnor, Isle of Wight, & Great Dunmow, Essex, UK.
Posts: 1,061
Default Re: CRT is brighter to one side [Hitachi CTP213]

Quote:
Originally Posted by ms660 View Post
I might be wrong but that doesn't look like an EHT tripler to me, it looks like the focus assembly, according to a schematic I'm looking at the EHT rect. is part of the LOPTX.
I think you are quite correct, Lawrence! I need to get my eyes tested!! Magnifying the photo in post 44, the EHT lead clearly comes from the LOPT straight to the tube. The white lump would appear to be just the focus assembly although it's quite large.

To have the EHT rect as part of the LOPT would have been very unusual at that time. Does your circuit show it as a diode split transformer or a conventional multiplier design?

"I think it really is time to seek a local technician. We're now into risky territory, especially for the uninitiated."

Yes, I would have to agree with that:- we'll just nip back to 1980 and take it to the local repair shop!!

Cheers
Nick
1100 man is offline  
Old 16th Dec 2018, 12:56 pm   #75
19Seventy7
Heptode
 
19Seventy7's Avatar
 
Join Date: Jun 2018
Location: London, UK.
Posts: 782
Default Re: CRT is brighter to one side [Hitachi CTP213]

Click image for larger version

Name:	image.jpg
Views:	68
Size:	49.7 KB
ID:	174703I’ve taken the back off the TV, and looked, double checked and triple checked, and even got a second opinion, and nothing looks burnt or melted which is a relief.

I'll post some pictures of it now, maybe you all can see something that I can't, as you have a lot more idea of what you’re looking at.

Edit: thank you for the schematic!

Thanks
19Seventy7 is offline  
Old 16th Dec 2018, 1:02 pm   #76
19Seventy7
Heptode
 
19Seventy7's Avatar
 
Join Date: Jun 2018
Location: London, UK.
Posts: 782
Default Re: CRT is brighter to one side [Hitachi CTP213]

The photos didnt attach properly

Here they are:
Attached Thumbnails
Click image for larger version

Name:	18DED10A-D62C-4EA2-B7D7-E3FBC1AE9257.jpg
Views:	99
Size:	66.5 KB
ID:	174704   Click image for larger version

Name:	7B09E86B-D8A8-421B-9141-AA7AEC5F6882.jpg
Views:	95
Size:	78.2 KB
ID:	174705   Click image for larger version

Name:	64672A0E-FE5C-48B4-A151-85327FEB756E.jpg
Views:	93
Size:	46.7 KB
ID:	174706   Click image for larger version

Name:	FBFF754E-5B5B-44F5-94C8-73F5C18F1090.jpg
Views:	93
Size:	80.4 KB
ID:	174707  
19Seventy7 is offline  
Old 16th Dec 2018, 1:09 pm   #77
mark2collection
Hexode
 
mark2collection's Avatar
 
Join Date: Jul 2010
Location: Royal Berkshire, UK.
Posts: 325
Default Re: CRT is brighter to one side [Hitachi CTP213]

This may sound daft but it did cure the faded-to-one-side effect.

Back in the late 90's a Mitsubishi set came in, identical fault as your Hitachi ... very long story cut short, the set had a factory 'mod' using a link-wire and hot glue to secure the middle section of the 'mod' wire.

The glue was on the track-side of the PCB, across the video/RGB IC ... The glue was conductive.

Removing the glue, the TV was cured. Worth a look(?)

Let's hope the aroma from your set is 'the oldness wearing off'

Mark
mark2collection is offline  
Old 16th Dec 2018, 1:25 pm   #78
19Seventy7
Heptode
 
19Seventy7's Avatar
 
Join Date: Jun 2018
Location: London, UK.
Posts: 782
Default Re: CRT is brighter to one side [Hitachi CTP213]

I’ll have a look now. Where is the PCB as i’m not all too familiar with names and functions.

I still don’t know where the smell came from. I think it was just dust burning.
Thanks
19Seventy7 is offline  
Old 16th Dec 2018, 1:36 pm   #79
ms660
Dekatron
 
ms660's Avatar
 
Join Date: Apr 2011
Location: Cornwall, UK.
Posts: 8,422
Default Re: CRT is brighter to one side [Hitachi CTP213]

Be aware that the chassis is live with respect to earth when the set is switched on.....

I wouldn't fiddle around inside the set with power applied unless the set was powered via a safety isolating transformer.

Lawrence.
ms660 is offline  
Old 16th Dec 2018, 1:40 pm   #80
19Seventy7
Heptode
 
19Seventy7's Avatar
 
Join Date: Jun 2018
Location: London, UK.
Posts: 782
Default Re: CRT is brighter to one side [Hitachi CTP213]

I’m very cautious when the back is off, even when unplugged, just in case it’s still holding a charge.

So if it’s plugged in, I’ll take the best care possible.

Thanks
19Seventy7 is offline  
Closed Thread

Thread Tools



All times are GMT +1. The time now is 10:33 am.


All information and advice on this forum is subject to the WARNING AND DISCLAIMER located at https://www.vintage-radio.net/rules.html.
Failure to heed this warning may result in death or serious injury to yourself and/or others.


Powered by vBulletin®
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Copyright ©2002 - 2019, Paul Stenning.