UK Vintage Radio Repair and Restoration Powered By Google Custom Search Vintage Radio and TV 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 1st Jan 2022, 5:45 pm   #1
AidanCroft
Tetrode
 
Join Date: Feb 2021
Location: Crewe, Cheshire, UK.
Posts: 66
Default Strange wide vertical stripe

Any guess what's causing the stripe in the attached photo? I'm using a Hedgehog converter.

Kind regards,

Aidan.
Attached Thumbnails
Click image for larger version

Name:	20220101_164239.jpg
Views:	463
Size:	43.1 KB
ID:	248787  
AidanCroft is offline  
Old 1st Jan 2022, 10:11 pm   #2
John123
Heptode
 
Join Date: Jan 2007
Location: Luton, Bedfordshire, UK.
Posts: 891
Default Re: Strange wide vertical stripe

I'm not familiar with this device. Perhaps a humbar of some sort? Maybe try a different PSU or mains adaptor.
__________________
Regards,
John
John123 is offline  
Old 1st Jan 2022, 10:22 pm   #3
Sideband
Dekatron
 
Sideband's Avatar
 
Join Date: Oct 2003
Location: Croydon, Surrey, UK.
Posts: 7,549
Default Re: Strange wide vertical stripe

Can be caused by line pulses getting in to the video signal. If you have restored the TV, check lead dressing. Make sure that any wires from the CRT base socket are not draping across the video stages etc.

Could also be caused by local interference, the power supply to your Hedgehog for instance could be radiating excessively and the interference could be being picked up by the aerial cable (I had a similar problem from my digi-box PSU). Any external PSU's you have near the TV may cause problems.
__________________
There are lots of brilliant keyboard players and then there is Rick Wakeman.....
Sideband is offline  
Old 1st Jan 2022, 11:03 pm   #4
murphyv310
Dekatron
 
murphyv310's Avatar
 
Join Date: Sep 2006
Location: Kilmarnock, Ayrshire, UK.
Posts: 5,420
Default Re: Strange wide vertical stripe

It's off tune.
Try adjusting the fine tuner or the RF oscillator.
Seen it many times before 405 was switched off.
__________________
Cheers,
Trevor.
MM0KJJ. RSGB, GQRP, WACRAL, K&LARC. Member

Last edited by murphyv310; 1st Jan 2022 at 11:32 pm.
murphyv310 is offline  
Old 2nd Jan 2022, 1:07 am   #5
Graham G3ZVT
Dekatron
 
Graham G3ZVT's Avatar
 
Join Date: May 2010
Location: Greater Manchester, UK.
Posts: 18,676
Default Re: Strange wide vertical stripe

A white vertical rope effect can by caused by EHT corona-discharge or "brushing" being picked up by the tuner. It's most noticeable at Band I frequencies.
__________________
--
Graham.
G3ZVT
Graham G3ZVT is offline  
Old 2nd Jan 2022, 10:04 am   #6
murphyv310
Dekatron
 
murphyv310's Avatar
 
Join Date: Sep 2006
Location: Kilmarnock, Ayrshire, UK.
Posts: 5,420
Default Re: Strange wide vertical stripe

Quote:
Originally Posted by rambo1152 View Post
A white vertical rope effect can by caused by EHT corona-discharge or "brushing" being picked up by the tuner. It's most noticeable at Band I frequencies.
Hi.
The rope effect is different to what the OP has, it's far more noticeable than what he has.
When you tune further toward and past the sound carrier the picture looks more sharp for some reason the fly back time then seems to be picked up by the front end. Some sets are more prone to this, TRFs are virtually immune but the more "modern" the likelihood is greater. If the alignment is good and the set not twiddled tuning for best sound then the issue completely dissapears. A set that has seen the phantom twiddler then it'll be worse.
The effect is more noticeable on scenes like in the OPs photos.
A quick adjust of the fine tuner will resolve the issue. If I'm wrong I'll drop off a Pye FV1 as compensation
__________________
Cheers,
Trevor.
MM0KJJ. RSGB, GQRP, WACRAL, K&LARC. Member
murphyv310 is offline  
Old 2nd Jan 2022, 1:46 pm   #7
PYE 405
Pentode
 
Join Date: Dec 2009
Location: Chatteris, Cambridgeshire, UK.
Posts: 176
Default Re: Strange wide vertical stripe

I agree with Trevor.
It looks off tune and some slight alteration to the fine tuner (or local osc) should solve it. It also looks to have a little too much white after black/ black after white, again indicating slight mis-tuning. Unless alignment is out, the best overall picture should coincide with the maximum sound whilst tuning in.

I must say, on some set's, the band is noticeable on a blank background. Don't expect to always eliminate it entirely.
__________________
Andrew

Last edited by PYE 405; 2nd Jan 2022 at 1:54 pm.
PYE 405 is offline  
Old 2nd Jan 2022, 2:10 pm   #8
tomv893
Diode
 
tomv893's Avatar
 
Join Date: Aug 2021
Location: Wilmslow, Cheshire, UK.
Posts: 5
Default Re: Strange wide vertical stripe

It looks like it is struggling to pick up the luma value at the start of either the odd or even
lines
tomv893 is offline  
Old 2nd Jan 2022, 2:26 pm   #9
PYE 405
Pentode
 
Join Date: Dec 2009
Location: Chatteris, Cambridgeshire, UK.
Posts: 176
Default Re: Strange wide vertical stripe

Here is a similar, but reduced effect, on a set of mine. A slight band is seen just before the D of "DVD" on the screen. With a typical scene, it is not noticeable....
Attached Thumbnails
Click image for larger version

Name:	IMG_6139.jpg
Views:	225
Size:	49.6 KB
ID:	248862   Click image for larger version

Name:	IMG_6143.jpg
Views:	211
Size:	85.1 KB
ID:	248863  
__________________
Andrew
PYE 405 is offline  
Old 3rd Jan 2022, 7:55 pm   #10
Freya
Octode
 
Freya's Avatar
 
Join Date: Jan 2009
Location: Falmouth, Cornwall, UK.
Posts: 1,987
Default Re: Strange wide vertical stripe

Some Humax HDR-T2 freeview boxes can produce this effect, it caused me much head scratching before realising the video source was the cause.
__________________
Stephen
_________"It`s only an old telly" ___
Freya is offline  
Old 8th Jan 2022, 10:10 pm   #11
Sundog-
Triode
 
Sundog-'s Avatar
 
Join Date: Nov 2021
Location: Leighton Buzzard, Bedfordshire, UK.
Posts: 32
Default Re: Strange wide vertical stripe

I remember seeing this off-tune effect back in the 405 days but cannot understand how it happens. Does anyone have a theory?
__________________
John
Sundog- is offline  
Old 9th Jan 2022, 1:06 am   #12
FERNSEH
Dekatron
 
FERNSEH's Avatar
 
Join Date: Mar 2005
Location: Gateshead, Tyne and Wear, UK.
Posts: 7,444
Default Re: Strange wide vertical stripe

The effect is caused by over-shoot of the trailing edge of the sync pulse. The result of the sharp transition between negative to positive.
As mentioned earlier in the topic it is most noticeable when the fine tuner is set to the point just before sound on vision.

DFWB.
FERNSEH is offline  
Old 9th Jan 2022, 2:22 pm   #13
murphyv310
Dekatron
 
murphyv310's Avatar
 
Join Date: Sep 2006
Location: Kilmarnock, Ayrshire, UK.
Posts: 5,420
Default Re: Strange wide vertical stripe

Hi.
Indeed David. The overshoot is caused by being off tune or a badly aligned vision stage and shorting out chokes in the video amplifier, in the main though being off tune.
__________________
Cheers,
Trevor.
MM0KJJ. RSGB, GQRP, WACRAL, K&LARC. Member
murphyv310 is offline  
Old 11th Jan 2022, 1:54 pm   #14
Sundog-
Triode
 
Sundog-'s Avatar
 
Join Date: Nov 2021
Location: Leighton Buzzard, Bedfordshire, UK.
Posts: 32
Default Re: Strange wide vertical stripe

Quote:
Originally Posted by FERNSEH View Post
The effect is caused by over-shoot of the trailing edge of the sync pulse.

DFWB.
Thank you, that hadn't crossed my mind. I suppose it also depends on how well the flyback blanking works.
__________________
John
Sundog- is offline  
Closed Thread

Thread Tools



All times are GMT +1. The time now is 6:10 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 - 2024, vBulletin Solutions, Inc.
Copyright ©2002 - 2023, Paul Stenning.