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 > Television Standards Converters, Modulators etc

Notices

Television Standards Converters, Modulators etc Standards converters, modulators anything else for providing signals to vintage televisions.

Closed Thread
 
Thread Tools
Old 11th Mar 2019, 4:19 pm   #1
PsychMan
Octode
 
PsychMan's Avatar
 
Join Date: Jun 2013
Location: Fleet, Hampshire, UK
Posts: 1,240
Default B&W Output From Modulator

When using a Mercury RF modulator connected to an early 70s Sony Colour set, some sources display in black and white. You can often see SOME faint colour present, but very little. For all intents it is black and white.

DVD player, VCR, all fine through the same modulator. But for example, modern Atari joystick with built in games and composite output - B&W.

Just curious the technical reason why this is and whether it can be rectified somehow?
PsychMan is offline  
Old 11th Mar 2019, 6:08 pm   #2
kan_turk
Hexode
 
kan_turk's Avatar
 
Join Date: Mar 2014
Location: Dublin, Ireland
Posts: 255
Default Re: B&W Output From Modulator

Sounds like non-standard output from some devices (NTSC perhaps?) as modulator is performing correctly when fed with valid source
It might help to list the ‘non performing’ sources in order to diagnose further
kan_turk is offline  
Old 11th Mar 2019, 6:23 pm   #3
PsychMan
Octode
 
PsychMan's Avatar
 
Join Date: Jun 2013
Location: Fleet, Hampshire, UK
Posts: 1,240
Default Re: B&W Output From Modulator

Thanks. I did wonder if it was NTSC, but one such device was used on the composite input of a 90s CRT and that showed the colour fine. Which if it was NTSC I believe it would not?

All of the devices so far have been gaming related. Atari 2600 joystick with built in games, like this https://www.amazon.co.uk/Atari-Retro.../dp/B076BS5WVN

and lots of similar and cheaper devices. "Retro FC Handheld" for example, which is a "NES on a chip" device with a load of games on flash memory. All cheapy tat, which might explain why it doesn't work so well. Just curious as to the technical reason and if they could be made to work better
PsychMan is offline  
Old 11th Mar 2019, 8:16 pm   #4
Lloyd 1985
Octode
 
Lloyd 1985's Avatar
 
Join Date: Jun 2008
Location: Coningsby, Lincolnshire, UK.
Posts: 1,562
Default Re: B&W Output From Modulator

What Sony TV is it? I’ve got 2 KV-1330’s which have trouble with some sources, I use a Toshiba VCR DVD combo as a signal source, when playing a DVD it works fine, and VHS tapes too, but some freeview boxes and my Sumvision SD card video player show incorrect colours on the Sony’s. I put it down to the simple PAL decoder used in them not decoding substandard colour signals correctly.

Regards
Lloyd
Lloyd 1985 is online now  
Old 11th Mar 2019, 8:42 pm   #5
kan_turk
Hexode
 
kan_turk's Avatar
 
Join Date: Mar 2014
Location: Dublin, Ireland
Posts: 255
Default Re: B&W Output From Modulator

Many recent TVs, both later CRT & LCD etc had multi-system, auto switching decoders which decoded and displayed correctly virtually anything thrown at them - causing not a little head scratching for the poor unfortunate trying to diagnose a fault
kan_turk is offline  
Old 12th Mar 2019, 11:46 am   #6
PsychMan
Octode
 
PsychMan's Avatar
 
Join Date: Jun 2013
Location: Fleet, Hampshire, UK
Posts: 1,240
Default Re: B&W Output From Modulator

Its a Sony KV-1320.

I guess the colour coding is present on the composite signal and that colour system is passed through the modulator to the TV. So I guess it cant be fixed, interesting to know however.

Knowing very little about televisions Id have expected a composite signal was a composite signal, clearly theres more to it and TV manufacturers have instead decided to accommodate all sorts of variations over time. Interesting
PsychMan is offline  
Old 12th Mar 2019, 2:41 pm   #7
winston_1
Hexode
 
Join Date: Oct 2012
Location: London, UK.
Posts: 300
Default Re: B&W Output From Modulator

It is quite likely the source, the Atari joystick. Either the colour sub carrier is slightly off frequency or the chroma is low. Sony sets are particularly fussy about this.

When I worked in the cable TV industry no colour faults from customers when it appeared OK leaving the headend always seemed to be those with Sony TVs. The fault at the headend was something like a poor connector causing the chroma to be very low.
winston_1 is offline  
Old 12th Mar 2019, 8:36 pm   #8
Karen O
Heptode
 
Karen O's Avatar
 
Join Date: Jul 2011
Location: Bridgnorth, Shropshire, UK.
Posts: 526
Default Re: B&W Output From Modulator

Modern TVs seem very fussy about conformity to standard. I suspect that, in the analogue days, tolerance of design was essential due to component production spread. In this digital age some jobsworth digital circuit can just say 'sorry, that is 0.01% out of spec. I'm not accepting it'.

My daughter couldn't use her old game console on her new TV. I concluded that the TV didn't like the game console's non-interlaced output.

There has been a passion in recent years for taking the schematics of classic consoles and using libraries to put them verbatim onto FPGAs or such like. The result is non-standard outputs from 'modern' hardware.

Oh, for good old fashioned, tolerant, easy-to-use, gracefully degrading analogue TVs!
__________________
Karen O

Temporal Paradox: Kills all known grandfathers. Dead.
Karen O is offline  
Closed Thread

Thread Tools



All times are GMT +1. The time now is 11:29 pm.


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.