Videokarma.org

Go Back   Videokarma.org TV - Video - Vintage Television & Radio Forums > Solid State CRT Televisions

We appreciate your help

in keeping this site going.
Reply
 
Thread Tools Display Modes
  #1  
Old 08-05-2013, 09:08 PM
jmetal88 jmetal88 is offline
VideoKarma Member
 
Join Date: Jan 2008
Location: Derby, KS
Posts: 252
Cable Auto-Detection (Toshiba 32AF33)

I have a Toshiba 32AF33 TV that I use in my living room, and it seems to have the ability to detect when an S-Video cable is plugged in to the Video 1 input, and it disables the Composite video input whenever this is the case. The S-Video cable does not have to be connected to a video source for the detection to work, as the Composite input gets disabled even when the other end of the S-Video cable is disconnected.

So I'm curious, how does the TV know when the S-Video cable is plugged in? I get how things like headphone jacks can work, since they can have that contact pair that breaks when the plug is inserted, but I'm just curious how a TV like mine would manage to pull that off with an S-Video jack.

The main reason I'm interested is because I'd kind of like to use a video switch box on this input, and I have a few that handle both Composite and S-Video, but in order to use a Composite device, I always have to reach around behind the TV and unplug the S-Video cable or else I get no picture. I think it would be neat if I could somehow switch out the S-Video input without actually unplugging the cable, perhaps by wiring up a switch that can disable the cable detection when I need it disabled, or something like that.
Reply With Quote
  #2  
Old 08-06-2013, 06:26 AM
zeno's Avatar
zeno zeno is offline
VideoKarma Member
 
Join Date: Mar 2013
Location: New Hampshire
Posts: 4,672
There is a switch built in to the jack. I think its
SPST so quick to defete BUT then the TV wont be looking
for S. It will always be looking for composite.............
Most likely switch goes right to a source switching IC.

73 Zeno
Reply With Quote
  #3  
Old 08-06-2013, 12:18 PM
holmesuser01's Avatar
holmesuser01 holmesuser01 is offline
VideoKarma Member
 
Join Date: Jul 2005
Location: Asheville NC
Posts: 1,731
What Zeno said.

I had a set once in my shop that insisted that something was plugged into the S video jack, when there was nothing. The switch in the jack was bad.

Had to order a new one from the manufacturer. It was crazy expensive at the time.

This was right after S-video came along on TV's.
Reply With Quote
  #4  
Old 08-06-2013, 06:52 PM
jmetal88 jmetal88 is offline
VideoKarma Member
 
Join Date: Jan 2008
Location: Derby, KS
Posts: 252
Okay, I'll have to look at the PCB sometime and see if I can't intercept the traces coming from the switch.
Reply With Quote
Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 10:04 AM.



Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
©Copyright 2012 VideoKarma.org, All rights reserved.