English Amiga Board


Go Back   English Amiga Board > Support > support.Hardware

 
 
Thread Tools
Old 27 January 2019, 17:24   #1
WallyGR
Registered User

 
Join Date: Sep 2018
Location: Athens Greece
Posts: 17
Amiga CD32 SVideo TV interference

Hi all,

I have this wacky issue with my (French?) AmigaCD32.

When I am using the SVideo (with simple cable that plugs into a Svideo2Scart adapter or with that http://retrocables.es/tienda/index.p...duct&id_lang=4 ) I get strong TV interference in the background. I can litterally see TV program scrolling as shadow in the background.

The most funny thing is that when I "wingle" the cable, I get get into a very clear monochrome display with no shadows at all but...without colour.

When in Composite, I get what I would expect from a Composite display...and no TV interference.

Any clues?

Thanx
WallyGR is offline  
Old 28 January 2019, 13:40   #2
AmigaHope
Registered User
 
Join Date: Sep 2006
Location: New Sandusky
Posts: 137
Quote:
Originally Posted by WallyGR View Post
Hi all,

I have this wacky issue with my (French?) AmigaCD32.

When I am using the SVideo (with simple cable that plugs into a Svideo2Scart adapter or with that http://retrocables.es/tienda/index.p...duct&id_lang=4 ) I get strong TV interference in the background. I can litterally see TV program scrolling as shadow in the background.

The most funny thing is that when I "wingle" the cable, I get get into a very clear monochrome display with no shadows at all but...without colour.

When in Composite, I get what I would expect from a Composite display...and no TV interference.

Any clues?

Thanx
At first I thought it was strange because the Greek analog switchoff was in 2015, then I read that some stations are still broadcasting in analog because the government never actually enforces the law to make them shut off their analog signals. Typical Greece. xD

It could be a problem with your TV, but it could also be that the problem is the cables are not carrying terminating properly -- this could be in your SCART cable, or your converter, or your s-video cable. Basically what is happening is that the cable is acting as a crude tuner, converting the 1-meter range signals (channel 7 possibly?) to baseband. The luma portion of analog television is an AM signal so no demodulator is needed to tune it (just like how you can hear AM radio station interference sometimes in random electronics that happen to have the right length of wire in them, or even in tooth fillings!)

Best guess is that you need to replace your cables and check the soldering of your jacks (the wiggling is concerning). Check them with other S-video sources.

Also if your CD32 has S-Video then it is not French. French CD32s have 8-pin RGB jacks in the back instead of 4-pin S-Video. Also a French CD32 would output a SECAM chroma signal instead of PAL, and some TVs sold in the EU do not support SECAM since every EU SECAM country except France switched from SECAM to PAL (Greece switched in 1992). If you *ARE* using a SECAM-preference TV (either an older Greek TV or a French TV or whatever) it could be that it supports PAL and SECAM on composite but the SCART chroma line expects only SECAM, etc.
AmigaHope is offline  
Old 28 January 2019, 19:45   #3
WallyGR
Registered User

 
Join Date: Sep 2018
Location: Athens Greece
Posts: 17
Impressive knowledge man!

Well I do have the French version and I broke the plastic cap from the SVideo plug to let it in.
Attached Thumbnails
Click image for larger version

Name:	IMG_20190128_193917.jpg
Views:	49
Size:	91.3 KB
ID:	61803   Click image for larger version

Name:	IMG_20190128_194028.jpg
Views:	50
Size:	78.5 KB
ID:	61804  
WallyGR is offline  
Old 29 January 2019, 09:53   #4
Jope
-
Jope's Avatar
 
Join Date: Jul 2003
Location: Helsinki / Finland
Age: 38
Posts: 7,016
.. but as said, it's not an S-Video socket in that market area.
Jope is offline  
Old 01 February 2019, 09:58   #5
AmigaHope
Registered User
 
Join Date: Sep 2006
Location: New Sandusky
Posts: 137
Quote:
Originally Posted by WallyGR View Post
Impressive knowledge man!

Well I do have the French version and I broke the plastic cap from the SVideo plug to let it in.
...ummm there's your problem then. You're plugging an s-video cable into a completely different kind of socket, potentially damaging it in the process, and it's a miracle you even got any kind of image at all out of it. The reason it even slightly worked is that the luma pin on the French CD32 8-pin video connector lines up with the S-Video luma pin on the 4-pin S-Video connector. The chroma pin is also actually in the same place I think.

The problem is that the other two pins in the S-Video plug are ground returns for the luma and chroma signals, but on the French CD32 DIN plug they line up with (I *think*) the left and right audio signals, not ground! This explains why your signal is screwed up -- it's not grounded and is getting random (potentially damaging) voltage fluctuations where it expects ground to be. Luma info is simple amplitude modulation so you will see *something*, but chroma is quadrature modulated so the noise messes it up more. This also explains why you're picking up analog TV, you're taking an ungrounded line and this effectively turns the cable into an antenna (that tunes at harmonic wavelengths of the length of the cable). You probably live close to a fairly powerful TV transmitter.

You're going to need a different cable. The good news is that the CD32's mini-din outputs RGB and audio as well as Y/C so you can get full RGB+stereo on your SCART connection if you want. The bad news is that you're going to have to get a rare/custom cable. There are people who make this cable though. Hopefully you have not damaged anything by using the wrong cable and wiggling it around so much.

In the meantime, stop what you're doing right now. This is like jamming your USB charging cable into the wall power socket and wondering why your phone is on fire instead of fully charged.

Last edited by AmigaHope; 01 February 2019 at 10:29.
AmigaHope is offline  
Old 01 February 2019, 16:43   #6
WallyGR
Registered User

 
Join Date: Sep 2018
Location: Athens Greece
Posts: 17
Oh!

Thanx!
WallyGR is offline  
Old 01 February 2019, 20:10   #7
RoC
Registered User

 
Join Date: May 2011
Location: Italy
Posts: 104
Ami.goun makes high quality secam cables on Amibay for the CD32.

Take a look if that helps
RoC is offline  
Old 05 February 2019, 14:59   #8
WallyGR
Registered User

 
Join Date: Sep 2018
Location: Athens Greece
Posts: 17
I will do. Thanx for the info!
WallyGR is offline  
 


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Similar Threads
Thread Thread Starter Forum Replies Last Post
rgb interference after installing idefix Glen M support.Hardware 10 24 May 2017 22:54
Sprite Interference in Kick Off 2 msayed1977 support.WinUAE 4 20 February 2014 10:36
Screen Interference When Using Blizzard 1230-IV gleng support.Hardware 4 13 January 2010 12:20
Amiga SVideo Adapters A500 / A600 / A1000 / A1200 / A4000 Zetr0 MarketPlace 194 12 December 2009 21:48
CD32 SVideo Out mini-DIN with 8 pins Calgor support.Hardware 18 30 January 2009 16:40

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 +2. The time now is 21:42.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2019, vBulletin Solutions Inc.
Page generated in 0.07331 seconds with 14 queries