Cox Electronics SECAM encoder - UK Vintage Radio Repair and Restoration Discussion Forum

cmjones01 · 30th Aug 2010, 3:32 pm

Here's something that doesn't crop up every day. A Cox Electronics SECAM encoder. Ideal for the collector of French TV sets who wants to remain in the analogue domain. Plenty of adjustments to twiddle.

I have no idea if it works or not: it was given to me free when I bought a frequency counter a few months ago. I'll never use it so someone else can have it.

Free of charge in Cambridge, UK.

Chris

Kat Manton · 30th Aug 2010, 3:41 pm

Hi,

I'd be interested in this, if it's possible to arrange posting it to me (and doesn't end up hideously expensive!)

I'm interested in (analogue) television systems in general; a long-term aim is being able to encode and decode all of them. SECAM is on the list... (One of my monitors and possibly one TV will theoretically do SECAM though I've been unable to try them.)

Cheers, Kat

AC/HL · 31st Aug 2010, 11:38 pm

If it can be got to Peterborough (Werrington) I can bring it to Leeds?

ppppenguin · 1st Sep 2010, 8:34 am

If I remember correctly from days at Cox the 253 SECAM coder takes RGB inputs at 0.7Vp-p plus mixed sync. I don't think it needs any other pulses. If you're lucky it will have the colour bar sub-board installed - this wasn't always fitted. I don't have the circuits or any other data except possibly for the colour bar sub-board and the PSU.

cmjones01 · 1st Sep 2010, 8:25 pm

Kat, I'm delighted that you're interested in this item. I might be able to assist on the transport front since I'm travelling up the A1 this Friday, leaving Cambridge at whatever time will get me to Northumberland around 1pm. Peterborough or Leeds could be a drop-off point on the way, if it's any help...

Chris

Kat Manton · 2nd Sep 2010, 10:26 pm

Hi,

Chris is dropping it off tomorrow morning; so I get to play with SECAM at last

Jeffrey; that's good to know. The MythTV/Linux system produces RGB, though I've still to sort out something which will generate proper mixed sync from the H/V sync. Given the number of standards I've got the system to do, I think that's going to end up with a microprocessor in it.

If the colour-bar board is fitted, I presume it'd probably still need a mixed sync input? If so, that's not a problem as the Pye SPG I had from you would provide that (as would one of my vision mixers, I think.)

Any relevant diagrams you could provide would be appreciated; I'm looking at how deep that 1U case is and thinking there's probably a lot of bits inside... (less than my effects processor, but that'll be a subject for another thread...)

Cheers, Kat

ppppenguin · 2nd Sep 2010, 11:17 pm

Got a funny feeling the colour bar board needs mixed blanking. I may have a spare one around if your coder is lacking.

cmjones01 · 3rd Sep 2010, 5:38 am

The encoder will be starting its journey to Kat in half an hour or so. I had a quick look inside (the three modules pull out of edge connectors) and there's definitely a board piggybacked on to the 253 encoder module. Could that be the colour bar board?

ppppenguin · 3rd Sep 2010, 7:36 am

If there's a board piggybacked on the 253 coder module, about 8" x 3" that's the bar generator.

Kat Manton · 3rd Sep 2010, 10:34 am

Hi,

As it seemed likely to have the colour bar generator fitted, by the time Chris arrived, I'd brought the SPG and multistandard monitor downstairs.

Plugged sync and blanking in, connected monitor, set switches to likely-looking "this might produce colour bars" positions, flicked mains switch and colour bars immediately appeared

So it appears to work, I now have a source of SECAM (and an excuse to acquire more TV sets...)

Thanks, Chris, for the encoder and Jeffrey, for the information needed to get it going

Cheers, Kat

ppppenguin · 3rd Sep 2010, 10:41 am

I'll see what info I can dig out. I know I don't have the 253 or the pulse module. I've probably got the bar generator and PSU. There were several variants of the PSU so if you can post a photo of the module I can probably work it out. It comes with a minor warning. The 9-0-9 is done by a curious 2 transistor splitter from a stabilised 18V. If you draw too much from one side it gives up and can overheat the splitter transistors. I've used these modules for unbalanced work and had to fit a resistor to the other side.

Why 9-0-9 you ask? Because Mike Cox did much of his initial design work using a pair of 9V batteries

cmjones01 · 4th Sep 2010, 8:24 am

It was great to deliver the encoder and immediately see it working, with a cup of tea thrown in to the bargain. Thanks, Kat, and I'm very glad to see that it's gone to a good home.

30th Aug 2010, 3:32 pm	#1
cmjones01 Nonode Join Date: Oct 2008 Location: Warsaw, Poland and Cambridge, UK Posts: 2,677	Cox Electronics SECAM encoder Here's something that doesn't crop up every day. A Cox Electronics SECAM encoder. Ideal for the collector of French TV sets who wants to remain in the analogue domain. Plenty of adjustments to twiddle. I have no idea if it works or not: it was given to me free when I bought a frequency counter a few months ago. I'll never use it so someone else can have it. Free of charge in Cambridge, UK. Chris Attached Thumbnails

30th Aug 2010, 3:41 pm	#2
Kat Manton Retired Dormant Member Join Date: Jul 2005 Location: West Yorkshire, UK. Posts: 1,700	Re: Cox Electronics SECAM encoder Hi, I'd be interested in this, if it's possible to arrange posting it to me (and doesn't end up hideously expensive!) I'm interested in (analogue) television systems in general; a long-term aim is being able to encode and decode all of them. SECAM is on the list... (One of my monitors and possibly one TV will theoretically do SECAM though I've been unable to try them.) Cheers, Kat

31st Aug 2010, 11:38 pm	#3
AC/HL Dekatron Join Date: Nov 2003 Location: Heckmondwike, West Yorkshire, UK. Posts: 9,642	Re: Cox Electronics SECAM encoder If it can be got to Peterborough (Werrington) I can bring it to Leeds?

1st Sep 2010, 8:34 am	#4
ppppenguin Retired Dormant Member Join Date: Dec 2003 Location: North London, UK. Posts: 6,168	Re: Cox Electronics SECAM encoder If I remember correctly from days at Cox the 253 SECAM coder takes RGB inputs at 0.7Vp-p plus mixed sync. I don't think it needs any other pulses. If you're lucky it will have the colour bar sub-board installed - this wasn't always fitted. I don't have the circuits or any other data except possibly for the colour bar sub-board and the PSU.

1st Sep 2010, 8:25 pm	#5
cmjones01 Nonode Join Date: Oct 2008 Location: Warsaw, Poland and Cambridge, UK Posts: 2,677	Re: Cox Electronics SECAM encoder Kat, I'm delighted that you're interested in this item. I might be able to assist on the transport front since I'm travelling up the A1 this Friday, leaving Cambridge at whatever time will get me to Northumberland around 1pm. Peterborough or Leeds could be a drop-off point on the way, if it's any help... Chris

2nd Sep 2010, 10:26 pm	#6
Kat Manton Retired Dormant Member Join Date: Jul 2005 Location: West Yorkshire, UK. Posts: 1,700	Re: Cox Electronics SECAM encoder Hi, Chris is dropping it off tomorrow morning; so I get to play with SECAM at last Jeffrey; that's good to know. The MythTV/Linux system produces RGB, though I've still to sort out something which will generate proper mixed sync from the H/V sync. Given the number of standards I've got the system to do, I think that's going to end up with a microprocessor in it. If the colour-bar board is fitted, I presume it'd probably still need a mixed sync input? If so, that's not a problem as the Pye SPG I had from you would provide that (as would one of my vision mixers, I think.) Any relevant diagrams you could provide would be appreciated; I'm looking at how deep that 1U case is and thinking there's probably a lot of bits inside... (less than my effects processor, but that'll be a subject for another thread...) Cheers, Kat

2nd Sep 2010, 11:17 pm	#7
ppppenguin Retired Dormant Member Join Date: Dec 2003 Location: North London, UK. Posts: 6,168	Re: Cox Electronics SECAM encoder Got a funny feeling the colour bar board needs mixed blanking. I may have a spare one around if your coder is lacking.

3rd Sep 2010, 5:38 am	#8
cmjones01 Nonode Join Date: Oct 2008 Location: Warsaw, Poland and Cambridge, UK Posts: 2,677	Re: Cox Electronics SECAM encoder The encoder will be starting its journey to Kat in half an hour or so. I had a quick look inside (the three modules pull out of edge connectors) and there's definitely a board piggybacked on to the 253 encoder module. Could that be the colour bar board?

3rd Sep 2010, 7:36 am	#9
ppppenguin Retired Dormant Member Join Date: Dec 2003 Location: North London, UK. Posts: 6,168	Re: Cox Electronics SECAM encoder If there's a board piggybacked on the 253 coder module, about 8" x 3" that's the bar generator.

3rd Sep 2010, 10:34 am	#10
Kat Manton Retired Dormant Member Join Date: Jul 2005 Location: West Yorkshire, UK. Posts: 1,700	Re: Cox Electronics SECAM encoder Hi, As it seemed likely to have the colour bar generator fitted, by the time Chris arrived, I'd brought the SPG and multistandard monitor downstairs. Plugged sync and blanking in, connected monitor, set switches to likely-looking "this might produce colour bars" positions, flicked mains switch and colour bars immediately appeared So it appears to work, I now have a source of SECAM (and an excuse to acquire more TV sets...) Thanks, Chris, for the encoder and Jeffrey, for the information needed to get it going Cheers, Kat

3rd Sep 2010, 10:41 am	#11
ppppenguin Retired Dormant Member Join Date: Dec 2003 Location: North London, UK. Posts: 6,168	Re: Cox Electronics SECAM encoder I'll see what info I can dig out. I know I don't have the 253 or the pulse module. I've probably got the bar generator and PSU. There were several variants of the PSU so if you can post a photo of the module I can probably work it out. It comes with a minor warning. The 9-0-9 is done by a curious 2 transistor splitter from a stabilised 18V. If you draw too much from one side it gives up and can overheat the splitter transistors. I've used these modules for unbalanced work and had to fit a resistor to the other side. Why 9-0-9 you ask? Because Mike Cox did much of his initial design work using a pair of 9V batteries

4th Sep 2010, 8:24 am	#12
cmjones01 Nonode Join Date: Oct 2008 Location: Warsaw, Poland and Cambridge, UK Posts: 2,677	Re: Cox Electronics SECAM encoder It was great to deliver the encoder and immediately see it working, with a cup of tea thrown in to the bargain. Thanks, Kat, and I'm very glad to see that it's gone to a good home. Last edited by cmjones01; 4th Sep 2010 at 8:26 am. Reason: typos