Thorn 2000 mods. - Page 2 - UK Vintage Radio Repair and Restoration Discussion Forum

its ur aerial · 14th Apr 2019, 8:06 pm

Its many years since I saw a BRC 2000, but I don't recall it fitted with any thing other than a 2N3055`s.
In fact I worked with some one who used them as a supply source for the PA in his MW Pirate TX. Not me Guv......

AC/HL · 14th Apr 2019, 10:57 pm

They were Texas devices with an R prefix, as were the following 3000 series. R2010 comes to mind.

greg_simons · 18th Apr 2019, 8:49 am

Hi folks
Well, work progresses well, most of the scan and power modules cleaned up and rebuilt, the bottom boards where the water has collected are more problematic, lots of rotting transistors literally falling out though it's no great problem, one thing that is though is a damaged T1 burst transformer on the chrominance module, can anyone post or email me with a couple of hi res pictures of it so that i can work out how it goes back together, or one off a scrap board.
Greg.

1100 man · 20th Apr 2019, 11:18 pm

Hi Greg,
I've dug out the chroma board from the depths of my 2000 and had a look at it. It's remarkably clean and has a good sprinkling of Callins electrolytics! At least my transistors aren't legless!

T1 consists of two windings each of a dozen or so turns (I'll count them if you want) wound on a rectangular former with two small holes in it. The primary winding is wound with green wire and the secondary with copper coloured wire.

The primary (green) side has two pins and is connected between VT2 collector and R10/C10 junction.

The secondary (copper colour) has three pins. The winding connects to the outer two pins. The centre pin goes to the 2pf cap.

Hope that might help, but if not, let me know and I'll see if I can do better!

Cheers
Nick

greg_simons · 21st Apr 2019, 12:05 am

Hi nick
That info was just what I needed, I have the windings the right way round, my transformer is slightly different in that the windings are on the inside if you like, both holes are used but the photo's confirm that my guesswork was correct and I have the green winding as the primary.
As for legless transistors there's lots, mainly the bf115 and bc107 devices, even the if board which looks at first sight amazingly clean has several rotted devices, so langrex are going to be kept quite busy supplying small packages of new semiconductors of various sorts.
I have four good rebuilt eht modules now plus frame and line scan boards, the power regulator and power supply boards are halfway done, I have a little help in the form of the cat who sleeps nearby and supervises operations.
Greg.

Welsh Anorak · 22nd Apr 2019, 11:58 am

I'm reading this with great interest Greg - you're just what the old thing needed! I'd never have been able to devote this much time to it.
Glad you got the transformer worked out.
I have the BBC mod sheet for raster correction when you need it - which might be a while yet...

AC/HL · 25th Apr 2019, 4:01 pm

I'm having a belated post move sort out, and have come across the 2000 installation manual (not service, I gave that away some time ago). Adjustments, convergence etc.
PM your address if you want it Greg.

14th Apr 2019, 8:06 pm	#21
its ur aerial Hexode Join Date: May 2009 Location: Ryde, Isle of Wight, UK. Posts: 419	Re: Thorn 2000 mods. Its many years since I saw a BRC 2000, but I don't recall it fitted with any thing other than a 2N3055`s. In fact I worked with some one who used them as a supply source for the PA in his MW Pirate TX. Not me Guv...... __________________ Life is not Hollywood, life is Cricklewood.

14th Apr 2019, 10:57 pm	#22
AC/HL Dekatron Join Date: Nov 2003 Location: Heckmondwike, West Yorkshire, UK. Posts: 9,642	Re: Thorn 2000 mods. They were Texas devices with an R prefix, as were the following 3000 series. R2010 comes to mind.

18th Apr 2019, 8:49 am	#23
greg_simons Octode Join Date: Jul 2004 Location: Evesham, Worcestershire, UK. Posts: 1,421	Re: Thorn 2000 mods. Hi folks Well, work progresses well, most of the scan and power modules cleaned up and rebuilt, the bottom boards where the water has collected are more problematic, lots of rotting transistors literally falling out though it's no great problem, one thing that is though is a damaged T1 burst transformer on the chrominance module, can anyone post or email me with a couple of hi res pictures of it so that i can work out how it goes back together, or one off a scrap board. Greg. __________________ Picture, sound?, DOOR.

20th Apr 2019, 11:18 pm	#24
1100 man Octode Join Date: Apr 2016 Location: Ventnor, Isle of Wight, & Great Dunmow, Essex, UK. Posts: 1,377	Re: Thorn 2000 mods. Hi Greg, I've dug out the chroma board from the depths of my 2000 and had a look at it. It's remarkably clean and has a good sprinkling of Callins electrolytics! At least my transistors aren't legless! T1 consists of two windings each of a dozen or so turns (I'll count them if you want) wound on a rectangular former with two small holes in it. The primary winding is wound with green wire and the secondary with copper coloured wire. The primary (green) side has two pins and is connected between VT2 collector and R10/C10 junction. The secondary (copper colour) has three pins. The winding connects to the outer two pins. The centre pin goes to the 2pf cap. Hope that might help, but if not, let me know and I'll see if I can do better! Cheers Nick Attached Thumbnails

21st Apr 2019, 12:05 am	#25
greg_simons Octode Join Date: Jul 2004 Location: Evesham, Worcestershire, UK. Posts: 1,421	Re: Thorn 2000 mods. Hi nick That info was just what I needed, I have the windings the right way round, my transformer is slightly different in that the windings are on the inside if you like, both holes are used but the photo's confirm that my guesswork was correct and I have the green winding as the primary. As for legless transistors there's lots, mainly the bf115 and bc107 devices, even the if board which looks at first sight amazingly clean has several rotted devices, so langrex are going to be kept quite busy supplying small packages of new semiconductors of various sorts. I have four good rebuilt eht modules now plus frame and line scan boards, the power regulator and power supply boards are halfway done, I have a little help in the form of the cat who sleeps nearby and supervises operations. Greg. __________________ Picture, sound?, DOOR.

22nd Apr 2019, 11:58 am	#26
Welsh Anorak Dekatron Join Date: Apr 2005 Location: North Wales, UK. Posts: 6,916	Re: Thorn 2000 mods. I'm reading this with great interest Greg - you're just what the old thing needed! I'd never have been able to devote this much time to it. Glad you got the transformer worked out. I have the BBC mod sheet for raster correction when you need it - which might be a while yet... __________________ Glyn www.gdelectronics.wales

25th Apr 2019, 4:01 pm	#27
AC/HL Dekatron Join Date: Nov 2003 Location: Heckmondwike, West Yorkshire, UK. Posts: 9,642	Re: Thorn 2000 mods. I'm having a belated post move sort out, and have come across the 2000 installation manual (not service, I gave that away some time ago). Adjustments, convergence etc. PM your address if you want it Greg.