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

greg_simons · 6th Apr 2019, 3:25 pm

As some of you know I'm restoring a 2000 ctv, does anyone out there have a modifications in production summary especially any knowledge about the later eht generator module with the finned heatsinks.
Greg.

HamishBoxer · 6th Apr 2019, 4:07 pm

Try Steve Pendleburys page,worth a look as he totally restored one I parted with years ago.

greg_simons · 6th Apr 2019, 4:35 pm

Hi Hamish,
Thanks for that, do you have a web address?.
Greg.

HamishBoxer · 6th Apr 2019, 5:00 pm

I will have a search. Not doing very well here, I am wondering whether it came under another website or link.

Have just PM,D Steve to see if he can furnish details of same, it was a great write up, plus there is a load of pdf's on this forum re restoration.

KeithsTV · 6th Apr 2019, 5:20 pm

Try this

http://www.oldtellys.co.uk/otindex.html

Keith

dazzlevision · 6th Apr 2019, 5:34 pm

I think the early 2000s used power transistors with a square casing in some positions, rather than T-03 style.

A significant “EHT gen mod kit” was offered by BRC to allow the use of higher rated power transistors (to improve reliabilty) and it involved (amongst other things) fitting a large “solenoid style” choke, similar to the one on the lower board of the 3000 line timebase module. Details were published in an edition of the “BRC Bulletin”.

HamishBoxer · 6th Apr 2019, 5:43 pm

Blow,I just the mail from Steve.Beaten to the post again!http://www.oldtellys.co.uk/otindex.html

vidjoman · 6th Apr 2019, 6:55 pm

I had a Marconi 2000 back in 1968 and it regularly destroyed a square transistor in the voltage regulator to the line stages/eht and after several replacements under guarantee, it failed on a Saturday evening and I replaced it with a 2N3055 which never failed again in the 7 years I owned the TV.

greg_simons · 6th Apr 2019, 7:07 pm

Quote:

Originally Posted by dazzlevision

A significant “EHT gen mod kit” was offered by BRC to allow the use of higher rated power transistors (to improve reliabilty) and it involved (amongst other things) fitting a large “solenoid style” choke, similar to the one on the lower board of the 3000 line timebase module. Details were published in an edition of the “BRC Bulletin”.

That sounds like the info I need to see, anyone got a copy?.
Greg.

greg_simons · 6th Apr 2019, 9:06 pm

More research suggests this is the info I'm after

Eht module modification kit p/n, 00m6 033
Any help most appreciated.
Greg.

dazzlevision · 6th Apr 2019, 9:36 pm

I have the relevant BRC Bulletin. I will scan and email it to you, but I’m away for a few days from tomorrow.

greg_simons · 6th Apr 2019, 9:52 pm

Hi dazzle
You're a star, i will await that info with much anticipation.
Greg.

greg_simons · 12th Apr 2019, 4:23 pm

I'm deeply indebted to dazzlevision for digging up the eht mod from the depths of antiquity, for anyone else interested I can post it here if required.
Just for completeness does anyone have any data or equivalents for the R2220 & R2210 transistors before I use some bu208's I've got handy, can't find any data on them at all.
Greg.

1100 man · 12th Apr 2019, 4:57 pm

Hi Greg,
I would certainly be interested in seeing the mods and it would be great if you could post them here.

Cheers
Nick

greg_simons · 12th Apr 2019, 5:57 pm

Hi nick
Yes of course, I need time on the main PC, try and get it done tomorrow.
Greg.

Mikey405 · 13th Apr 2019, 10:36 am

Hi Greg.

There is a useful article in a "Renovating the Rentals" article in Practical Television from many years back. If you don't mind a scanned-in copy then you can download one from here:

http://oldtechnology.net/documentation.html

(Number 14 in the list).

Thanks Greg.

Kind regards.

From Mike.

greg_simons · 13th Apr 2019, 1:17 pm

Thanks mikey
Don't mind a scanned copy at all, i remember reading this article at the time, crikey how time goes.
Work going well at the moment, pulling rotting bc107's out of the video panel like bad teeth, storage conditions must've been pretty bad.
Greg.

Samba1360 · 13th Apr 2019, 3:35 pm

Very interesting reading, I was an apprentice with Ketts starting in the summer of 1975, in all my years there I never once came across a BRC 2000 chassis, they were all 3000/3500 G8's, double sided GEC'S (arrrr) and Decca Bradfords, so looking forward to seeing this running.

greg_simons · 13th Apr 2019, 4:04 pm

Hi samba
Never did that many myself but its memory is indelibly etched in my mind, saw hundreds of three k's and the rest, work is progressing well but it may take a while, I'll probably have a working chassis in two or three months but the cabinet will take longer unless i get lucky with a spare or good chippy, joinery is not my forte.
Greg.

AC/HL · 13th Apr 2019, 5:12 pm

Once fettled, I ran mine for a few years without any real problems. The achilles heel was the tube. I replaced it twice with rebuilds, finally being unable to find one although I didn't try too hard.

6th Apr 2019, 3:25 pm	#1
greg_simons Octode Join Date: Jul 2004 Location: Evesham, Worcestershire, UK. Posts: 1,422	Thorn 2000 mods. As some of you know I'm restoring a 2000 ctv, does anyone out there have a modifications in production summary especially any knowledge about the later eht generator module with the finned heatsinks. Greg. __________________ Picture, sound?, DOOR.

6th Apr 2019, 4:07 pm	#2
HamishBoxer Dekatron Join Date: Aug 2007 Location: W.Butterwick, near Doncaster UK. Posts: 8,932	Re: thorn 2000 mods Try Steve Pendleburys page,worth a look as he totally restored one I parted with years ago. __________________ G8JET BVWS Archivist and Member V.M.A.R.S

6th Apr 2019, 4:35 pm	#3
greg_simons Octode Join Date: Jul 2004 Location: Evesham, Worcestershire, UK. Posts: 1,422	Re: Thorn 2000 mods. Hi Hamish, Thanks for that, do you have a web address?. Greg. __________________ Picture, sound?, DOOR.

6th Apr 2019, 5:00 pm	#4
HamishBoxer Dekatron Join Date: Aug 2007 Location: W.Butterwick, near Doncaster UK. Posts: 8,932	Re: Thorn 2000 mods. I will have a search. Not doing very well here, I am wondering whether it came under another website or link. Have just PM,D Steve to see if he can furnish details of same, it was a great write up, plus there is a load of pdf's on this forum re restoration. __________________ G8JET BVWS Archivist and Member V.M.A.R.S Last edited by HamishBoxer; 6th Apr 2019 at 5:12 pm.

6th Apr 2019, 5:20 pm	#5
KeithsTV Nonode Join Date: Aug 2007 Location: South Bradford, West Yorkshire, UK. Posts: 2,573	Re: Thorn 2000 mods. Try this http://www.oldtellys.co.uk/otindex.html Keith

6th Apr 2019, 5:34 pm	#6
dazzlevision Dekatron Join Date: Sep 2003 Location: Near Swindon, North Wiltshire, UK. Posts: 3,611	Re: Thorn 2000 mods. I think the early 2000s used power transistors with a square casing in some positions, rather than T-03 style. A significant “EHT gen mod kit” was offered by BRC to allow the use of higher rated power transistors (to improve reliabilty) and it involved (amongst other things) fitting a large “solenoid style” choke, similar to the one on the lower board of the 3000 line timebase module. Details were published in an edition of the “BRC Bulletin”.

6th Apr 2019, 5:43 pm	#7
HamishBoxer Dekatron Join Date: Aug 2007 Location: W.Butterwick, near Doncaster UK. Posts: 8,932	Re: Thorn 2000 mods. Blow,I just the mail from Steve.Beaten to the post again!http://www.oldtellys.co.uk/otindex.html __________________ G8JET BVWS Archivist and Member V.M.A.R.S

6th Apr 2019, 6:55 pm	#8
vidjoman Dekatron Join Date: Jun 2013 Location: East Sussex, UK. Posts: 3,326	Re: Thorn 2000 mods. I had a Marconi 2000 back in 1968 and it regularly destroyed a square transistor in the voltage regulator to the line stages/eht and after several replacements under guarantee, it failed on a Saturday evening and I replaced it with a 2N3055 which never failed again in the 7 years I owned the TV.

6th Apr 2019, 9:06 pm	#10
greg_simons Octode Join Date: Jul 2004 Location: Evesham, Worcestershire, UK. Posts: 1,422	Re: Thorn 2000 mods. More research suggests this is the info I'm after Eht module modification kit p/n, 00m6 033 Any help most appreciated. Greg. __________________ Picture, sound?, DOOR.

6th Apr 2019, 9:36 pm	#11
dazzlevision Dekatron Join Date: Sep 2003 Location: Near Swindon, North Wiltshire, UK. Posts: 3,611	Re: Thorn 2000 mods. I have the relevant BRC Bulletin. I will scan and email it to you, but I’m away for a few days from tomorrow.

6th Apr 2019, 9:52 pm	#12
greg_simons Octode Join Date: Jul 2004 Location: Evesham, Worcestershire, UK. Posts: 1,422	Re: Thorn 2000 mods. Hi dazzle You're a star, i will await that info with much anticipation. Greg. __________________ Picture, sound?, DOOR.

12th Apr 2019, 4:23 pm	#13
greg_simons Octode Join Date: Jul 2004 Location: Evesham, Worcestershire, UK. Posts: 1,422	Re: Thorn 2000 mods. I'm deeply indebted to dazzlevision for digging up the eht mod from the depths of antiquity, for anyone else interested I can post it here if required. Just for completeness does anyone have any data or equivalents for the R2220 & R2210 transistors before I use some bu208's I've got handy, can't find any data on them at all. Greg. __________________ Picture, sound?, DOOR.

12th Apr 2019, 4:57 pm	#14
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 would certainly be interested in seeing the mods and it would be great if you could post them here. Cheers Nick

12th Apr 2019, 5:57 pm	#15
greg_simons Octode Join Date: Jul 2004 Location: Evesham, Worcestershire, UK. Posts: 1,422	Re: Thorn 2000 mods. Hi nick Yes of course, I need time on the main PC, try and get it done tomorrow. Greg. __________________ Picture, sound?, DOOR.

13th Apr 2019, 10:36 am	#16
Mikey405 Octode Join Date: Jul 2006 Location: Solihull, West Midlands and Beaford, Devon Posts: 1,626	Re: Thorn 2000 mods. Hi Greg. There is a useful article in a "Renovating the Rentals" article in Practical Television from many years back. If you don't mind a scanned-in copy then you can download one from here: http://oldtechnology.net/documentation.html (Number 14 in the list). Thanks Greg. Kind regards. From Mike. __________________ G7TRF

13th Apr 2019, 1:17 pm	#17
greg_simons Octode Join Date: Jul 2004 Location: Evesham, Worcestershire, UK. Posts: 1,422	Re: Thorn 2000 mods. Thanks mikey Don't mind a scanned copy at all, i remember reading this article at the time, crikey how time goes. Work going well at the moment, pulling rotting bc107's out of the video panel like bad teeth, storage conditions must've been pretty bad. Greg. __________________ Picture, sound?, DOOR.

13th Apr 2019, 3:35 pm	#18
Samba1360 Triode Join Date: Mar 2011 Location: Horsham, West Sussex, UK. Posts: 29	Re: Thorn 2000 mods. Very interesting reading, I was an apprentice with Ketts starting in the summer of 1975, in all my years there I never once came across a BRC 2000 chassis, they were all 3000/3500 G8's, double sided GEC'S (arrrr) and Decca Bradfords, so looking forward to seeing this running.

13th Apr 2019, 4:04 pm	#19
greg_simons Octode Join Date: Jul 2004 Location: Evesham, Worcestershire, UK. Posts: 1,422	Re: Thorn 2000 mods. Hi samba Never did that many myself but its memory is indelibly etched in my mind, saw hundreds of three k's and the rest, work is progressing well but it may take a while, I'll probably have a working chassis in two or three months but the cabinet will take longer unless i get lucky with a spare or good chippy, joinery is not my forte. Greg. __________________ Picture, sound?, DOOR. Last edited by greg_simons; 13th Apr 2019 at 4:06 pm. Reason: grammar error

13th Apr 2019, 5:12 pm	#20
AC/HL Dekatron Join Date: Nov 2003 Location: Heckmondwike, West Yorkshire, UK. Posts: 9,642	Re: Thorn 2000 mods. Once fettled, I ran mine for a few years without any real problems. The achilles heel was the tube. I replaced it twice with rebuilds, finally being unable to find one although I didn't try too hard.