Aug 1967 Ferguson 3700: Another BRC/Thorn 2000 Chassis for the collection

Another simple find and fix. The line time-base system switch was non operation due to a deliberately snipped wire, a problem easily reversed.

This set continues to put up a fight, I just this minute turned the set on with the intention of doing some more work and yet again I have no sound! Installed an IF panel from another set and sound is restored.

I wonder if the 2nd Sound amp (VT5) had died yet again and if so why. Perhaps its the 1st sound amp this time? I take the if panel to the bench and investigate, will report back shortly.

Certainly being a little so and so.  ? 

Well VT4 & VT5 were OK, I checked R13 while I was at it. With the volume all the way up I can just faintly here some test card music. I'll do some live voltage checks next, this set is a real pain in the wotsit when it comes to trying to make progress in other areas of the set.

Edit: Just for the hell of it I replaced the two old BF173's with some new and now the sound is back. Uncertain whether the old transistors are failing under load or I have an intermittent problem, guess only time will tell. Back to the original task before this distraction, some setting up.

You haven't got some spark-gaps on the CRT base that are intermittently cracking over? Perhaps a gentle clean with IPA? 

Hi Crusty.  You mention the Radio rentals 720 sets or is it M720? The reason I ask is I think I may have one. It came in my possession in 1977 with some ex-rental 3000's. It had all the badges removed but I believe it to be and ex-rental from Radio Rentals. Its a Thorn 2000 chassis. I put a rebuilt tube in it in 1980 and my Dad used it up until he died in 1990. Do you have a picture of this model at all as I would love to know. It is unusual in it has a brown soft tube surround and the panel is brown similar to the Ferguson presentation and the controls are brown and have copper inserts. Never seen a Thorn 2000 before with this presentation.

Hurty

Posted by: @hurty

Do you have a picture of this model at all as I would love to know.

Hi Adrian, sadly no.

All that I have that proved the existence of the Baird badged Thorn 2000, are Radio Rental technical bulletins where they discuss stock faults.

Posted by: @hurty

You mention the Radio rentals 720 sets or is it M720?

No, they did not designate it the M720 but as I described, the 720, see below.

I suggest this numbering was because unlike the 700 and 710 series sets that did have the 'M' prefix, they were in house designed chasssis, the 2000 was not. Just as the model that replaced the 720 a few months later, was as Thorn 3000, it then carried the model number 8721,8722 and 8724 following the established Thorn 'Brand numbering'. All the other bulletins do reference 700/710 sets with the 'M' prefix. Though the M705 bucks all that because it as a GEC 2028 in disguise.

I covered all this in a thread 3 years ago now, you might find it interesting, though it gathered no interest the first time around.

https://www.radios-tv.co.uk/community/colour-television/early-radio-rentals-baird-ctvs/

It certainly looks like you might have the one and only Baird cabinet version of the Thorn 2000 in existence, a real rarity indeed. I've certainly never seen a 3700 with a brown Vinyl surround, brown knobs and copper inserts. I think I might have the Baird Badge knocking about. When I can get in the workshop I'll have a look.

Hi, It does seam unusual. If you have the badge I would love to know the dimensions and the hole spacing as you can see from the picture where it was mounted. I'd like a photo and wonder how you came across this badge??

Hurty

Posted by: @hurty

I'd like a photo and wonder how you came across this badge?

Hi, years ago I got a huge box full of TV knobs and in with it all were a lot of badges that had also been removed from various sets. There were all sorts of manufacturers and over the years they have come in use. I've managed to sort out a number of TVs whose badges were either missing or badly damaged. I'm sure I saw a couple of Baird in there but cannot get access at present due to the workshop being in a mess due to an extension build. Once I can get in there after the works, I will find and take a photo.