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Old 6th Nov 2023, 2:25 pm   #1
Colourstar
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Default 1962 Baird 604

I recently acquired this unusual set as it's from one of my favourite design periods for televisions. Its a Baird 604, dating from October 1962 according to the stamp inside the cabinet. It has provision for attaching legs and the tapered side profile was a design trend at the time also employed to great effect on the Ferguson 705T 'Senator'. The cabinet has the typical super hi-gloss polyester finish that's prone to cracking in the heat (which this one has, on top).

This is a 19" model with the crt behind a moulded plastic implosion screen. The set appears to be '625 ready' - there looks to be a system switch inside which presumably alters the timebase, although none of the user controls appear to act on the cam to make it move. There's nothing on the receiver side relating to UHF reception although a hole in the lower portion of the speaker grille, covered by the fabric, suggests a place where a UHF tuner control would emerge. This of course was a difficult period for manufacturers when there was such uncertainty over the future of line standards in the UK.

I don't think many Baird sets from this period survive. I'm guessing Radio Rentals would either rent you one of these or you could buy one outright.

Attached are a few photos taken just before my camera battery conked out.

Steve
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Old 6th Nov 2023, 2:37 pm   #2
dazzlevision
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Default Re: 1962 Baird 604

These sets were designed with 405-625 conversion in mind. Here's a photo of the basic UHF converter electronics and another of it in a plinth unit designed to fit below the TV, in models with no space allocated for it within the original cabinet.
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Old 6th Nov 2023, 2:55 pm   #3
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Default Re: 1962 Baird 604

How fascinating. Those fiddly tuner drive cords are always fun. That plinth must be incredibly rare! I wonder how many of these convertible sets, not just Baird, were actually converted and how successful the conversion kits actually were (in terms of performance). By the time BBC2 arrived it was probably tempting to go for one of the newer dual-standard models anyway, such as the Bush TV125 or early Pye 11U series sets.

I'm sure a lot of 'unconverted convertible' TVs were relegated to second-set duties and remained 405-only for the rest of their working lives.
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Old 6th Nov 2023, 3:09 pm   #4
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Default Re: 1962 Baird 604

Quote:
Originally Posted by Colourstar View Post
That plinth must be incredibly rare! I wonder how many of these convertible sets, not just Baird, were actually converted and how successful the conversion kits actually were (in terms of performance). By the time BBC2 arrived it was probably tempting to go for one of the newer dual-standard models anyway, such as the Bush TV125 or early Pye 11U series sets.
Baird TVs and UHF converters are pretty rare, as most were rented (although Radio Rentals did sell Baird TVs as well).

As you suspected, not many "convertible" TVs ever had the conversion kits fitted. That's why so many converter kits ended up with Mr Sylvester of Manor Supplies in West Hampstead, London - a regular advertiser in Practical Television/Television magazine in days gone by. I was a regular visitor to his shop. My particular interest is in TVs of the 1960s, especially the convertible ones.

The performance of converted TVs was very variable. Some manufacturer's kits worked well, even allowing for the low gain/high noise figure of a valve UHF tuner. The kits that worked well usually had three vision IF stages for UHF working, which made them more sensitive.
My favourite is the Murphy Astra converter, which was a plinth type unit.
My least favourite was the Thorn 800/850 converter, which only had two vision IF stages and required the fitting of a new back cover for the TV after the 625 IF (wired chassis) converter unit was fitted!

I think Labgear must have saved the day for valve UHF tuners with their masthead and back of the TV UHF preamplifiers, when transistors capable of working at UHF frequencies became available (AF186, AF139 etc).
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Old 6th Nov 2023, 3:40 pm   #5
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Default Re: 1962 Baird 604

Quote:
Originally Posted by dazzlevision View Post
Quote:
Originally Posted by Colourstar View Post
That plinth must be incredibly rare! I wonder how many of these convertible sets, not just Baird, were actually converted and how successful the conversion kits actually were (in terms of performance). By the time BBC2 arrived it was probably tempting to go for one of the newer dual-standard models anyway, such as the Bush TV125 or early Pye 11U series sets.
Baird TVs and UHF converters are pretty rare, as most were rented (although Radio Rentals did sell Baird TVs as well).

As you suspected, not many "convertible" TVs ever had the conversion kits fitted. That's why so many converter kits ended up with Mr Sylvester of Manor Supplies in West Hampstead, London - a regular advertiser in Practical Television/Television magazine in days gone by. I was a regular visitor to his shop. My particular interest is in TVs of the 1960s, especially the convertible ones.

The performance of converted TVs was very variable. Some manufacturer's kits worked well, even allowing for the low gain/high noise figure of a valve UHF tuner. The kits that worked well usually had three vision IF stages for UHF working, which made them more sensitive.
My favourite is the Murphy Astra converter, which was a plinth type unit.
My least favourite was the Thorn 800/850 converter, which only had two vision IF stages and required the fitting of a new back cover for the TV after the 625 IF (wired chassis) converter unit was fitted!

I think Labgear must have saved the day for valve UHF tuners with their masthead and back of the TV UHF preamplifiers, when transistors capable of working at UHF frequencies became available (AF186, AF139 etc).
Anyone got a photo of one, I haven’t seen one for so long all I remember is a black plastic box?
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Old 6th Nov 2023, 3:56 pm   #6
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Default Re: 1962 Baird 604

Interesting receiver, never saw many converted sets, the valve uhf tuner units were fairly short lived and not all that good, my favourite was the STC VC1 chassis range, by the time i got round to converting mine to uhf a transistorised tuner was available on a custom bracket, just plugged in and that was it.
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Old 6th Nov 2023, 5:33 pm   #7
steve1010uk
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Default Re: 1962 Baird 604

I remember the Thorn 800 sets with the convertor fitted, at the ex rental warehouse i then worked at we called them "humpbacks" they had hardly any gain, ok if you lived next to Emley moor and had an 18 element aerial not much good otherwise, most were sold as 405 only to avoid problems.
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Old 6th Nov 2023, 6:23 pm   #8
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Default Re: 1962 Baird 604

Here's a photo of one, without the valves (it's unused - as most were!):
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Old 6th Nov 2023, 6:56 pm   #9
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Default Re: 1962 Baird 604

The sets I remember fitting conversion kits to in fairly large quantities were the 19" Murphy models.
This was the complete tuner/I.F in a wooden plinth which was fitted under the cabinet.
That also had a long drive-cord system for tuning. Not particularly user-friendly, and there was quite a long delay when switching from 405 to 625, as the valve heaters in the plinth unit warmed up!

David.
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Old 7th Nov 2023, 12:32 pm   #10
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Default Re: 1962 Baird 604

Quote:
Originally Posted by Colourstar View Post
The set appears to be '625 ready' - there looks to be a system switch inside which presumably alters the time base, although none of the user controls appear to act on the cam to make it move. There's nothing on the receiver side relating to UHF reception although a hole in the lower portion of the speaker grille, covered by the fabric, suggests a place where a UHF tuner control would emerge.
We had a similar situation in France when it was decided that the 2nd programme (and future ones) would be in 625 lines and not in 819 lines like the first.
Sets produced from 1961 onwards had to be dual standard 819/625 lines and have a provision to add a UHF tuner (some where fully equipped but not all).
The problem was simpler than in UK because we continued to use positive video modulation and AM sound and the IF bandwidth could be reduced to fit the new channels (8 MHz instead of 14).

For 819 lines only sets produced before 1961, there were some "set top box" type adapters which included a tuner, a specific barrett reducing the IF bandwidth and components to switch the line time base.
Of course it needed internal connections inside the TV which could not be done by a standard user.
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Old 4th Feb 2024, 10:52 pm   #11
Laurence Smith
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Default Re: 1962 Baird 604

This thread caught my attention as I have the 23" Baird 606 with the UHF conversion kit fitted. It's been in storage for 10 years or so but I retrieved it over the weekend and I attach some photos in case anyone is interested.

I originally got it from my aunt around 20 years ago who would have brought it down from London with her to Devon when she moved there in 1971. I've asked her about it recently, but she doesn't recall whether she originally rented it or where she purchased it.

When I powered it up 20 years ago I remember getting UHF sound but it would only show a reduced size raster on 405 only, which faded out when the brightness control was advanced, so possibly has a failed LOPT. The knobs are not with the set at the moment, but I do have them somewhere.
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