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Old 24th Jul 2016, 2:58 pm   #121
FERNSEH
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Default Re: Earliest BBC2 Sets?

I believe British Relay had commissioned a "dry" line output transformer for the company's Murphy Astra receivers. A cable version of the V659 series was made by Murphy for British Relay.

DFWB.
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Old 24th Jul 2016, 5:51 pm   #122
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Default Re: Earliest BBC2 Sets?

'Direct TV Replacements' also produced an open version of the Murphy transformer. I don't understand why Murphy continued with the oil filled can as late as 1962, especially with all the leakage problems they had encountered with it. I believe the idea first appeared around 1950 with the V178. The 'Murphy Service News' service newsletter to dealers around the 1961-62 period lists many modifications to attempt to sort out service niggles that dealers were experiencing with the 600 and 700 series.
The first common sound and vision IF amplifier was a 6F23, not a vari u valve requiring an internal preset gain control labelled 'cross modulation' in the manual. I remember severe overload on channel 1 that had to be attenuated.
Line fold over on the left was another problem on 405 that caused the local Murphy dealer 'Pooles Radio' 4 High Street Merton some annoyance. He hated them! By the time all these problems were sorted the take over with Rank was complete and the attractive series faded fast in the mid 60's.
Scan shows the full 1962 range of 700 series models.
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Old 25th Jul 2016, 2:07 am   #123
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Default Re: Earliest BBC2 Sets?

An interesting thread this.

I recall the Bush TV125 that my parents bought brand new, which was soon converted to receive BBC2 with a manufacturers kit (with a valve type PC88/86 tuner), and I also recall the TV125U which I obtained not that many years afterwards as a gift from someone "to use for parts".

Mine had an almost useless CRT (which, oddly, was the original Mullard one) but a germanium based (AF186) factory fitted UHF tuner and a PC97 based VHF tuner (the old chap's one being a PCC89 one).

After I fitted a replacement second hand crt to mine it easily outran the old fella's set for gain on all bands, which was a problem for me as that was still the family telly, even though he'd spent a small fortune on replacement tuner valves :-(
(We did live towards the fringe area for Sutton Coldfield.)

Yep, we ended up making a swap.

Ironically, it wasn't the duff crt that had caused mine to be given away as parts, but the plastic "wand" in the VHF tuner which had snapped causing loss of all VHF channels. Easily cured using a biro spring and a bit of coax braiding soldered to keep it all in place.

Last edited by DangerMan; 25th Jul 2016 at 2:12 am.
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Old 25th Jul 2016, 10:59 am   #124
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Default Re: Earliest BBC2 Sets?

The first set we had that was capable of receiving BBC2 was, I think an HMV rented from Robinson Rentals,later Granada. I don't ever remember seeing BBC2 on it though.
The first one I got to play with was an STC VC2 I got it without the UHF tuner but it was easy to fit a rotary UHF tuner, transistorised, and it worked extremely well here in Coventry. Picking up BBC2 on just a length of wire as an aeriel.
Steve
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Old 25th Jul 2016, 11:55 am   #125
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Default Re: Earliest BBC2 Sets?

Hello,

The first TV set my parent's bought that was "convertible to dual standard operation" was a Decca model DR41 (in 1963). It was made by Ferguson (Thorn) for Decca Radio & Television and used the Thorn 850 convertible chassis.

The Thorn 800 and 850 convertible chassis are factory fitted with:

a 405-625 line timebase,
switching provision for the 405/625 video drive to CRT and
the 405/625 AM/FM sound.

The factory fitted 405-625 switching consists of a rotary "wafer" type switch and a linear switch (as used in most dual standard TV receivers). These two switches are mechanically linked and operated by a rotary knob on the left hand side of the cabinet (when viewed from the front).

The IF amp/sound detector and audio output/video detector and amp and sync separator circuitry is 405 only and contained on a single large printed panel, mounted above the CRT neck and tilted to face rearwards at an angle of approximately 45 degrees. All connections to this PCB are via wire wrap pins. The chassis design employs direct line sync.

A B9A socket is fitted on the main chassis and this can be used for two purposes:

adding a line flywheel sync unit (for weak signal areas) or
connecting a 625 converter IF/video/sound detector unit (hand wired chassis).

Towards the end of the 1960s, after I had developed an interest in radio and TV electronics, I did write to Decca R&TV spares department (located at Ingate Place, Queenstown Road, London), asking for a quote for the conversion kit. They replied that they were priced at fifteen Guineas (i.e. 15, 15 shillings) - rather a lot in those days, so I didn't order one.

Dual standard conversion of the Thorn 850 convertible chassis results in a particularly cumbersome set-up. The 625 IF amplifier sits behind the existing 405 IF/sound output/video amp/sync separator printed panel and thus requires a modified back cover to be fitted. The cabinet is already pre-drilled to accommodate a UHF tuner and UHF aerial input socket (side mounted in the case of the DR41). All connections to the main chassis are by a B9A plug, push on connectors. Several factory fitted wire links (mainly on the 405-625 changeover switch) have to be cut.

The converted receiver wasn't a good performer on UHF/625, due to the high noise figure and low gain of the valve UHF tuner and the relatively low gain of the (EF183/EF184) 625 IF amplifier (as the UHF tuner's IF output wasn't first routed via the VHF tuner's mixer stage, in order to provide additional IF gain on 625). However, Ferguson did offer a small 625 single transistor IF preamplifier unit that could be clipped onto the 625 converter chassis, in order to increase sensitivity.

A couple of years later, when BBC1, BBC2 and ITV were all available on UHF/625, I acquired a nice 19" Ferguson 3618, which used the Thorn 850 dual standard chassis. I fitted a transistorised UHF tuner, in order to improve reliability, signal to noise ratio and sensitivity. This was then the main family viewing set until the arrival of our first colour TV (a 22" Philips G8, early "520" series models version).

I then proceeded to modify the Decca DR41 for UHF/625 only operation, by fitting a Pye 40F series integrated transistor UHF/VHF pushbutton tuner (with a Pye model 40F escutcheon, to make it look neat) where the front facing loudspeaker was. I also fitted the correct Thorn 625 IF unit. Both of these units were obtained from that Aladdin's Cave - Manor Supplied of West Hampstead, London).

I modified the 405 IF PCB to leave only the sync separator (EF80) and sound output (PCL82) circuitry. The other areas of the PCB were cut away, leaving sufficient room to fit the Thorn 625 IF chassis where the 405 IF PCB used to be. This meant the original back cover could still be used. I had to ensure correct heater chain current and fit a smaller loudspeaker, plus provide a low voltage dc supply for the Pye tuner. The modified set worked quite well and was my bedroom TV for a few years until I bought an ex-rental 19" Thorn 2000 CTV for 11 in 1976.

Regards,

Dazzlevision
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Old 25th Jul 2016, 1:12 pm   #126
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Default Re: Earliest BBC2 Sets?

the mention of the switch being on the left hand side of the cabinet and also the main if etc board being mounted above the tube and at an angle has reminded me of the HMV we rented which had these same features. I had forgotten them until reading Dazzlevisio's post.
Steve
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Old 26th Jul 2016, 9:19 am   #127
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Default Re: Earliest BBC2 Sets?

Quote:
Originally Posted by Nicklyons2 View Post
The earliest specimen I saw, at the time, was the Murphy V659. A lovely looking thing with a VHF tuner which resembled a pre-sliced pie. The big BUT is it was a 'convertible to' set and I never saw one which had been converted... has anyone?
Hello Nick,

I have seen a converted Murphy Astra series set, the V753 (Astra 2 chassis). This is the 23" CRT model, without VHF/FM radio facilities or ultrasonic remote control. Unlike the Astra 1 series, the Astra 2 chassis had the Octal valve holder factory fitted at the bottom, ready for connection of the UHF/625 converter plinth that sat under the TV. The Astra 1 chassis required the fitting of an additional section of 405-625 system switch and the Octal converter socket.

I acquired the unconverted set in the early 1970s, with its original magazine rack style stand. I then obtained a UHF converter plinth from Manor Supplies in London and fitted it.

The converted set worked very well and (despite the Mullard/Philips valve UHF tuner fitted) was quite sensitive, having 3 x 6F23s in the 625 IF amplifier. The display of Test Card F was very crisp and all but the bottom (5.25MHz?) frequency grating was clearly defined. I subsequently sold it.

Much more recently, I acquired a V789 (19" Astra 2 chassis, with VHF/FM radio), which I have restored. I also have the correct Murphy 19" UHF/625 converter plinth (again, from Manor Supplies - many years ago), but have yet to fit it. Sadly, I do not have the Murphy magazine rack stand for it.

I do like the look of these sets (both the Astra 1 and 2 series). The Astra 2 range looked rather more "modern" than its V6xx series predecessors. The models with VHF/FM radio also had line gated vision AGC and the VHF radio circuit used a double frequency conversion system at IF, plus AFC and the resulting sound quality (and freedom from tuning drift) was much better than other TV+FM radio sets from other manufacturers.

An earlier post in this thread commented on the lack of a variable-mu valve in the first vision IF stage and the need to adjust the "cross modulation" slider preset where a very strong local signal was present. Whilst this is true, many other chassis of the same era with a vari-mu valve in the first vision IF stage also had a similar preset fitted (e.g. Bush TV125 - EF85 and STC/K-B VC1/2/3 - EF183)

Regards,

Dazzlevision

Last edited by dazzlevision; 26th Jul 2016 at 9:24 am. Reason: Added text.
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Old 28th Jul 2016, 2:28 pm   #128
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Default Re: Earliest BBC2 Sets?

Dave, thanks for your info on the Murphy Astras, not only have I never seen a 23" one I'd never realised an FM version was available as well; I clearly missed a lot! I always loved the magazine rack stands though, much better than the gangly legs which supported many sets of the era. My excuse is that the 'home' area was not particularly a wealthy one and luxuries such as FM radios and 'huge' TVs were very rare. In fact the local farmer's TV128 was the first 23" set I ever saw and, AFAIK was the first large screen set in the town (it was in the worker's communal lounge).

And whilst on the subject of that chassis post #123 informs me of something else I've never seen a factory fitted transistor tuner in a TV125, 135s yes - it must have been right at the end of production. Quite a few I've known had the PC97 VHF tuner though.
To go full circle; how ugly were the Murphy TV135 clones when compared to the Astra series, particularly with the Fenbridge Guards fitted.
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Old 28th Jul 2016, 3:22 pm   #129
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Default Re: Earliest BBC2 Sets?

Quote:
Originally Posted by Nicklyons2 View Post
Dave, thanks for your info on the Murphy Astras, not only have I never seen a 23" one I'd never realised an FM version was available as well; I clearly missed a lot! I always loved the magazine rack stands though, much better than the gangly legs which supported many sets of the era.

To go full circle; how ugly were the Murphy TV135 clones when compared to the Astra series, particularly with the Fenbridge Guards fitted.
Hello Nick,

Glad the info was informative. I agree with you that the Murphy magazine rack style of stand was much more attractive than four screw-in leads and more stable and useful.

I also agree that the Murphy versions of the Bush TV135 series sets, with Fenbridge guards, rather than direct vision CRTs were much less attractive and impaired the displayed picture. They made the same mistake in the Murphy equivalents to the Bush TV141/TV148 sets (i.e. V159 & V153).

Regards,

Dazzlevision
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Old 29th Jul 2016, 10:08 am   #130
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Default Re: Earliest BBC2 Sets?

When we got married in '63 we had a Philips 'T Vette' secondhand of course (nearly everything we had was) it was quite a modern set compared with some dual standard sets that I had worked on and gave a very good account of itself, the gain on both systems was good and we could pick up stations from far and wide, our location no doubt helped though.

Peter
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Old 29th Jul 2016, 10:36 am   #131
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Default Re: Earliest BBC2 Sets?

This was my first BBC2 receiver:

http://www.radiomuseum.org/r/hismasters_1845.html

I "converted" it, the picture width was lacking so I reduced the picture height to get the right ratio, can't remember the exact details of the mods I did but I retained most of the original IF circuitry and it tweeked up, not perfect but was ok from a distance, it was my bedroom telly.

Lawrence.
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Old 29th Jul 2016, 3:09 pm   #132
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Quote:
Originally Posted by Peter.N. View Post
When we got married in '63 we had a Philips 'T Vette' secondhand of course (nearly everything we had was) it was quite a modern set compared with some dual standard sets that I had worked on and gave a very good account of itself, the gain on both systems was good and we could pick up stations from far and wide, our location no doubt helped though.

Peter
Hello Peter,

Is "'63" a typo?

I don't think the Philips T-Vette (if you mean the UK made 11" 240/12V 405/625 set - model 11TG190AT) was made until 1965 at the earliest.

Regards,

Dave
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Old 29th Jul 2016, 3:12 pm   #133
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Quote:
Originally Posted by pwdrive View Post
This was my first BBC2 receiver:

http://www.radiomuseum.org/r/hismasters_1845.html

I "converted" it, the picture width was lacking so I reduced the picture height to get the right ratio, can't remember the exact details of the mods I did but I retained most of the original IF circuitry and it tweeked up, not perfect but was ok from a distance, it was my bedroom telly.

Lawrence.
Hello,

This reminds me of getting a "just about watchable" BBC2 picture and sound, by feeding a valve UHF tuner's IF output into the aerial socket of a 17" Ekco VHF/405 only set (made around 1957) and turning up the contrast control sufficiently to invert the picture and make it a positive image.

IIRC, this was mentioned as possible in an issue of Practical Television.....?

Dazzlevision
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Old 29th Jul 2016, 5:37 pm   #134
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Default Re: Earliest BBC2 Sets?

Scan off plinth fitting instructions to 700 series. John.
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Old 29th Jul 2016, 6:05 pm   #135
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Default Re: Earliest BBC2 Sets?

Quote:
Originally Posted by dazzlevision View Post
This reminds me of getting a "just about watchable" BBC2 picture and sound, by feeding a valve UHF tuner's IF output into the aerial socket of a 17" Ekco VHF/405 only set (made around 1957) and turning up the contrast control sufficiently to invert the picture and make it a positive image.
I was in the trade at the time (1966) I did the "conversion" over a period of a couple of weeks during dinner breaks at the firms workshop where I worked, as said I can't remember the details to well but I grafted a UHF tuner in and modified various bits/circuits, I didn't fit any kind of standard 625 IF strip from dual standard set, I think I changed some of the IFT's for wider bandwidth ones and cobbled up an FM detector etc etc.

Had that as my BBC2 bedroom telly for a couple of years.

Happy days.

Lawrence.
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Old 30th Jul 2016, 11:05 am   #136
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Quote:
Originally Posted by dazzlevision View Post
Is "'63" a typo?
Well it was definitely '63 when we got married and in the 7 years we lived there we had a set that looked like it, knobs vertical row r/h end, separate VHF/UHF tuners. We certainly had it during the time we lived there and its unlikely we would have been able to afford one that new - but its possible of course, could have been a trade in, I will see if my wife remembers. Maybe I have the set wrong.

Peter
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Old 31st Jul 2016, 7:39 pm   #137
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Question Re: Earliest BBC2 Sets?

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Please: at the bottom of the stack (below the set that's switched on), what's that set?
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Old 31st Jul 2016, 8:24 pm   #138
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Default Re: Earliest BBC2 Sets?

Looks like a Bush TV 125, possibly a Murphy same chassis, can't make my mind up if the buttons are round or square.
Just see an Ekco T418 on the left, UHF tuner fitted.
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Old 31st Jul 2016, 9:25 pm   #139
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Quote:
Originally Posted by Nuvistor View Post
Looks like a Bush TV 125, possibly a Murphy same chassis, …
Yep, there's one at Bush TV125 Dual Standard televison 1964. | 1964 Bush dual st… | Flickr. The more I think about Bush designs of the 1950s and 1960s, the more I love them.

Thanks
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Old 1st Aug 2016, 9:24 am   #140
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Hello,

In the early 1970s, I converted a Murphy V739 to UHF/625 only operation. The V739 is a 19" Astra Mk 2 set, rental model, without pushbutton tuning - just a large round knob to change channels, coupled directly to the VHF tuner's turret.

I stripped out the VHF tuner, 405 IF stages and 405 video amp. I then fitted the two small PCBs from a gutted Murphy UHF converter plinth in their place, plus a varicap diode UHF tuner (ELC1043) and 30V/12V power supply (derived from the HT line). I also fitted a 4 pole wafer switch that was operated by the existing channel selector knob and shaft, to control the Varicap tuner.

Finally, I stripped out all the system switching (factory fitted) on the main chassis and the Octal converter socket, wiring the set for 625 only operation.

The result was a very good 625 picture and sound (the tired original Mazda CRT had previously been replaced by a Mullard AW47-91).

Unfortunately, I didn't keep the set.

Regards,

Dazzlevision
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