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Early Radio Rentals (Baird) CTV's

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crustytv
(@crustytv)
Posts: 11867
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Topic starter
 

As you all probably know I'm a big fan of Baird (Radio Rentals) sets with four of their colour sets in the collection. I've been searching, trying to figure out if there are any differences between the models other than they're in different veneered cabinets and sport different masks. 

The following might be of interest on early CTV Baird(Radios Rentals) sets :-

1967-1968

The 700 (RCA inspired) chassis

The 700 manual mentions all these early CTV sets

  • M701/T
  • M701/W
  • M701/W
  • M702/T
  • M702/WP
  • M703
  • M704
  • M707

All developing an 8kV pulse from the lopt overwind into an EHT tripler with thermionic EHT shunt stabilisation.

The latter two M704 and M707 being the rarest of the Baird's colour TV's, as far as I'm aware none survive but would love to be proved wrong. They were monstrously large being combined 25" colour TV with radio and hi-fi. Top lifted to reveal amplifier, stereo radio and transcription turntable.Large speakers each end of the colonial style cabinet.

Note:

  • M705

This is not mentioned in the 700 series chassis manual because the M705 was basically a re-badged GEC 2028. It was the lowest priced colour TV of 1967.

  • M706 ? - I've never found any mention

1968-1969

The 710 series chassis

  • M718

The 710 manual makes no reference to the M708 only the M718. The M718 ( and apparently the M708) again developing an 8kV pulse from the lopt overwind into an EHT tripler but now a VDR stabilises the EHT and its current.  With the thermionic stabilisation now gone ( and the scary X-ray risk)  this makes way for the new focus arrangement with the tripler moving further back on the chassis.

Also another interesting feature where it differs from the 700 is the use of an integrated circuit device, the RCA CA3034V1. It was used for all the signal processing components with the exception of the phase-detector transformer and contained within a 10 pin TO-5 can. Quite likely this is the earliest use of an i.c. in a British CTV set.

ca3006ic

The convergence panel being detachable, it can be swung around and hooked to the side chassis member for ease of adjustment.


  • M708

This set appears to fall into the void between the two manuals above which is odd, does anyone out there know why?


November 1969-

There is reference to the Baird badged 720 series (Thorn 2000 series chassis) in some of my Radio Rentals technical bulletins. By this time the RCA inspired 700/710 series chassis had been dropped in favour of the Thorn 2000. Likely short lived.


Early 1970

The Thorn 3000 MKI is adopted on the likes of the 721, 722 & 724. The "M" prefix dropped as they which were all now prefixed with an "8" to denote a Radios Rentals badged Thorn  chassis, like the 8724.

Hereafter Radio Rentals use the 3000 MKII, 3500, 8000 and so on for their Baird badged sets.

Sorry to have waffled on.

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Posted : 11/12/2017 8:29 pm
colourmaster, slidertogrid, Nuvistor and 6 people reacted
Captain Peacock
(@captain-peacock)
Posts: 21
Eminent Member Registered
 

Crusty,

Having worked for RR in the 1970s, I can confirm the Baird 720 series used the BRC 2000 chassis and were not at all popular with either subscribers or engineers.

But as you say, the 'later' 721,722 & 724 models had an '8' prefix and used the BRC 3000 chassis. The model descriptions (from memory) are as follows:

8721 19 inch table model with 19" CRT (A49-192X?) with rounded corners in a dark imitation rosewood cabinet and fitted with a 4-button mechanical UHF tuner.

8722 ditto but 22 inch CRT (A55-14X)

8724 full length 25 inch CRT (A63-11X) console model with sliding tambour doors in dark cabinet with plastic gold/brass coloured CRT surround and fitted with a 4-button mechanical UHF tuner.

I am currently in the process of compiling as complete a list as possible of all the Baird model numbers I and an ex-colleague and long time friend of mine can remember or ever worked on. I will post it when it is as complete as we can make it.

Regards,

CP

 
Posted : 08/12/2023 1:02 pm
Nuvistor reacted
Jayceebee
(@jayceebee)
Posts: 2004
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@captain-peacock Hi Ex D.E.R. here so may be able to help fill in some blanks after the 8757. Before this model was introduced we had very different styling, after it was just slight cosmetic tweaks apart from a couple of 9900 series models. @Crustytv is very keen to find an 8102 with it's slot in remote.

Have you seen his epic 8724 blog?

John.

 
Posted : 08/12/2023 3:11 pm
Captain Peacock
(@captain-peacock)
Posts: 21
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Much thanks John and yes, I have seen Crusty's 8724 restoration project and was gobsmacked to see that a 3500 chassis would work with the 'rounded' (A55-14X/A63-200X) CRTs as the 3500 was introduced with the FST tubes (A56/A66/67-120X) and had a pincushion correction system added via a transductor (which used to burn up) on the larger convergence PCB.

As for Baird/TTR model numbers, this is what I have so far - all from memory, so any help would be appreciated and many thanks for it in anticipation.

 

8763: 20 inch CRT with 6-button varicap tuner & Nixie tube channel number display. (8800 chassis)?

8764: 22 inch version of 8763 (8800 chassis)?

8766: As 8764 with additional simple two-tone ultrasonic remote control (sound mute & channel increment) fitted with a Ducati varicap tuner which had very weak AFC (8800 chassis)?

8767: As 8766 but with an improved varicap tuner unit which had stronger AFC (8800 chassis)? This tuner assembly could be retro-fitted in the 8766.

8769: 26 inch FST full IR remote control handset with Teletext decoder(?) in a light full length cabinet (8800 chassis)

8770: 20 inch FST PIL CRT in dark cabinet with simple ultrasonic remote control (9000 chassis)

8773: Same as 8763 but with different cabinet (8800 chassis)? (same as Multi-broadcast 5773)

8774: Same as 8773 but 22 inch CRT in a different cabinet (8800 chassis)?

8776: 22 inch FST PIL CRT 9600 chassis (with simple remote control) (9600 chassis)

8778: As 8773 but with touch channel selector unit (that kept getting stuck on one channel!) (8800 chassis)?

8779: 22 inch version of 8778 (8800 chassis)?

8785: 26 inch table/consolette with full IR remote.

8787: 14 inch ‘portable’ colour set in a white plastic cabinet with a solid-state Nordmende chassis.

I recall attending many simple (ultrasonic) remote control sets of this era with remote control/random channel change faults that were down to the (usually intermittent)  failure of numerous tantalum caps on the R/C PCB. These caps also caused many other faults in these sets as well.

I also seem to remember that with the introduction of the TX9 chassis, the Baird model numbering system changed to a 81xx number e.g. 8102 for the 20 inch full IR control TX9 chassis that was housed in the bottom of the TV front. I don’t remember any models after that as I left in October 1980 so I never encountered the TX10 chassis or what I think was the swansong of the 8000 chassis derivatives – the 9800.

There was also a full-height console 26-inch Prestel TV which I think used either a 8800 or 9600 chassis fitted with a Viewdata/Prestel (and Teletext?) decoder. I only ever saw one of these.

8101 20 inch PIL tube with simple ultrasonic remote control (sound mute & channel increment (TX9 chassis)

8102 20 inch PIL tube plain cabinet with full IR remote (TX9 chassis)

8132 22 inch PIL tube in full length cabinet with single sliding door & full IR remote (TX9 chassis)

8142 26" Full length cabinet with sliding door & full IR remote (TX9 chassis)

8170 14” ‘Portable’ (TX9 chassis?)

Again, any help would be gratefully appreciated.

 
Posted : 09/12/2023 10:41 am
Jayceebee reacted
Jayceebee
(@jayceebee)
Posts: 2004
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@captain-peacock I don't recognise the x763/4/6 models, perhaps they were unique to RR and I wasn't aware of them. The 8101 and 8102 I'm sure were 9900 series but we had our own more conventional styling, the 5111 and 5112. Other models which were common to both outlets I can think of were the x729 a 22" consollette with sliding tambour door but using the oddball A55-14X rounded corner CRT, same set with A56-120X was the x734, also a table model x744. These latter two models were rented in huge numbers during the colour boom years. You forgot to mention the unique RR model 8750 made by Korting, there was also another Nordmenede model the 8180 which had latching tuner buttons. Did RR take any 4000 chassis models? we had two 26" sets, 5762 and 3C05. I remember Prestel sets branded RRC, Radio Rental Contracts, one used the very luxurious x769 cabinet but with 9600 chassis and another which was similar but not quite the same as the first Teletext model with Texas XM11 decoder, x782. 

BTW the first digit of the model number was 5 for D.E.R.

John.

 
Posted : 09/12/2023 8:55 pm
Captain Peacock
(@captain-peacock)
Posts: 21
Eminent Member Registered
 

Ah yes, sorry about omitting the 8750: how could I forget that model, it was my favourite set (well from a picture quality aspect anyway). That set appeared to be a variant of the Korting Transmare 51763. Not sure if this faulty design was used in all the hybrid Transmare range, but there was a serious design flaw in that the CRT heaters had one end 'earthed' to chassis which created many CRT failures with heater-cathode shorts - particularly in the Sylvania CRTs originally fitted. We had to do a mod which removed the 'earth' connection from the heaters and lifted both sides of the heaters to around 100V DC as per the Thorn 3000 chassis via R603/4 potential divider. This mod killed the heater-cathode short problem stone dead.

Just don't mention the 8752: that 26 inch 110 degree CRT set was a NIGHTMARE with its solid-state thyristor line output stage. Thankfully, I only ever went to one - that was enough!

I don't think RR ever bought in any BRC4000 chassis sets: well, none that I saw anyway. They did, howver, buy in an awful lot of the 8000/8500 and its descendants. However that chassis ever drove a 26 inch CRT (8769 fitted with 8800 chassis) is beyond me: the tube looked flat from new!

Oh, and anyone remember those AWFUL red tantalum caps that intermittently failed with monotonous regularity - particularly on the ultrasonic remote receiver PCBs? We nicknamed them 'tantrum tantalums.' One engineer at our branch came up with the following er, 'joke': "what's the connection between tantalum caps and Robin Hood?" to which he then sang... "tantalum, tantalum, tantalum, tum, tum" to the tune of Robin Hood! Yes, our workshop was a proper loony bin!

I had also forgotten about the 8180!

Thanks JCB for your help - list suitably amended.

If anyone has any knowledge of the various Baird model numbers for the 420, 440 and 460 mono chassis series I'd be very grateful. I realise this is a big ask as these sets were released around 70 years ago!

CP

 
Posted : 12/12/2023 12:11 pm
colourmaster reacted
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