Nov 2nd What TV will you use?

[Mike Watterson]

Wasn't this start of official service, and previously they alternately did 220 and 405, with early sets having both settings?

Somewhat like there were Trade Tests on 625Line before BBC 2 service started, thought that, ITV in 1955 and FM Radio in 1955 were more definate so there were sets with FM or Band III in 1954.

[ppppenguin]

There were transmissions to Radiolympia in august 1936 on both standards. Then the official start of service on 2nd November. The 240 line service was abandoned in January 37 I think. Possibly February. Probably a few hundred sets in homes for start of service.

[Geordie McBoyne]

With regard to early Cossor televisions such as the 137T I believe no 240/405 switch was ever fitted.  The ritual of changing standards week by week was simply facilitated  by adjusting the line and frame hold controls.
Certainly there is no evidence of a standards switch on my set.

From the ETF:  http://www.earlytelevision.org/cossor_137.html

Also:     http://www.earlytelevision.org/dumont_180.html

The Dumont 180 was developed from the Cossor 137T.

Geordie McBoyne.

[Geordie McBoyne]

News Flash! Plugged the Cossor into the mains and in no time at all a bright raster appeared on the screen.

Geordie McBoyne.

[Murphyv310]

Hi.
Well as some may know I have had some personal problems over the last week or so. I actually thought that the whole exercise of bringing the Ekco into the house would have been shelved............... not so it seems. I'm getting a lift in with the set on Monday and a space will be cleared.
The set is heavy and fully assembled a definite two man lift, so I might remove the chassis for this to make it easier. The tube is not properly retained in this set until it is in the cabinet with the mask holding the tube in position, only the clamp round the gun holds it if the chassis is out. All scary stuff!!!!!

[Old Sparky]

I shall be watching the programme on a (fairly)modern Philips CRT TV, which is coming up for 15 years old, as it's the only fully working TV I own. Though this re-creation of the very first broadcast will be interesting for the subject matter, I've never been interested in repairing or restoring old TVs, and in fact, back in the early 70s, I scrapped a Bush TV53 I'd previously repaired, having replaced it with a more recent set capable of receiving BBC2, which is also long gone, and the make of which I've now forgotten.

[Geordie McBoyne]

Picture of the TV receiver unit, 1936 style.  HT is absent, move on to the power supply unit.

Geordie McBoyne.

[Geordie McBoyne]

Easy fix, the receiver HT supply rectifier had an OC filament.  The original Cossor valve was a type 4/100BU, the nearest Mullard equivalent is the FW4-500. Didn't have either of these in stock so an Osram U14 will be used as a temporary measure until the correct valve is found.
The set now displays a rather dim picture, what can anyone expect from an eighty year old CRT?  Note the compression at the left of the picture.  Frame and line holds are excellent, the picture remains locked over a wide range of rotation the hold controls.
Other details:  the horizontal picture shift has two controls.  The sound output valve is a Cossor type 2P, a two volt filament directly heated triode.   The TV receiver is a superhet, the IFs have not been determined yet.    Like the contemporary GEC TVs the Cossor also has a very low vision intermediate frequency and for that reason  a full wave video demodulator is employed, a Cossor DDL4 low capacitance double diode is used.

The set is far from perfect but it will ready for the 2nd of November.

Geordie McBoyne.  

[Mike Watterson]

I don't think the set my grandparents gave us in late 1950s was much better. We had to pull curtains and have light off to watch it. It was free standing with doors and two big knobs. We moved in 1960 and shortly before that had replacement watchable with daylight. Not long after we moved (late 1960 or maybe 1962) we had a rental set with a radio style tuning scale for UHF. I used to try it occasionally and thus "discovered" the start of test / trade transmissions from Divis. Certainly we had it a long time before there was any UHF. I stayed up late to watch the Moon landing on it. Shortly later we moved again and then rented a colour set.
I have three CRTs, a 14" Philips Colour, model and age unknown, bought S/H years ago for my son to use on his PS/2. He has flat LCD and newer consoles with HDMI, so gave it back. A 21" 4:3 Lidl branded Vestel that does 16:9. Both have Satellite receivers on SCART. The tuners are now redundant.
I have an older 2" ? JVC TV/Radio which however only works TV on VHF, the UHF does nothing, so I'd have to build a VHF modulator.
I can record with Satellite receiver cards on PC (it has two) and USB DTT. Also our living room Humax HD Freesat box records, though it's got a special Diseqc menu, so is more often used by wife to watch tennis on German Eurosport. I have a standalone DVD recorder too that can record video (the tuner is only analogue, so redundant).

BBC only LW, MW (night) and Satellite. I may watch on the 14" set but record and re-watch on the 40" HDTV later.

[Geordie McBoyne]

Later Saturday evening the Cossor TV developed a timebase fault. It's likely one of the triode CRT horizontal deflection plate drivers has failed.
The line timebase has two shift controls, under this fault condition only one works. I might be lucky and find one of the 5megohm stand off resistors has gone high value or OC.
The second attached picture shows the fault condition. The first picture shows the components associated with the CRT grid and cathode. Note the selenium rectifiers used for picture DC restoration and also the glass spark gaps.

DFWB.