GEC BT5147 Revisited

That's a very impressive picture, how old is the set, 60 years or thereabouts?

Thanks Frank, yes it's over 60 by now assuming it was made in '53 or '54.

PYE625 said
Thanks Frank, yes it's over 60 by now assuming it was made in '53 or '54.  

5+1+47+(1900)= 1953.

Cathovisor said

5+1+47+(1900)= 1953.  

Someone has their thinking cap on this morning

The GEC BT5147 was the set that established the design philosophy for the following seven years of television production by the original company. In fact certain design features can be found in the 1962 model BT448 which was made after the manufacturing of GEC TVs was taken over by Radio and allied Industries. (Sobell)   A plinth type of Band 3 converter was made available for the BT5147. I seem to remember it was the BT304. These converters appeared for sale at knock down prices in the advertisement pages of the Practical Television magazine.

Till Eulenspiegel.      

And here is the advert for the plinth type converter, this advert was found in the April 1959 Practical Television.   The IFs are very close to the BREMA figures of 34.64 and 38.15Mc/s.   I bought one of these units in 1960 to convert my Pye FV1 12" TV set.  Like the GEC BT5147 the IFs in the FV1 are close to the later BREMA figures which became the norm from 1955 for almost all 405 line television receivers.  Only a few TV manufactures continued to use the older IFs of 16 and 19.5Mc/s, notably Masteradio. 

Till Eulenspiegel.

I wouldn't mind one of those plinths to go with my BT5147

Although I do have a BT1746 which is almost the same as a BT5147 but with built in band III....Note the 3 controls on the side as opposed to 2.

Marc.

GEC made their own 14" rectangular CRT, the type 7203A. Unlike the Mullard MW36-24 which has a tetrode gun assembly the GEC has a triode gun, similar to the Brimar C14BM.

Till Eulenspiegel. 

Till Eulenspiegel said
GEC made their own 14" rectangular CRT, the type 7203A. Unlike the Mullard MW36-24 which has a tetrode gun assembly the GEC has a triode gun, similar to the Brimar C14BM.

Till Eulenspiegel.   

Looks a better tube than the MW36-24 fitted in my set..... I'll phone 'em and place an order in the morning.

But think carefully before you buy one.  Fourteen pounds fifteen shillings was a lot of money in 1956 and is that purchase tax extra or included in the price?

Till Eulenspiegel.

Last weekend when the weather was really sunny I took a trip to Leek in Staffordshire with a pal of mine for a nose around the Saturday open-air antique market. I'd never visited before and was really quite taken with the place. Lots of nice old buildings, winding streets, covered arcades and also absolutely the best fish & chips I've had for a long while!

In one of the antique shops I spotted a GEC exactly like Andrew's on the sales counter. I was taken aback at how small they are.  Sadly this example was nothing but an empty case with a small fish tank placed inside. Down in the basement amongst the junk I found the chassis and then stumbled across the crt which had been necked. There were a couple of other tv chassis stuffed in a corner too, as well as a large round crt just sitting on a chair ready to be knocked about by the public (eek!) It seems that old sets that come in are routinely stripped out for sale as empty cabinets. There was a nice little early 50s HMV console which had suffered that treatment. Shame! Maybe next time I visit I should leave them my phone number to avoid any more sets being needlessly gutted.

Steve

After well over 18 months, I thought this set was due for another run. Dusted it down a little and connected up. I had set this to CH4, so the Aurora was altered from CH11 and away we go. Good old GEC reliability means it works fine after a warm up, with a good picture.

It is interesting to note that this set is DC coupled from the vision detector all the way to the CRT cathode, so no unpleasant black level variations with picture content. Although not as bright as CRT's in later sets, this has to be as near to photographic quality as I have seen. The definition is excellent with good geometry.

There was still loads of these sets still giving excellent service well into the 60s. I remember having to fix them. One problem solved was to replace the type 305 heater chain barrater  with a high wattage resistor fitted inside the ES lamp cap.

The N339 line output valve was on occasions difficult to find. The PL81 will work but has a short life. The French Mazda 21B6 was often used as a replacement for the N339.   https://www.radiomuseum.org/tubes/tube_21b6.html

Till Eulenspiegel.

This set uses a KT36 for the line output, being a larger bottle, it probably has a longer life. You can just see it in the second picture above, between the barretter and CRT neck.

I wish I had some better period material to view on the set, perhaps I'll find an Ealing comedy to watch, but I might get a DVD of the Coronation as that was from the similar time as this set.

Could you use this type of Freeview box to feed the Aurora, Talking Pictures TV have lots of old films to watch.

https://www.amazon.co.uk/Teknikal-HD-Freeview-Receiver-Switchover-Black/dp/B00RPVIH8O/ref=sr_1_3?ie=UTF8&qid=1543784352&sr=8-3&keywords=freeview+box+hdmi+output

Thanks Frank, at 20 quid, it certainly warrants a thought  ?