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Forum 141

[Closed] Recreating the GEC 8161 Mirror Lid TV

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Brian Cuff
(@briancuff)
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Hi all.
As many of you know, I purchased the empty GEC 8161 TV on ebay. There are no known examples of this set and so this cabinet is very important. I am going to attempt to re-create the innards as closely as possible to the originals but unfortunately, there seems to be a dearth of info on this set or on its smaller cousin, the 9122. I have been trawling through my RX data for a likely candidate for the radio chassis. GEC seemed to have gone mainly for rotary pointers and dials and the (poor) pictures of the 8161 we have indicate a linear dial. Looking at the knob positions and scale size, I think that the radio could be a modified "GEC Fidelity SW5". Does anyone have one of these and even better, does anyone have one of these which they are willing to part with as a possible donor? As soon as I get the cabinet, I will clean it up a little and post some pictures. The vendor lives in Sudbury but I find that there are two Sudburys! One near Ipswitch :( and the other near London :D . I am waiting to hear which - I bet it's the Suffolk one!!!
This is going to be a loooooonnnnng drawn out thread I imagine and any advice is welcome.

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Posted : 30/09/2012 9:06 pm
crustytv
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Posted : 30/09/2012 9:14 pm
Anonymous
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Very exciting Brian, good luck!

The brochure is a good start. I wonder if Ericsson might hold the GEC archives as I think they are the current successor of the company. Failing that, Marconi before them. I bet there's a wadge of design documents sat waiting on a shelf for you somewhere :) .

Keith

 
Posted : 30/09/2012 9:26 pm
Till Eulenspiegel
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Hi Brian,
Thank goodness it's you who has won the cabinet. I should be in the shop this week so I will take some pictures of the chassis of the BT9121.

Till Eulenspiegel.

 
Posted : 30/09/2012 9:33 pm
Brian Cuff
(@briancuff)
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Thanks guys. When I get the cabinet, I'll see if I can make some sense of the fittings that are left. Hopefully, the chassis mounts will be either threaded bushes or some sort of counter-bored holes which took rubber washers rather like the HMV 800 chassis mounts. I will also look for witness marks where the brackets were. This cabinet was rescued from an Attic. The builders rescued the cabinet because they recognizable it as a piece of furniture. I wonder if they skipped the chassis because they were not recognizable as anything.

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Posted : 30/09/2012 9:39 pm
IJK2008
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Hi Brian

Glad to hear the cabinet is in good hands.

It make take a while but I bet you get there.

Ian

 
Posted : 30/09/2012 9:57 pm
Katie Bush
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Thank you Lord for prayers answered...!

I'm glad it came to someone with the skill and desire to recreate the original innards.. I was having nightmares about that cabinet ending up as a wine cabinet or a "retro" (you know, the more I hear that word, the more I hate it) housing for some hideous LCD TV, or worse still, some nasty amplifier with an MP3 player stuck on the end of it :mrgreen:

Somewhere, I have a GEC table top radio, and a GEC radiogram, of approximately WW2 period, but I haven't seen either in years, and I doubt if they'd be what you're looking for.. It's a pity you don't have any pictures or sketches of the radio chassis.

Marion

 
Posted : 30/09/2012 10:19 pm
Anonymous
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:thumbl: A vote of Moral support across the Irish sea. Nothing else I'm likely to be able to do.

 
Posted : 30/09/2012 10:31 pm
Till Eulenspiegel
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Two pictures of the still not restored chassis of my BT9121.
Note the compact timebase unit.

Till Eulenspiegel.

 
Posted : 30/09/2012 10:56 pm
Brian Cuff
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Hi Till
Do you have the schematic for the 9121? The 8161 had 22 valves including the radio chassis. I counted 19 on your chassis which leaves only 3 for the radio chassis. That could be FC, IF and 1st audio but would mean strange switching for the power supply for radio only! These combined radio/TVs normally have 2 mains transformers to simplify this but the 9121 wouldn't show this which probably means that the chassis are not too similar. The layout of controls on your TB chassis also look too complicated for the 8161 with 7 controls whereas from the brochure pictures, it looks as though the 8161 has only three but there seems to be a little sub-panel which could hold the "minor" controls. This is going to be real detective work!

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Posted : 30/09/2012 11:55 pm
Till Eulenspiegel
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Hi Brian,
I have a good deal of BT9121 info. I'll send you copies.
Another complete BT8161 does exist and I know the guy who owns it. I'll look back to my old emails in 2003/4 and try to contact him. He was very helpful when I was doing the cabinet reconstruction of the BT9121.

Till Eulenspiegel.

 
Posted : 01/10/2012 12:05 am
Brian Cuff
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Wow! That's good news, Till. Let's hope that he can help us.
Presumably you have pictures of the innards of the 6122 which you did the cabinet for - I would like to see those as well if you have them.

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Posted : 01/10/2012 12:30 am
Till Eulenspiegel
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Hi Brian,
I've just sent an email off to the 8161 owner. Let's hope I receive a reply. He could be using a different email adress now.

Till Eulenspiegel.

 
Posted : 01/10/2012 12:42 am
Anonymous
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Another complete BT8161 does exist and I know the guy who owns it.

Let's hope and pray that it's not the same set.

Keith

 
Posted : 01/10/2012 9:24 am
Till Eulenspiegel
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Hi Keith,
I think that the other set is the 10 X 8 picture model BT8121, uses the 12 " CRT.
The CRT in the BT8161 must have a 15 inch diameter, even larger than the tube used in the Cossor 137T.

Till Eulenspiegel.

 
Posted : 01/10/2012 12:18 pm
Brian Cuff
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Yes Till, the 8161 uses a 15" tube giving a picture of 13.5" x 12". The 9122 uses a 12" tube with a picture size of 10" x 8". The height of the 8161 is 6.25" greater than the 9122 which shows how much longer the 15" tube is.
I got confused between the 9121 which you are restoring and the 9122 which is the mirror lid set so the pictures I asked for won't be that useful - sorry about that!

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Posted : 01/10/2012 12:56 pm
Anonymous
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I've just been checking through my magazines, brochures etc. Some pictures of the upright 1936 GEC models but nothing else that would help you Brian, I'm afraid.

Keith

 
Posted : 01/10/2012 1:26 pm
Brian Cuff
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Thanks for looking Keith.

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Posted : 01/10/2012 1:33 pm
Till Eulenspiegel
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Circuit diagrams of the GEC BT8161 and the GEC BT912. Although the two chassis are similar there a few noteworthy differences. Both are superhets operating with low IFs. In the TV only receiver 9121 the RF amplifiers and frequency changer are on the vision chassis section. In the more higher specced up 8161 it would appear that the television early stages are actually on the "A" chassis, the radio receiver section. We'll have to do more research to confirm that.
The vision demodulator in the 8161 is of the full wave type, which is desirable because of the very low intermediate frequency and the large 15" CRT. The much cheaper BT9121 has a simple half wave vision demodulator.
So it would seem that the main differences are in the signal circuits. The timebases and vision power supply arrangements are similar between the two chassis.

Till Eulenspiegel.

 
Posted : 02/10/2012 1:10 am
Duke Nukem
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What's the record for the highest number of windings on a single mains transformer ? The GEC sure looks like a good candidate !

BTW, shouldn't the 8161 have a 16" tube not 15" ?

TTFN,
Jon

 
Posted : 02/10/2012 9:09 am
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