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Vintage Television and Video Vintage television and video equipment, programmes, VCRs etc.

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Old 15th May 2020, 7:55 pm   #141
deepspacedaz
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Default Re: Fixing a GEC BT 302 Television

I grew up in the 80s. - 90s I just need some help putting these valves back correctly Ive posted a picture
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Old 15th May 2020, 8:33 pm   #142
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Default Re: Fixing a GEC BT 302 Television

Hi Daz, many moons ago Steve Colourstar kindly made me a couple of videotapes of 405 line material. I could lend you one by post when you think it's time to offer up a signal, so if you can rustle up 2 video's you can make a copy. I can also lend you the vhf modulator you will need. to connect from your video to the telly. The standards converters are great, but expensive ! I made one once but the picture was full of noise ! Regards John
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Old 15th May 2020, 8:35 pm   #143
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Default Re: Fixing a GEC BT 330 Television

Thanks a lot yeah sounds great.

For now I just need help with these valves please
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Old 15th May 2020, 9:11 pm   #144
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Default Re: Fixing a GEC BT 302 Television

Does anyone know?
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Old 16th May 2020, 5:37 am   #145
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Default Re: Fixing a GEC BT 302 Television

If you do an internet search for “Frank Cuffe hedgehog” you should find a relatively low cost answer to your problem.

Valve pinouts....rectifier B9A base 1..IC,2..ic,3..k,4..h,5..h,6..ic,7..ic,8..ic,9..a
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Old 16th May 2020, 10:00 am   #146
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Default Re: Fixing a GEC BT 302 Television

Some very generous and kind offers there Daz.

If you follow exactly the advice suggested I'm sure you will get a result. Make sure you know how to use your meter and understand the volts both AC and DC and resistance readings as these are important and false information given will lead to many posts and frustration to all concerned.
You do not need to use the current ranges of your meter or rather the amps and m/a until you are completely familiar with it. You can damage the meter if improperly connected to voltage on the current ranges.

Just to prove it can be done I pulled a GEC BT302 out of the loft yesterday afternoon. Externally it looked good but the inside was absolutely filthy but was mostly original and complete. It was in a much worse state than yours but after replacement of a couple of valves and a basic capacitor overhaul, it works! it's all a matter of procedure.
The chassis has had an incredible amount of use. It's previous owner probably turned it on at 8am for the test card music and turned it off at 10.30pm after the Queen at closedown as we used to say.

Ok the test card is not perfect but it works! All I can say is good luck with it. Stick with it and don't divert to other projects as it becomes very confusing to follow. Take it easy. John.
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Old 16th May 2020, 10:36 am   #147
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Default Re: Fixing a GEC BT 302 Television

Thanks for the information about the standards converter link. I just need help with the valves. I was told to take them out yesterday and someone said they would help me put them back in, I was up to 4 am trying to figure this one out.
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Old 16th May 2020, 12:05 pm   #148
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Default Re: Fixing a GEC BT 302 Television

These two pictures show the printed circuit boards removed from the working BT302 mentioned earlier.

Starting with the I.F. Panel.Valves V4-V5-V6 and V7 are all Z329 valves. These are equivalent to the Mazda 30F5. The valve pictures that you posted earlier show a couple of odd valves namely the Marconi version of the EF80, the Z152 and another type that looks like another EF80 probably a Mullard.

These last two are not direct equivalents of the Z329 series but WILL WORK in place of the Z329 your chassis. The Z329 is easily recognized by it's dark gray perforated screen that can be seen inside the valve.

V8 is a DH77 that may be labeled 6AT6 or EBC90. V9 is a N369 or it's equivalent the Mazda 30P12. It's taller than the others as can be seen by the picture.

That concludes the I.F. panel.

Next the tuner. It is VITAL that you get these in the correct order. If they are reversed smoke will issue from the tuner so take care.

Looking in from the back of the chassis the valve nearest you is a LZ329. This is equivalent to the Mullard PCF80 or the Mazda 30C1. The valve in front, nearest the tuner control knobs is a B319 equivalent to the Mullard PCC84 or Mazda 30L1. This is the reverse of most tuners so take care. If in doubt about these ask!

The timebase panel.

V12. Large octal. N308. This may be a 30P4 Mazda or a PL36 Mullard It has a top cap. V13. U339. This may be a Mazda U191 and maybe shorter than the N308. Also has a top cap. V14 and V18 are both Z329. V17 is a D77 or Mullard EB91. It can be confused with the DH77 in the IF panel as it looks similar. If unsure post a picture. V16 B729 or Mazda 6/30L2. Short valve of similar size to tuner valves. DO NOT MIX THESE UP!

The last valve is a N379 or a Mazda 30P18, Mullard PL84. It looks almost identical to the N369 in the I.F. panel. It is the same height and will interchange and work as it has the same base connections.
This is the best I can do at a distance. Hope it helps.
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Old 16th May 2020, 12:12 pm   #149
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Default Re: Fixing a GEC BT 302 Television

Thank you so much for this explanation I'll get to work
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Old 16th May 2020, 12:26 pm   #150
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Default Re: Fixing a GEC BT 302 Television

The DH77, I have a valve that says 6BX6. Is this the DH77
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Old 16th May 2020, 12:52 pm   #151
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Default Re: Fixing a GEC BT 302 Television

The 6BX6 is an equivalent of an EF80 - see John's comments re the IF panel.
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Old 16th May 2020, 1:00 pm   #152
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Default Re: Fixing a GEC BT 302 Television

Yes i just noticed thanks
I have another valve which is perforated inside Z152. Is this another version of Z329 ?
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Old 16th May 2020, 1:32 pm   #153
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Default Re: Fixing a GEC BT 302 Television

Same as your previous one - it's a EF80 direct equivalent.

Z152 EF80 6BX6 all equivalents.
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Old 16th May 2020, 1:32 pm   #154
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Default Re: Fixing a GEC BT 302 Television

This is it
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Old 16th May 2020, 1:38 pm   #155
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Default Re: Fixing a GEC BT 302 Television

This site will give you lots of information on valve types and equivalents.
http://www.r-type.org/index.htm
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Old 16th May 2020, 1:50 pm   #156
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Default Re: Fixing a GEC BT 302 Television

Thank you so confusing when there are different ones inside.
These are the 2 I have left.
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Old 16th May 2020, 2:03 pm   #157
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Default Re: Fixing a GEC BT 302 Television

Just take your time and double check everything. Keep referring back to John's instructions at #148 - excellent advice there.
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Old 16th May 2020, 3:14 pm   #158
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Default Re: Fixing a GEC BT 330 Television

Ok, I believe everything is ok. the small valve is at very bottom Timebase panel.

Shall I try to switch it on now ?
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Old 16th May 2020, 3:27 pm   #159
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Default Re: Fixing a GEC BT 302 Television

The short valve can be seen in the timebase panel picture. It has a B9A base, 9 pin. It is marked V16 B729. The one you have is a Mazda 6/30L2 which is a direct equivalent.

Double check all your work and if in any doubt, ask! Better that than a resistor burn up that we will never hear the end of. Good luck with it. Anything is possible. John.
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Old 16th May 2020, 4:12 pm   #160
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Default Re: Fixing a GEC BT 302 Television

Looks good then.
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