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Vintage Television and Video Vintage television and video equipment, programmes, VCRs etc. |
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22nd Aug 2011, 12:05 pm | #1 |
Dekatron
Join Date: Mar 2005
Location: Gateshead, Tyne and Wear, UK.
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Bush TV12 restoration.
Let's see if I can get this set working before the weekend.
The results so far are a narrow thin horizontal line and an indicated 4KV EHT. DFWB. |
22nd Aug 2011, 12:08 pm | #2 |
Hexode
Join Date: Feb 2011
Location: Gloucestershire, UK.
Posts: 376
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Re: Bush TV12 restoration.
I'll race you .. I've got a TV22 just arrived. Not powered it up yet , but I'm hoping the LOPTx is OK, so the line whistle will drive away the woodworm in the side panels
Last edited by Andy Doz; 22nd Aug 2011 at 12:13 pm. |
22nd Aug 2011, 12:52 pm | #3 |
Dekatron
Join Date: Mar 2005
Location: Gateshead, Tyne and Wear, UK.
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Re: Bush TV12 restoration.
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22nd Aug 2011, 3:49 pm | #4 |
Dekatron
Join Date: Jul 2008
Location: Charmouth, Dorset, UK.
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Re: Bush TV12 restoration.
I would turn the brightness down on that!
Peter |
22nd Aug 2011, 3:58 pm | #5 |
Dekatron
Join Date: Mar 2005
Location: Gateshead, Tyne and Wear, UK.
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Re: Bush TV12 restoration.
Following my policy of Glasnost (openess) I can report that the line timebase has packed in.
DFWB. |
22nd Aug 2011, 4:27 pm | #6 |
Dekatron
Join Date: Jun 2005
Location: Warnham, West Sussex. 10 miles south of DORKING.
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Re: Bush TV12 restoration.
No excuses allowed! As soon a a challenge rears it's head you creep back into the workshop! I'm backing you David. Don't allow the TV22 brigade to intimidate you. .
The EHT on a TV12 is rarely above 4.9kv unless it is fitted with the later line output transformer. It still gives a good picture even with this very low EHT potential. Boost cap and coupling caps come to mind. It was a good first light. Pity the bulb in the lighthouse popped just before you crashed into the rocks. Even with that minimum display it shows a good CRT and LOPT, the rest is easy. Regards, John. |
22nd Aug 2011, 4:44 pm | #7 |
Dekatron
Join Date: Sep 2006
Location: Kilmarnock, Ayrshire, UK.
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Re: Bush TV12 restoration.
Has war broken out in the vintage community?
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22nd Aug 2011, 4:58 pm | #8 |
Dekatron
Join Date: Mar 2005
Location: Gateshead, Tyne and Wear, UK.
Posts: 7,444
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Re: Bush TV12 restoration.
Hi Trevor,
Not exactly war, let's say a difference of opinion. Eine Meinungsverschiedenheit TV12 versas TV22, no competition. Everyone knows which is the better set. DFWB. |
23rd Aug 2011, 8:04 am | #9 |
Hexode
Join Date: Feb 2011
Location: Gloucestershire, UK.
Posts: 376
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Re: Bush TV12 restoration.
... it's just I happened to have a TV22 to do at the same time ...
I can confirm my line stage doesn't work either, the top cap's fallen off my line bottle.. |
23rd Aug 2011, 8:16 pm | #10 |
Hexode
Join Date: Feb 2011
Location: Gloucestershire, UK.
Posts: 376
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Re: Bush TV12 restoration.
A few caps. Repair the top cap on the line output valve ... and up with the volts!!
... there's all to play for. |
23rd Aug 2011, 9:45 pm | #11 |
Heptode
Join Date: Apr 2003
Location: Rugby, Warwickshire, UK.
Posts: 816
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Re: Bush TV12 restoration.
Nice to see the tube 'smiling'!
You know you're well on your way at that stage! Greg
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Greg BVWS committee chairman |
23rd Aug 2011, 10:34 pm | #12 |
Dekatron
Join Date: Mar 2005
Location: Gateshead, Tyne and Wear, UK.
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Re: Bush TV12 restoration.
I've been working on the TV12 today. The line oscillator failure turned out be be a broken tag on the EF50 valveholder. An easy fix. So it's back to the original line TB fault, lack of width. The 'scope shows that the sawtooth drive is correct: 30volts @ 100microseconds. Note the "sit up" on the flyback part of the waveform. The frame timbase needs some attention.
That's the next stage of the restoration. DFWB |
23rd Aug 2011, 10:37 pm | #13 |
Dekatron
Join Date: Mar 2005
Location: Gateshead, Tyne and Wear, UK.
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Re: Bush TV12 restoration.
Some pictures. The broken valveholder tag can been seen.
DFWB. |
23rd Aug 2011, 10:52 pm | #14 |
Dekatron
Join Date: Mar 2005
Location: Gateshead, Tyne and Wear, UK.
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Re: Bush TV12 restoration.
The frame timebase turned out to be the same valveholder problem. Two broken tags. The FTB now works in a fashion but the hold control has a dead spot at one end. It's a 2.2Megohms lin pot.
The frame timebase employs a Miller Transitron circuit. The line time oscillator is a more conventional blocking transformer circuit. Plenty height now but just look at the width. DFWB. |
24th Aug 2011, 8:17 am | #15 |
Hexode
Join Date: Feb 2011
Location: Gloucestershire, UK.
Posts: 376
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Re: Bush TV12 restoration.
I think you're inchining into the lead now ....
Does someone have a TV22MKI schematic or trader sheet I can borrow? |
24th Aug 2011, 8:25 am | #16 |
Moderator
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Location: Exeter, Devon and Poole, Dorset UK.
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Re: Bush TV12 restoration.
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Invisible airwaves crackle with life or at least they used to Mike T BVWS member. www.cossor.co.uk |
24th Aug 2011, 10:16 am | #18 |
Dekatron
Join Date: Aug 2007
Location: W.Butterwick, near Doncaster UK.
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Re: Bush TV12 restoration.
Think your Frame Osc Tx could be o/c Andy.
David |
24th Aug 2011, 10:17 am | #19 |
Dekatron
Join Date: Aug 2007
Location: W.Butterwick, near Doncaster UK.
Posts: 8,923
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Re: Bush TV12 restoration.
Think i have MK1 sheet can scan and send.
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24th Aug 2011, 10:24 am | #20 |
Dekatron
Join Date: Aug 2007
Location: W.Butterwick, near Doncaster UK.
Posts: 8,923
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Re: Bush TV12 restoration.
Just send me a PM with email address and its sat here on my desktop ready to go!
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