27th Feb 2021, 1:52 pm | #201 |
Hexode
Join Date: Sep 2019
Location: Crystal Palace, Bromley, London, UK.
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Re: My first telly TV22
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27th Feb 2021, 6:13 pm | #202 |
Pentode
Join Date: Jan 2021
Location: York, North Yorkshire, UK
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Re: My first telly TV22
Your use of an Arduino for the wire feed guide could mean it also has the potential to work as a wave winder as well.
I was wondering about that - in principle I see no reason why not - its just an electronic cam function - in my day job I do a lot with multi axis servo systems and robots and this is a standard function - should be possible to implement with steppers - probably using Gcode would be the easiest way. I read somewhere that the wire is impossible to get hold of if you were to try to rewind the overwind for example - but what is special about it? |
28th Feb 2021, 8:11 pm | #203 |
Pentode
Join Date: Jan 2021
Location: York, North Yorkshire, UK
Posts: 155
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Re: My first telly TV22
So I cobbled together my coil unwinding machine and dissected the LOPT windings.
I am in the process of uploading a video to youtube and will share it once that is done. As far as I could tell there may have been two places where the primary and secondary were connected - one at the end of the last layer of the primary , the paper seems very crumbly at the ends of the winding, but also there was another fault somewhere in the middle of the last layer. Overall a straightforward operation - lets see how putting it all back on again works out!!. |
28th Feb 2021, 8:53 pm | #204 |
Pentode
Join Date: Jan 2021
Location: York, North Yorkshire, UK
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Re: My first telly TV22
Here is link to video. Will try to get rewind done some time next week work permitting.
https://www.youtube.com/watch?v=SKLh...ature=youtu.be |
28th Feb 2021, 9:40 pm | #205 | |
Hexode
Join Date: Sep 2019
Location: Crystal Palace, Bromley, London, UK.
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Re: My first telly TV22
Quote:
What was your turn count in the end? Helder |
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28th Feb 2021, 9:47 pm | #206 |
Pentode
Join Date: Jan 2021
Location: York, North Yorkshire, UK
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Re: My first telly TV22
Pretty much as posted by Andy(Beery) give or take a turn.
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28th Feb 2021, 10:07 pm | #207 |
Pentode
Join Date: Jan 2021
Location: York, North Yorkshire, UK
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Re: My first telly TV22
Here is the final score
The paper used between layers measured at 0.11mm thick , so the magneto tape I have is thinner than this |
28th Feb 2021, 10:13 pm | #208 | |
Hexode
Join Date: Sep 2019
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Re: My first telly TV22
Quote:
Helder |
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28th Feb 2021, 11:12 pm | #209 |
Heptode
Join Date: Jun 2006
Location: Ware, Hertfordshire, UK.
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Re: My first telly TV22
I agree,
it must be thinner than that. When measuring such small things as paper insulation or even wire diameter, I always use a micrometer, which is much more accurate than a caliper. Good to know my turns count wasn't far off. Cheers Andy
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1st Mar 2021, 3:34 pm | #210 | |
Hexode
Join Date: Sep 2019
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Re: My first telly TV22
Quote:
I never fully disassembled my lopt. Prior to varnishing, I simply squeezed the laminations together and machined a small restraining piece to keep them together (see photo below). Helder |
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1st Mar 2021, 7:16 pm | #211 |
Pentode
Join Date: Jan 2021
Location: York, North Yorkshire, UK
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Re: My first telly TV22
Hi Helder
I think there may have been two faults , one at the end of the final layer and one in the center of the final layer. My impression is that the white spirit hadn’t reached into the center of the windings. The winding when originally done seems to have had molten wax brushed on ( I’m guessing) so my impression is of an homogenous mixture of wire/paper/wax and no smell of white spirit. I’m pretty sure that white spirit/varnish would help with reinforcing the insulation at the ends of the windings which is probably where most faults would occur. As for the thickness , I am probably measuring wax and paper , the paper/wax has the impression of the wire embossed into it , so the actual paper may well be thinner |
1st Mar 2021, 9:29 pm | #212 |
Dekatron
Join Date: Jan 2004
Location: Newcastle upon Tyne, Tyne & Wear, UK.
Posts: 8,194
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Re: My first telly TV22
Hi Folks, a piece of heavy duty heatshrink tube works wonders in keeping the lams together
Ed |
1st Mar 2021, 10:06 pm | #213 | |
Hexode
Join Date: Sep 2019
Location: Crystal Palace, Bromley, London, UK.
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Re: My first telly TV22
Quote:
Thanks. Wax & paper are definitely not a good combination (think capacitors). Based on your results, I think it is unlikely that any varnish has made it to the central portion of the windings in my lopt, so I agree with you that the protection is mostly at the ends. On the other hand, the white spirit and varnish (given enough immersion time) should be able to infiltrate into the very same areas where humidity (and air) tend to go to, and hence where reinforcement is more important and necessary. I don't know how long my varnished lopt will last, but Argus25's TV22 lopt was "turped & varnished" many years ago (10+?) and is still going strong, whereas my first lopt (left original and untreated) lasted for a few hours prior to developing the dreaded short. Helder |
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1st Mar 2021, 10:14 pm | #214 |
Hexode
Join Date: Sep 2019
Location: Crystal Palace, Bromley, London, UK.
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Re: My first telly TV22
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2nd Mar 2021, 12:21 pm | #215 |
Pentode
Join Date: Jan 2021
Location: York, North Yorkshire, UK
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Re: My first telly TV22
I guess in due course I will discover if dismantling this thing was a good idea or not. But it’s an interesting learning curve and if I get stuck hopefully I can send it to Ed to be properly done!
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2nd Mar 2021, 12:31 pm | #216 |
Pentode
Join Date: Jan 2021
Location: York, North Yorkshire, UK
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Re: My first telly TV22
I suppose a halfway house would be to remove the inner windings and immerse those in a very much thinned down varnish , even better under vacuum. That way you would not make it very difficult to remove again later if a fault did occur.
The transformer varnish I used ( from RS components) seems to dry to an almost caramel consistency to is quite easy to crumble off if needed. Not sure standard varnish would be as easy to remove for reworking if needed. |
2nd Mar 2021, 4:50 pm | #217 | |
Hexode
Join Date: Sep 2019
Location: Crystal Palace, Bromley, London, UK.
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Re: My first telly TV22
Quote:
Helder |
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2nd Mar 2021, 5:43 pm | #218 |
Octode
Join Date: Jan 2009
Location: Falmouth, Cornwall, UK.
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Re: My first telly TV22
Peak voltage across the capacitor is 830 volts
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Stephen _________"It`s only an old telly" ___ |
2nd Mar 2021, 6:56 pm | #219 |
Pentode
Join Date: Jan 2021
Location: York, North Yorkshire, UK
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Re: My first telly TV22
Ok thanks for the info
Lams are in vinegar deejaying SHMBO not impressed at consumption of good wine vinegar |
2nd Mar 2021, 6:56 pm | #220 |
Pentode
Join Date: Jan 2021
Location: York, North Yorkshire, UK
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Re: My first telly TV22
Derusting i mean
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