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Television Standards Converters, Modulators etc Standards converters, modulators anything else for providing signals to vintage televisions.

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Old 10th Feb 2006, 5:16 pm   #21
Nickthedentist
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Default Re: 405 easy converter kit - does it make sense?

Quote:
Originally Posted by Darius
I have a pic of the down side of the MK II board, maybe it helps.
That looks very densely wired, Darius, now I can see why it's smaller than if you used a single-sided PCB.

I notice you've used board with pads rather than strips. What wire do you use for the interconnections, enamelled copper (like you'd use for coils and transformers) or something a bit more special?

Nick.
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Old 10th Feb 2006, 5:27 pm   #22
oldeurope
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Default Re: 405 easy converter kit - does it make sense?

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Originally Posted by Nickthedentist
That looks very densely wired, Darius, now I can see why it's smaller than if you used a single-sided PCB.

I notice you've used board with pads rather than strips. What wire do you use for the interconnections, enamelled copper (like you'd use for coils and transformers) or something a bit more special?

Nick.
Hi Nick,
yes, I use transformer wire. The soilderable kind of course and plastic
spray to fix it.

Kind regards
Darius
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Old 10th Feb 2006, 5:54 pm   #23
ppppenguin
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Default Re: 405 easy converter kit - does it make sense?

For many years (before surface mount made it impossible) I used plain pinboard for prototyping. Just like veroboard but with no copper at all. I mount most components on pins and wired with a mixture of tinned copper and fine insulated wire. The wire I usually used was actually designed for wire wrapping. Sometimes I used a sort of pen with a reel of fine enamelled wire. I forget the name of this system. I often used to put a good solid 0V wire all the way round the edge of the board. This was very useful in video designs. Occasionally I used "colander ground plane" boards. These are like the one Darius shows but with a ground plane on the other side. This is mostly covered with solder resist which is easily scraped away to make a good 0V connection. These boards approximated a PCB with continuous ground plane. Very good for video and high frequency work.

In previous pictures I have also seen Darius use plain pieces of copper clad board. The circuit is assembled in mid air or holes can be drilled and counterbored to give isolated connections. This is an excellent high frequency technique.

I don't like veroboard with copper strips.

Whatever you use for prototyping, a PCB is really the only solution for a kit that may be built by relatively inexperienced people. The simplest PCBs, with just one copper layer, are fine for simple circuits. Double sided, ideally with plated through holes, would be ideal for Darius's converter but this costs a lot more than single sided and is difficult to etch at home. The Aurora converter uses a 4 layer PCB and is designed and built exactly as a professional design. One of the layers is a continuous ground plane. Small boards like this are not too expensive provided you order a fair quantity (25+, preferably 100+) and are not fussy about delivery time. I think Darryl paid something like $20 for each Aurora PCB.

Enough of my ramblings. It's Darius's design and entirely his choice of PCB etc.
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Old 10th Feb 2006, 6:38 pm   #24
evingar
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Default Re: 405 easy converter kit - does it make sense?

Quote:
I don't like veroboard with copper strips.
Neither do I, aside from the strips giving too many capacitive effects on high frequency circuits, you have to spend ages hacking loads of copper away to get anything approaching the component density Darius is showing. Also, with vero strip, it is all too easy to leave mega thin copper shorts where you thought you had cleared the strip cleanly. I use round or square pad as Darius has done. Square or round pad also makes mounting PTH PLCC sockets on patch board a lot easier.

WRT Darius's design, it looks a good alternative to the more expensive standards converters available, but I would echo previous comments. IMHO to get a reasonable take-up amongst those whose primary interest is in vintage video, a PCB would have to be provided. Ideally a full kit of parts should also be provided, but failing that it is vital to provide any components that are difficult to source. IMHO people simply will not buy a kit if there is even a smidgeon of a chance that some parts will be unattainable. Just by two pennorth. Well do
ne Darius for making the effort – I really hope this project will be a success
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Old 10th Feb 2006, 6:57 pm   #25
oldeurope
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Default Re: 405 easy converter kit - does it make sense?

Quote:
Originally Posted by ppppenguin

...I don't like veroboard with copper strips.

Whatever you use for prototyping, a PCB is really the only solution for a kit that may be built by relatively inexperienced people. The simplest PCBs, with just one copper layer, are fine for simple circuits. Double sided, ideally with plated through holes, would be ideal for Darius's converter but this costs a lot more than single sided and is difficult to etch at home. The Aurora converter uses a 4 layer PCB and is designed and built exactly as a professional design. One of the layers is a continuous ground plane. Small boards like this are not too expensive provided you order a fair quantity (25+, preferably 100+) and are not fussy about delivery time. I think Darryl paid something like $20 for each Aurora PCB.

Enough of my ramblings. It's Darius's design and entirely his choice of PCB etc.
Good evening Jeffrey,
yes I agree. I don't like vero board with copper strips too.
I think this depends in what you started with.
This is definately nothing for a kit.
I don't want to etch at home. The problem with multilayer is, if somebody
destroies a hole there is no contact to the inner layers any more.
I want to make it with one layer. This makes it easy to follow a wire with
your eys to find mistakes.
If you repair something without a layout (and schematic) it is much better
to have only one layer. With two layers it is very difficult and multilayer
no chance.
My soft is able to generate a so called "ground polygon".
Means it fills every space with ground. I used this with great success at
the UVB.

Kind regards
Darius
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