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K2: winding T5

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lstavenhagen

K2: winding T5

Hi all,

I'm at the point of winding T5 and have a question about whether I have it wound correctly. In particular, it seems like the step-down winding (the 4 turns of green wire) can't be perfectly centered over the other winding (the 16 turns of red wire). I.e. if you start counting turns on the 16-turn coil from one side, the first pass through the core of the 4-turn winding occurs between winding 6 and 7. If you start counting turns from the other side, the first pass of the 4-turn winding occurs between windings 7 and 8.

Does this sound like it's wound right? I can't see any other way to wind the xformer without this being the case. It's symmetrical if I turn it over - i.e. if I flip it, the 4-turn winding is "off" to the other side by 1.

if this is wound right, does it matter which way it's installed? i.e. which leads are 1/2 and 3/4?

The manual doesn't specify so I'm assuming it doesn't. But this is a little bit of a Rubik's cube type of puzzle for me I guess ;)

Thanks,
LS

Don Wilhelm-4

Re: K2: winding T5

LS,

You have it wound correctly. The orientation is indicated on the next
page of the manual - Figure 6-16 shows the lead numbering, and it is
critical.

73,
Don W3FPR

lstavenhagen wrote:

> Hi all,
>
> I'm at the point of winding T5 and have a question about whether I have it
> wound correctly. In particular, it seems like the step-down winding (the 4
> turns of green wire) can't be perfectly centered over the other winding (the
> 16 turns of red wire). I.e. if you start counting turns on the 16-turn coil
> from one side, the first pass through the core of the 4-turn winding occurs
> between winding 6 and 7. If you start counting turns from the other side,
> the first pass of the 4-turn winding occurs between windings 7 and 8.
>
> Does this sound like it's wound right? I can't see any other way to wind the
> xformer without this being the case. It's symmetrical if I turn it over -
> i.e. if I flip it, the 4-turn winding is "off" to the other side by 1.
>
> if this is wound right, does it matter which way it's installed? i.e. which
> leads are 1/2 and 3/4?
>
> The manual doesn't specify so I'm assuming it doesn't. But this is a little
> bit of a Rubik's cube type of puzzle for me I guess ;)
>
> Thanks,
> LS
>
>

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lstavenhagen

Re: K2: winding T5

Hi Don,

Ok, thanks.
So which way should it go in? I.e. should leads 1 and 3 be where the last winding of the 4-turn (lead 3) be the side where it's between turns 6 and 7 of the 16 turn coil or the side where it's between 7 and 8 (and the inverse for leads 2 and 4)? It's different depending on how I have the xformer flipped. Also, why isn't this specified?
Looks like most of the rest of the transformers have this situation and I don't see the orientation specified for those either.

Thanks,
LS

Don Wilhelm-4

Re: K2: winding T5

LS,

I don't understand your confusion - the lead numbers are clearly
silkscreened on the board, just match them up.
If the silkscreen on your board is sub-standard, refer to the parts
placement diagram at the back of the manual or the board images
available at Tom Hammond's website www.n0ss.net.

For 'beauty', orient it with the yellow side up.

73,
Don W3FPR

lstavenhagen wrote:

> Hi Don,
>
> Ok, thanks.
> So which way should it go in? I.e. should leads 1 and 3 be where the last
> winding of the 4-turn (lead 3) be the side where it's between turns 6 and 7
> of the 16 turn coil or the side where it's between 7 and 8 (and the inverse
> for leads 2 and 4)? It's different depending on how I have the xformer
> flipped. Also, why isn't this specified?
> Looks like most of the rest of the transformers have this situation and I
> don't see the orientation specified for those either.
>
> Thanks,
> LS
>
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lstavenhagen

Re: K2: winding T5

Hi Don,
I'm talking about how the small winding isn't exactly centered within the big winding, it's offset towards one end of the big winding by one turn. I'm only wondering if it matters which end of the big winding it should be offset to (i.e. the lead 1 end or lead 2 end) - it differs if you flip the xformer over.

But it sounds like that part doesn't matter, as long as I follow the rest of the diagram which is clear. I'll solder 'er in after the superbowl ;)

Thanks Don,
LS

Don Wilhelm-4

Re: K2: winding T5

LS,

Yes, it does not matter if it is not exactly centered - close is good
enough. The toroid core provides the coupling required.

73,
Don W3FPR

lstavenhagen wrote:

> Hi Don,
> I'm talking about how the small winding isn't exactly centered within the
> big winding, it's offset towards one end of the big winding by one turn. I'm
> only wondering if it matters which end of the big winding it should be
> offset to (i.e. the lead 1 end or lead 2 end) - it differs if you flip the
> xformer over.
>
> But it sounds like that part doesn't matter, as long as I follow the rest of
> the diagram which is clear. I'll solder 'er in after the superbowl ;)
>
> Thanks Don,
> LS
>
>

lstavenhagen

Re: K2: winding T5

Ok, thanks Don.

I feel kind of guilty because seems like I should have a bunch more questions. But I'm just not having that much trouble so far. even grounding the crystal cans went pretty smoothly hi hi once I read all the suggestions on how to do it (tin the cans first! Then hold the ground leads in place by putting a spare anti-static pad leftover from the IC's under the board and sticking them into it through the grounding holes).

As for tinning the toroid leads, I did find that the solder blob method was ineffective. Perhaps a 700F tip just doesn't get hot enough to melt the insulation? Instead, I'm sanding the leads first with a bit of sandpaper to get the stuff mostly off then tinning. This gives a very nice tin on the wires and good solder connection on the board.....

Is this meant to be done with an 800F or hotter tip?

Thanks es 73,
LS

Vic K2VCO

Re: K2: winding T5

On 2/8/2010 8:31 AM, lstavenhagen wrote:

> As for tinning the toroid leads, I did find that the solder blob method was
> ineffective. Perhaps a 700F tip just doesn't get hot enough to melt the
> insulation? Instead, I'm sanding the leads first with a bit of sandpaper to
> get the stuff mostly off then tinning. This gives a very nice tin on the
> wires and good solder connection on the board.....
>
> Is this meant to be done with an 800F or hotter tip?

I do it with a 700F tip. It seems to help to start at the cut end of the wire where the
copper is exposed. Hold the iron against it until the blob begins to bubble, then move it
up toward the core. Add solder as needed.
--
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco
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Matt Palmer-4

Re: K2: winding T5

In reply to this post by lstavenhagen

The solder blob method takes a little trick, you have to sit on the
end of the wire long enough for the insulation to melt (heat has to
transfer to the wire). I usually just scrape with a xacto these days
and then tin, I think it is cleaner and easier than solder blob. When
I built my K2 I used a lighter to burn the insulation and sandpaper to
clean it up. It is just as effective.
Matt
W8ESE

On Mon, Feb 8, 2010 at 11:31 AM, lstavenhagen <[hidden email]> wrote:

>
> Ok, thanks Don.
>
> I feel kind of guilty because seems like I should have a bunch more
> questions. But I'm just not having that much trouble so far. even grounding
> the crystal cans went pretty smoothly hi hi once I read all the suggestions
> on how to do it (tin the cans first! Then hold the ground leads in place by
> putting a spare anti-static pad leftover from the IC's under the board and
> sticking them into it through the grounding holes).
>
> As for tinning the toroid leads, I did find that the solder blob method was
> ineffective. Perhaps a 700F tip just doesn't get hot enough to melt the
> insulation? Instead, I'm sanding the leads first with a bit of sandpaper to
> get the stuff mostly off then tinning. This gives a very nice tin on the
> wires and good solder connection on the board.....
>
> Is this meant to be done with an 800F or hotter tip?
>
> Thanks es 73,
> LS
> --
> View this message in context: http://n2.nabble.com/K2-winding-T5-tp4531587p4535190.html
> Sent from the [K2] mailing list archive at Nabble.com.
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>
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>

lstavenhagen

Re: K2: winding T5

Yeah, that was what I was doing, I sat and sat and sat on the wire and the insulation just wouldn't cook off... Oh well, the sanding method is working tho so I'll just use that for the rest of the coils. This part is slower going for sure since I'm double and triple checking the winds.

I am noticing that with the suggested wire lengths I'm ending up with 3 and 4" of wire leftover after the wind. I sure hope I'm not going to run out of wire right at the end.... I'm assuming there's extra wire in the supplies?

LS