K2 Mic wiring problems

[Rolf Moberg, OH6KXL]

Uuh! This is going to be hard!

After completing ssb kit to K2 I decided to wire mics for K2. I have two
mic connectors, one for Heil headset adapter cable and another to be
used in Yaesu MH31 mic from FT857/817/897.

I decided to wire MH31 first. There was a RJ45 connector in cable.
Through the plastic you can see the colours and from the manual of ft897
you can check the proper wiring. I counted 8 colourful cables inside of
RJ45. (Two blacks!)

I cut RJ45 off and found a lot of cotton inside the mic cable. And lot
of bare, very thin copper wires. After cutting them off I counted the
cables. What? There are only seven colourful cables in the mic cable. I
think Yaesu has covered some bare copper wires with one extra black coating.

All the little cables are unusable. They are _very_ hard to strip. The
copper inside the coating is very very thin and it breaks all the time.
Almost half of the smaller cables are cotton! Cotton is twisted together
with three or four very thin copper wires.

After several tries I raised my hands. I gave up. I will not even think
about soldering those thin wires to mic connector.

After building a K2, installing hundreds of components, soldering
thousands of joints I couldn't install a microphone cable to mic
connector. Maybe you don't believe me. Try it!

I'll make home made Heil adapter (Kenwood version) tomorrow. It's going
to be a lot easier job.

Rolf Moberg
oh6kxl
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[Don Wilhelm-3]

Rolf,

Yes, it is going to be hard since you have already cut the cable.  It IS
possible to solder to those leads but it takes a great deal of care and
patience.  Do not try to trim off the cotton, just tin the leads as they are
(cotton and all) and it can work.  Headphone cords are similar construction,
so 'repairer beware'.  You might try soldering those thin wires to a short
intermediate wire rather than directly to the mic connector.  Good luck with
it, and I offer my sympathy!

I would advise anyone contemplating cutting one of those 'very flexible' mic
cords (particularly the coiled ones) to create an adapter rather than
cutting the cord - only becuase of the soldering problem.

For those who have a variety of mics, I strongly suggest creating an adapter
for each one and wire the K2 mic header straight across (Elecraft mic
wiring).

73,
Don W3FPR

> -----Original Message-----
>
> Uuh! This is going to be hard!
>
> After completing ssb kit to K2 I decided to wire mics for K2. I have two
> mic connectors, one for Heil headset adapter cable and another to be
> used in Yaesu MH31 mic from FT857/817/897.
>
> I decided to wire MH31 first. There was a RJ45 connector in cable.
> Through the plastic you can see the colours and from the manual of ft897
> you can check the proper wiring. I counted 8 colourful cables inside of
> RJ45. (Two blacks!)
>
> I cut RJ45 off and found a lot of cotton inside the mic cable. And lot
> of bare, very thin copper wires. After cutting them off I counted the
> cables. What? There are only seven colourful cables in the mic cable. I
> think Yaesu has covered some bare copper wires with one extra
> black coating.
>
> All the little cables are unusable. They are _very_ hard to strip. The
> copper inside the coating is very very thin and it breaks all the time.
> Almost half of the smaller cables are cotton! Cotton is twisted together
> with three or four very thin copper wires.
>
> After several tries I raised my hands. I gave up. I will not even think
> about soldering those thin wires to mic connector.
>
> After building a K2, installing hundreds of components, soldering
> thousands of joints I couldn't install a microphone cable to mic
> connector. Maybe you don't believe me. Try it!
>
> I'll make home made Heil adapter (Kenwood version) tomorrow. It's going
> to be a lot easier job.
>
> Rolf Moberg
> oh6kxl
>

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[Paul Bruneau]

On Jul 20, 2005, at 8:38 PM, W3FPR - Don Wilhelm wrote:

> I would advise anyone contemplating cutting one of those 'very
> flexible' mic
> cords (particularly the coiled ones) to create an adapter rather than
> cutting the cord - only becuase of the soldering problem.

Great advice, Don. They make the cables that way to prevent them from
breaking caused by flexing the cable during normal use. Phone cords are
the same way, on purpose (not because they are cheap or trying to cut
corners), and the tradeoff for being almost unworkable in a splicing
situation is that they last far far longer than a heavier gauge, more
"traditional" wire would.

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