K2 D36

[KBG Luxford]

Hi Everyone,
I have restarted work on my K2 S/N 3068 after experiencing trouble
aligning the VCO.  So I downloaded a fresh copy of the manual and have
checked off the parts on the RF board up to Alignment and Test Part II.
  Now I am puzzled.  The new manual mentions D36, a 5082-3081 diode, yet
on the board, soldered there a couple of years ago (hence my memory is
not clear) looks to be a 1N400x.  I have searched the Builder Alerts,
yet there is no mention of D36.  Has there been a change to the
specification of D36?

Many thanks
Kevin
VK3DAP / ZL2DAP
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[Don Wilhelm-4]

Kevin,

When the Keying Waveshape Mod was incorporated into the K2, the type of
diode used at D36 changed.  If you add the keying waveshape kit, you
will find the new diode in that package, but if you are not adding the
keying waveshape change at this time, the 1N4007 should be used.

Since you are just now building your K2, I suggest you order the PLL
Thermistor mod and the Keying Waveshape mod (you will need firmware
2.04p and IOC 1.09 to apply the keying waveshape change, so check your
firmware chips).  With those 2 kits and a pair of 1N4148 diodes to use
at D40 and D41 (Extremely Strong Signal Handling mod), you can build
your K2 up to the current ship level - in fact, you can even build it
from the new manual, but you will have to do the cut on the control
board for the Keying Waveshape change.

Caution, if you do work from the newest manual, there are a few part
number changes because of the hassle introduced when the K2 became RoHS
compliant.  Actually better to work from your older manual and the
upgrade kit instructions.  There is no kit for the D40 and D41
additions, see the newer manual to determine where to add them.

73,
Don W3FPR

KBG Luxford wrote:

> Hi Everyone,
> I have restarted work on my K2 S/N 3068 after experiencing trouble
> aligning the VCO.  So I downloaded a fresh copy of the manual and have
> checked off the parts on the RF board up to Alignment and Test Part
> II.  Now I am puzzled.  The new manual mentions D36, a 5082-3081
> diode, yet on the board, soldered there a couple of years ago (hence
> my memory is not clear) looks to be a 1N400x.  I have searched the
> Builder Alerts, yet there is no mention of D36.  Has there been a
> change to the specification of D36?
>
> Many thanks
> Kevin
> VK3DAP / ZL2DAP
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
> http://mailman.qth.net/mailman/listinfo/elecraft   
> Help: http://mailman.qth.net/subscribers.htm
> Elecraft web page: http://www.elecraft.com
>
>

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[KBG Luxford]

Hi Don,
Good advice in almost real time!
Thanks for putting me right on D36 and the waveshape mod.

I am having a lot of trouble with T5 and aligning the VCO.  This is the
subject of a number of emails to and from Gary Surrency.  Awful things
have happened like pads lifting from the board when removing T5 to
change the number of turns!  But I won't go into that year.  Suffice to
say I got discouraged for a couple of years, but have revived my
determination to fix this radio and get it going.  In parallel I am
working on an early S/N K2 that someone else gave up on, and I have got
that VCO aligned OK - so all is not yet lost.

Incidentally, I have added D40 and D41.

Thanks again
Kevin
VK3DAP / ZL2DAP

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