Rework-Free K2 Assembly

Rework-Free K2 Assembly

Rework-Free K2 Assembly

Rework-Free K2 Assembly


Add­ing most options to a stock K2 first re­quires modifying the ra­dio’s circuitry At least this is true if it was built per the tra­di­tion­al meth­od sug­gest­ed in the K2 as­sem­bly man­u­al.  A re­work-free “Op­tion Ready” K2 on the oth­er hand, is one for which all such mod­i­fi­ca­tions were seam­less­ly in­cor­po­rat­ed dur­ing its in­itial con­struc­tion.  We re­fer to this ap­proach to build­ing a K2, as “our al­ter­nate as­sem­bly meth­od”.

Our meth­od makes use of op­tion by­pass head­ers – A.K.A. un-modules plus the fol­low­ing ad­di­tion­al parts, to ful­ly pop­u­late a stock K2’s three main cir­cuit boards …

(9) caps; (2) di­odes; (2) re­sis­tors; (1) re­sis­tor net­work; (1) tran­sis­tor; (4) 1x3 sock­et; (1) 1x5 sock­et; (2) 1x8 sock­et; (1) 1x12 sock­et; (1) 1x16 sock­et; (1) 2x8 ter­mi­nal strip; (2) 2-pin plugs; and (4) stand­offs.

These parts are not pro­vid­ed with the base K2, but in­stead are in­clud­ed with their as­so­ci­at­ed op­tion.  This “pack­ag­ing ap­proach” con­trib­utes to the ra­dio’s bar­gain in­tro­duc­to­ry price, how­ev­er the trade­off is that in most cas­es, in­stall­ing these parts – af­ter com­plet­ing the in­itial build – is a considerable un­der­tak­ing.

Be­yond the ad­di­tion of these parts, sev­er­al “orig­i­nal” com­po­nents (three caps + three re­sis­tors) and hand­ful of jump­er wires must be re­moved from the K2’s main cir­cuit boards.  Of con­cern is the fact that in some cas­es, the parts that need to be add­ed need to be in­stalled in lo­ca­tions va­cat­ed by orig­i­nal K2 parts that were re­moved. 

Fur­ther, in three cas­es the new­ly add­ed parts are SIP mat­ing con­nect­ors for which pre­cise align­ment and me­chan­i­cal­ly sound sol­der con­nec­tions are es­sen­tial.  There­fore the re­moved parts must be ta­ken out with con­sid­er­a­ble care, and pref­er­a­bly with spe­cial­ized de­sol­der­ing equip­ment.  This type of rework can af­fect a print­ed cir­cuit board’s re­li­a­bil­i­ty, so it fol­lows that our meth­od could sig­nif­i­cant­ly im­prove the re­li­a­bil­i­ty of your ra­dio.

close-up of UN-KNB2 header installed

The ben­e­fits of our as­sem­bly meth­od be­come ev­i­dent the mo­ment you be­gin en­hanc­ing your K2 with options Es­pe­cial­ly when add­ing any of the six that plug di­rect­ly on­to the K2’s main cir­cuit boards.  What would oth­er­wise have been a significant chore, in­stead amounts to un­plug­ging tiny bypass headers That’s it!  No dis­as­sem­bly, PCB re­work, or sol­der­ing are nec­es­sary!

Latest News

5 June 2012 – Com­pan­ion Guide III (CG3) has been pub­lished.  This man­u­al pro­vides the in­struc­tions for im­ple­ment­ing our as­sem­bly meth­od.  Spe­cif­i­cal­ly, use CG3 with Ele­craft’s rev H or rev I K2 man­u­als.  There is no cus­tom­ar­y “tem­po­rar­y be­ta re­lease wa­ter­mark” be­cause the dif­fer­enc­es (ver­sus CG2) are triv­i­al.

What Others Have Said

Here are some re­lat­ed com­ments in the Elecraft® Re­flec­tor ar­chives and eHam Re­views …

VE3WMB “… the doc­u­men­ta­tion was ex­cel­lent!”
AC0DS “… I’m glad I used this ap­proach.”
N1AS “… well worth it and went smooth as silk.”
W1SRB “… a breeze …”
N4FSC I am very glad that I did …”
N6KR “… by all means, con­sid­er this meth­od.”
AD7GR I am very glad that I did.”
AL7B “… very sim­ple …”
N8LP It’s a great idea.”
W8GX “… you will ap­pre­ci­ate how much work this elim­i­nates.”

Additional comments.

Frequently Asked Questions
Download (Assembly Method) Documentation
close-up of UN-KNB2 header installed


This pro­ce­dure has been in use since the re­lease of our orig­i­nal (rev D) Headers kit in the sum­mer of 2005; al­though back then our in­struc­tions were lit­tle more than a list of de­vi­a­tions from the steps in the K2 man­u­al.


Op­tion­al mod­ules (options) can be add­ed to an “Op­tion Ready” K2, with­out the need for ex­ten­sive dis­as­sem­bly of the en­clo­sure or any ad­di­tion­al sol­der­ing on the ra­dio’s three main cir­cuit boards.  How­ev­er …

  • Before in­stall­ing some op­tions you must first:
    • Install one or two op­tion-sup­plied con­nect­ors on the rear I/O pan­el (K160RX and K60XV re­spec­tive­ly).
    • Replace a ma­chine screw (se­cur­ing the Con­trol board) with the op­tion pro­vid­ed hex spac­er/stand­off (KAF2 or KDSP2).
  • After in­stall­ing some op­tions you must then:
    • Realign the 80/160 me­ter band­pass fil­ter (K160RX).
    • Check the VCO range on 60 me­ters, and if nec­es­sary re­a­lign the VCO (K60XV).
    • Per­form crys­tal fil­ter setup and BFO optimization pro­ce­dures (KSB2).  It may al­so be nec­es­sary to re-jump­er the mic con­fig­u­ra­tion head­er be­hind the front pan­el.  This step can be avoid­ed if the head­er is pre-con­fig­ured for your mi­cro­phone dur­ing as­sem­bly.  That is, un­less you lat­er de­cide to use a mi­cro­phone with a dif­fer­ent con­nect­or pin-out, or one re­quir­ing a dif­fer­ent bi­as re­sis­tance.  The best way to avoid pos­si­bly hav­ing to dis­as­sem­ble the front sec­tion of your K2 to ac­com­mo­date a dif­fer­ent mi­cro­phone, is to al­so in­stall our In­ter­nal Mic Adap­tor (IMA) dur­ing the in­itial build.

Companion Guides

These guides pres­ent our al­ter­nate as­sem­bly meth­od in the form of an­no­tat­ed K2 man­u­al pag­es.  The an­no­ta­tions are col­or-cod­ed, mak­ing it easy for ad­vanced build­ers to omit “Op­tion Ready” sup­port on a case-by-case ba­sis.  A sec­ond­ary ben­e­fit of the col­or-cod­ing is that it makes the in­struc­tions eas­i­er to fol­low.  (Note!  The same col­or-cod­ing scheme is used on the What Else Do I Need? page.)


This meth­od is not an ap­proved Elecraft® mod.  Fur­ther, Ele­craft’s kind per­mis­sion to re­pro­duce por­tions of the K2 man­u­al does not con­sti­tute an en­dorse­ment of our prod­ucts.  Our meth­od may not be ap­pro­pri­ate for eve­ry­one, par­tic­u­lar­ly build­ers who …

  • just feel more com­fort­a­ble ex­act­ly fol­low­ing the man­u­fac­tur­er’s as­sem­bly in­struc­tions.
  • want to build the base ra­dio for the ab­so­lute min­i­mum (in­itial) cost.
  • do not plan to add any in­ter­nal op­tions.
  • find our in­struc­tions too con­fus­ing or too much ad­di­tion­al work .
  • have the nec­es­sary skills and equip­ment to per­form the PCB rework that’s oth­er­wise nec­es­sary to add some op­tions.
  • do not mind sig­nif­i­cant­ly dis­as­sem­bling the en­clo­sure as re­quired to add most op­tions.
  • are not con­cerned about the re­sale val­ue of their ra­dio.
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Updated 1329 UTC Thursday 8 MAY 2014
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