K2 Option Bypass Headers

K2 Option Bypass Headers

K2 Option Bypass Headers

K2 Option Bypass Headers

The descriptions below assume an understanding of the Elecraft® K2.
If you are unfamiliar with the K2, you may find it helpful to first visit
the K2 Internal Option Basics and Understanding Un-Modules pages.

Our K2 Op­tion By­pass Head­ers kit pro­vides a com­plete set of un-modules for the Elecraft® K2.  These devices are ideal for trou­ble­shoot­ing and tin­ker­ing since they sim­pli­fy the task of re­con­fig­ur­ing the K2 to en­a­ble op­er­a­tion up­on re­mov­al of their as­so­ci­at­ed op­tion.  But more im­por­tant­ly, they al­so make it pos­si­ble to build a new K2 that’s Option Ready from the out­set; when used in con­junc­tion with our re­work-free K2 as­sem­bly method.

Latest News

4 June 2012 – The last of the re­quired com­po­nents to pack­age the kits are due to ar­rive to­day.  To­mor­row Ken will be­gin proc­ess­ing and ship­ping or­ders in the se­quence they were sub­mit­ted.

29 May 2012 – The PCBs have left man­u­fac­tur­ing and gone to ship­ping more than a week ahead of sched­ule!  If they don’t ac­tu­al­ly ship to­day, they’ll most cer­tain­ly go out by to­mor­row.

9 May 2012 – PCB pro­duc­tion is un­der­way.  Kit­ting should oc­cur in mid-June, cul­mi­nat­ing with de­liv­er­ies in late-June.

What Others Have Said

Off-Re­flec­tor (di­rect email) com­ments …

F5VJC “… ex­cel­lent …
… pro­fes­sion­al …
… use­ful …”
VE3HLS “… paid for them­selves …”
NIØC “… an ex­cel­lent prod­uct.”
WØAG “… ex­cel­lent cus­tom­er ser­vice …”
WØGAV “… very fine boards!
 … very nice work.”
WØYK “… ex­cep­tion­al …”
NE1RD “… bril­liant!”
W1MU “… gen­ius …”
K3UJ “… amaz­ing …”
KI4NVX “… im­pressed …”
W4DAS “… very im­pressed …”
KD5EJA “… handy …”
KE6US “… very handy …”
KJ7RT I’m a be­liev­er.”

Com­ments in the Elecraft® Re­flec­tor ar­chives and eHam Re­views …


Additional comments.

Do I really need your K2 Option Bypass Headers to use your method?

Even with­out our op­tion by­pass head­ers, you can still in­stall P6 (Aux RF) and P3 (Aux 12V) on the RF board, and the nine KSB2 sup­plied front panel parts dur­ing the in­itial build.  By do­ing this, the sub­se­quent in­stal­la­tion of the KSB2 and ei­ther the KAT2 or KPA100 (top-cov­er) options won’t re­quire the sig­nif­i­cant dis­as­sem­bly of the en­clo­sure that would oth­er­wise be nec­es­sary.

Oth­er than that, in the ab­sence of our op­tion by­pass head­ers we sug­gest that you fol­low Ele­craft’s tra­di­tion­al as­sem­bly in­struc­tions.  That said, we feel we need to di­rect­ly ad­dress the fact that some “ex­pe­ri­enced” build­ers have men­tioned us­ing jump­er wires and ca­pac­i­tors in place of most of our head­ers.  Be­yond be­ing more te­di­ous to in­stall, there are two “Re­li­a­bil­i­ty” re­lat­ed rea­sons why we dis­cour­age the use of these ad hoc de­vices:  1) the pos­si­bil­i­ty of gal­van­ic (dis­sim­i­lar met­al) cor­ro­sion on the in­ter­nal con­tacts of the K2’s gold-plat­ed con­nect­ors; and 2) the pos­si­bil­i­ty of dam­age re­sult­ing from mis­tak­en­ly in­sert­ing a jump­er wire in the wrong place, and then trans­mit­ting.  In the ab­sence of our Head­ers kit, we be­lieve the li­a­bil­i­ties re­sult­ing from these is­sues, off­set the benefits of our as­sem­bly method.  Es­pe­cial­ly for long-term use, and es­pe­cial­ly for build­ers who are new to elec­tron­ics and/or who might have dif­fi­cul­ty fab­ri­cat­ing and prop­er­ly us­ing these de­vices.

Re­gard­ing the “com­par­a­tive­ly” elab­o­rate 150 Ohm, 5 dB at­ten­u­ator cir­cuit on the Noise Blank­er un-module … over the years at least two K2 own­ers have men­tioned on the Re­flec­tor, that “tem­po­rar­i­ly” they just used a jump­er wire in­stead!  Al­though in hind­sight, a 90 Ohm re­sis­tor might have been a bet­ter choice?  Ei­ther way, this type of “NB By­pass” hack is not ap­pro­pri­ate for per­ma­nent or ex­tend­ed use.

Buy Now

The internal mic adaptor kit is currently out of production, pending sufficient interest for a possible next production run.

Parts List
  • 1.3" × 3.825" cir­cuit board which snaps apart yield­ing six ti­ny head­ers
  • 230 mil con­tact, break-away SIP ter­mi­nal strip with 10 µ" gold plat­ed con­tacts:  60 pins (40 + 20)
  • 318 mil con­tact, break-away SIP ter­mi­nal strip with 10 µ" gold plat­ed con­tacts:  11 pins (8 + 3)
  • Resistors (¼ W 5%):  100 Ω; 470 Ω; 560 Ω
  • Caps:  .001 µF monolithic; 4.7 (or 5) pF NPO
  • Hardware:  4-40 × ¼" Phillips machine screw; #4 split lock washer
  • Quick Start Instruction Sheet (QSIS)
  • Foam Home” – 2" × 4.5" × ½" an­ti-stat­ic closed-cell rig­id pink-poly foam (for stor­ing head­ers when not in use)
Current App Notes
4.7 pf Cap Installation
Headers Kit: 4.7 pF Cap

3 May 2012 – The pho­tos of the as­sem­bled Head­ers kit – both on our web­site and in our PDF in­struc­tions – show the 4.7 pF cap on the UN-K60XV head­er “stand­ing” up­right.  In con­trast, the 3 May 2012 ver­sion of the Head­ers kit Quick Start In­struc­tion Sheet (QSIS) sug­gests that this cap should be in­stalled tilt­ed more than 45 de­grees from ver­ti­cal.  Please fol­low the in­struc­tions in the QSIS when in­stall­ing this cap and po­si­tion it tilt­ed suf­fi­cient­ly that it ex­tends no high­er off the board than the height of the in­su­lat­ing body of P15.


Even stand­ing ver­ti­cal­ly, the cap will still eas­i­ly clear near­by K2 com­po­nents when the UN-K60XV head­er is in­stall.  The only con­cern is that the cap could be dam­aged when the UN-K60XV head­er is not in­stalled in your K2, but is in­stead parked/stored on the “Foam Home” that’s in­clud­ed with the kit.

Corrective Action

If you’ve not yet as­sem­bled your head­ers kit, just fol­low the in­struc­tions in the lat­est QSIS.  If you al­ready built the kit, do not at­tempt to tilt the cap once it has been sol­dered in place, since do­ing so could dam­age/crack the me­nis­cus on its leads.  In­stead, make a suit­a­ble in­den­ta­tion/hole in the foam im­me­di­ate­ly be­low where the cap will re­side.  Then just be sure to al­ways po­si­tion the UN-K60XV board on the foam, such that the cap is di­rect­ly over this lo­ca­tion.  (You might find it help­ful to draw an out­line of the board in this po­si­tion, with a per­ma­nent mark­er.)

Download (Headers Kit) Documentation
schematic diagram
headers installed
rev G PCB & assembled kit
rev G PCB photo-realistic rendering
rev G PCB x-ray rendering

From left to right:  Headers Installed; PCB Scan + Assembled Kit; 1,000 DPI Photo-Realistic Rendering; 2,000 DPI X-Ray Rendering.
These are thumbnails, click to enlarge.

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