[Elecraft] KPA100 parts issues

[Don Wilhelm]

Tom,

You point out some of the fallacies in attempts to identify components. 
  As far as the inductors are concerned, the only thing that matters is 
the color code stripes.  The fact that they had tan bodies when the 
manual was written has been superseded by either a change in vendor or 
the whim of the manufacturer.  I believe the current bodies may be 
green.  Even if the body color is yellow, white, tan, green, blue or any 
other color, if the stripes are brown, black, brown, that would indicate 
a 100 uH inductor.

Capacitors are similar, but can be more complex.  The significant 
identifiers are the value and the rated voltage.  In the case of the 
1200 pf capacitors, that value would be indicated by '122' which means 
two significant digits of '12' followed by 2 zeros - so 122 equals 1200 
pf.  the other marking of '630' should indicate the voltage rating. 
While capacitors may vary a lot in the particular markings that may be 
used, it is always a good idea to become familiar with the marking 
conventions that are in current practice.  The Component Data section of 
the ARRL Handbook has a good writeup on capacitor markings that every 
builder/ham should be familiar with.

Now, the 4N7 marking - the 'N' indicates 'nanofarad', which is likely 
fully understood by European hams, but not so certain by US hams who are 
more accustomed the microfarads and picofarads.  Nanofarads is 10^-9 and 
  therefore 1 NF is 1000 pf or .001 uF.  An easy way to convert is to 
slide the decimal point (represented on the capacitor by the position of 
the 'N') by 3 places.  So a capacitor marked 4N7 is 4.7 Nanofarads, or 
4700 pF, or .0047 uF.

OK, so much for the tutorial - all your assumptions are correct.

73,
Don W3FPR

KJ3D wrote:
> Good Evening,
> 
> Before contacting Elecraft, perhaps someone is currently building a KPA100
> or has recent experience who could answer some questions.
> 
> I have completed the parts inventory for the KPA100 and have a three
> unresolved issues.
> 
> 1.  Inventory says RFC3 and 11 have tan bodys.  I have two of the same value
> only with green bodies.  Is this OK?
> 
> 2.  Inventory says C64 and C79:  .0047 (472) .4 LS mono 250 V or above.  I
> have 2 squarish blue things identified as 4N7 J250 TD with .4 LS.  I cannot
> identify them as being anything else.  Ya think they're C64 and C79?
> 
> 3.  Errata says C2A and C6D:  1200 pf (6122) 630 Poly.  I have a pair of
> brown caps labeled P122J 630 F that I cannot associate with anything else.
> Again, are these C2A and C6D?
> 
> Thanks,
> 
> Tom, kj3d at comcast.net