[Elecraft] K1 Resistor Packs

[Brian Mury]

On Sun, 2006-03-12 at 18:57 -0800, Scott Lindstrom wrote:
> OK, I admit it, I wasn't paying attention and
> installed RP 1, 2 & 6 "backward".  I have no
> experience with resistor packs and don't know why a
> resistor would be polarized.

You're right, they're not polarized. 

There are two types of resistor packs. One has completely separate
resistors, with two pins for each resistor. The orientation of these
doesn't matter.

Some have only one pin for each resistor. The other side of all the
resistors are connected together, and are connected to a single common
pin, so the orientation does matter. Something like this (the X's
represent resistors):

___________
| | | | | |
| X X X X X
| X X X X X
| | | | | |

If you install the resistor pack backwards, the common lead is in the
wrong place.

If you prefer, here's a nice little graphic showing the two types of
resistor packs, which I found with Google Images:

http://www.owlnet.rice.edu/~elec201/Book/images/assembly/img10.gif

> So, the question is, is
> this a critical error? I've tried to solder-wick them
> out, but with through-plating, I'm thinking they'll
> have to come out in pieces.

You might want to try one of those spring-loaded solder suckers.
However, it's often better to destroy the component than to risk
damaging the board. A new board, plus all the components that are
already soldered to it, plus the time and effort you already put into
assembly, is worth a lot more than a resistor pack (which is quite cheap
anyway).

... or use it as an excuse to buy a vacuum desoldering tool such as the
Hakko 808... ;-)

http://www.hakko.com/english/products/hakko_808.html