[Elecraft] Notes to new K2 builders - Part 1

[Bill Tippett]

Hi Don and Gregg,

At 10:19 AM 3/12/04, Don Brown wrote:
>
>D3 is replaced with the 82k resistor as part of the key click mod now 
>included in all new K2's

         Aha!  Maybe Elecraft will revise the manual.

>2.  U1 is specified as NE602 or SA602 on page 19, but
>the IC in my kit was SA612...hopefully equivalent.
>
>Yes they are equivalent at HF frequencies

         I later saw that in the Appendix, but a revision on page 19
  might be in order.

>You should not work on a metal surface that is hard grounded. All ESD 
>protection should connect to ground through a high value resistor of 
>around 1 meg ohm or so. Having a grounded work bench is about the same as 
>standing in a bathtub of water. It could be dangerous if some equipment 
>failed and became electrically hot. The 1 meg resistor will protect you if 
>this happens. Wrist straps usually come with this resistor built in.

         Good point.  My wrist strap has the resistor but I'll
insert one between the cookie sheet and earth ground.

>I also do not like metal work surfaces because of the possibility of 
>shorts when working on disassembled equipment. If the pads you are using 
>are the black foam used for IC's then I would not use them for a work 
>surface because as they wear the foam disintegrates and little bits of the 
>conductive foam will get into places and cause shorts. If you want a soft 
>surface a clean shop towel or a cloth top mouse pad works well. You can 
>lightly mist the surface with anti static fabric spray or wipe the area 
>with a fresh drier sheet to improve the static resistance. The best 
>solution is a commercially made antistatic work pad with the ground wire 
>and the 1 meg resistor. These are about 1/8 inch thick foam with a tough 
>anti static vinyl top coating and are about 2x3 feet. The top is not 
>conductive enough to short out circuit boards placed on the mat but will 
>still dissipate a static charge. Unfortunately they are expensive, but you 
>may be able to find one on the surplus market or a used one with some life 
>left at a swap meet

         Radio Shack claims their Conductive Foam (P/N 276-2400)
"Does not particulate" but I'll watch for that.  They also have a
complete 24" X 26" mat and wrist strap for $24.99 (P/N 276-2370).

                                         73,  Bill  W4ZV