[Elecraft] Rev A to Rev B Upgrade

Fri Nov 15 10:09:00 2002

Don - that's a great and helpful list! Now I can gp through my manuals and see which ones I've already done while in the process of building. I haven't read all of the 18 gazillion messages about mods - so could you give me a quick one-liner as to why one would want to replace 14 crystals!!  Thanks and 73/Tim NZ7C

> 
> From: "Don Brown" <[email protected]>
> Date: 2002/11/15 Fri AM 09:39:05 EST
> To: "Elecraft" <[email protected]>
> Subject: [Elecraft] Rev A to Rev B Upgrade
> 
> Hi
> 
> I thought I would flesh out the list of mods required to bring a Rev A K2 to
> Rev B status. In case some of you were wondering what may need to be done on
> your K2
> 
> 
> 1  PLL - remove X2 and add R19 220 ohm
> 2  BFO - change out L33 with new toroid
> 3  D10 - replace with low drop diode
> 4  ALC - change R16 100K, R10 470 and add D8
> 5  10/12 meter - change value of C42 330 pf, 45 1 pf and 48 330 pf
> 6  RFC15 - add 100 uH choke to U4 supply line
> 7  RFC11 - change to 100 uH toroid choke 20 turns on FT37-43
> 8  add C28,29 - 12 pF across C21 and 23
> 9  change value C30,36 to 470 pF
> 10 add C224 - in series with P6 AUX RF .047 uF
> 11 change value C225 390 pf, 226 680 pF, 227 330 pF, L25 14 turns, L26 12
> turns
> 12 audio pot mod - several cut runs and jumpers on front panel, RF and
> control boards
> 13 sine wave side tone - add R11 47K and L1 82 mH
> 14 AGC threshold - add 50K pot at R1
> 15 voltmeter switch - remove and replace with jumper
> 16 added filtering on voltage sense - add cap at C17 .01 uF change value C42
> .1 uF
> 17 D19,20 and C71 for future 60 meter option - add varactor diodes and
> change value C71 82 pF
> 18 change R60 to fixed 100 ohm resistor
> 19 new crystals for CW and SSB - replace 14 crystals with more closely
> matched set
> 20 AUX BUSS filtering - change value R6 100 ohm, R64 100 ohm and C12 .0027
> uF
> 
> Don Brown
> KD5NDB
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