[Elecraft] [K2] Forgetful K2 filters

Don Wilhelm w3fpr at embarqmail.com
Wed Apr 17 13:32:53 EDT 2013


Fred,

Only U6 is socketed, all the rest of the Control board ICs are to be 
soldered.
If the builder followed instructions, the EEPROM U7 would be soldered 
directly.
You are quite correct, sockets sometimes give trouble.  Usually removing 
U6 from the socket and re-inserting it will wipe the contacts 
sufficiently to clear any oxidation that may have occurred during storage.

73,
Don W3FPR

On 4/17/2013 1:03 PM, Fred Townsend wrote:
> Don: I do not own a K2 so I am shooting in the dark. On the other hand I
> have designed and trouble shot circuits of this kind. Your analysis seems
> dead on. Following your lead, are U6 & U7 socketed? If so the symptoms sound
> very familiar. It's caused by soldering flux residues migrating to the
> contact area of the socket. Time and temperature cycling can make this
> happen. If true the sockets may need replacement. If removing and reseating
> the chips changes calibration it is a dead giveaway. The chips can be saved
> by cleaning in alcohol but cleaning the sockets is almost impossible. Just a
> guess.
> 73
> Fred, AE6QL
>
>



More information about the Elecraft mailing list