[Elecraft] [K1] Internal Noise Bursts every 12 seconds or so

[Mike Morrow]

Bob wrote:

> Even though the second CPU on the filter board is mostly inactive, no
> telling what internal loops are going on that might result in it turning
> that 4 MHz resonator into a periodic signal.

In addition to the relays on the filter board itself, the PIC on the KFL1 board controls RF board relay K1 (the RF Attenuate ATTN relay).  But that info is not likely to help isolate the problem you report.

I own K1 #175 that I built in November 2000.  It was unfortunately a lightning strike victim a few months ago, ending almost 15 years of service.  A most excellent radio for all thoses years.

I have never before read a report of a problem similar to what you describe, except for one in 2001 in which a burst of internal noise was generated on 20m after going from transmit to receive.  This was caused by the PIC on the KNB1 noise blanker PCB, and1 was corrected by adding a 0.01 uF capacitor on the PIC's Vdd line to ground.  It's a long shot, but you may want to check the installation of the similar capacitors on the Display PCB (C4) and KFL1-2 (C27).

Mike / KK5F