[Elecraft] K2 receiver going temporarily deaf

Mike McCoy [email protected]
Thu Apr 1 19:48:01 2004


"My troubleshooting technique on this scenario, seeing as he says it only
happens when the radio has warmed up, may be temperature related."

Actually I didn't say it only happened when the radio has warmed up. Of
course the K2 was on and had been for a while but I think that is just
circumstantial.

I really don't think it's a temp related problem.  When the receiver goes
'deaf' it does so very suddenly and and just as suddenly 'clears' itself
when it begins working again. It just doesn't have the 'feel' of a component
degrading due to heat over time (or vice versa).

Once a component quits due to heat (or cold) it quits. While it can indeed
recover due to the absense of heat (or cold) in the interim it wouldnt
explain how in the interim the K2 receives just fine if I disconnect the
coax shield AND that the K2 will suddenly start receiving again while it was
still warm (as it did the first time).

Someone mentioned a possible problem with the latching relays. This is more
in tune with the behavior I'm experiencing... it 'feels' more something like
that, i.e. a 'set/reset' type of condition. That's why I first thought of F1
(until I looked at the schematic)

But if it were a latching relay on the RF board wouldn't it be limited to
one (or two) bands? When the receiver is 'deaf' it's deaf on ALL bands.
Well again, except when I disconnect the (ground) shield. Then it receives
just fine on all bands.

I just pulled the Dipole down to check the center balun/insulator. That's
the only piece of the puzzle I don't feel confident saying is 'solid'.

Mike K5PU