[Elecraft] RE: K1 # 1605

[Morrow, Michael A.]

Chris wrote:

> I have only 1 trouble with the filters : when I use XFIL to change
> filters : I start from FL1, after FL2, and finally FL3 : but when I
> reach FL3, all the keys are locked and it is not possible to change =
any
> function , except by a power off. Same problem when I try to change =
the
> filter bandwidth in the MENU : I am able to change the bandwidth for =
FL1
> and FL2, but when I switch to FL3; all the keys are locked. Is that a
> known problem, ou do I have something else wrong ?

Chris, this is definitely *not* normal. =20

It almost sounds like there's a problem somewhere between the front =
panel MCU (U1) and the D/A converter (U2).  Can the CW sidetone be set =
with STP through all available values without acting up?  Can the =
transmitter power output setting be varied without trouble?  I believe =
the same output line from the D/A converter that biases the filter =
varactors in receive also produces the CW sidetone in transmit, while =
another output line from the D/A converter controls the transmitter =
power level.

Is the output of voltage regulator U4 constant near 6.0 volts?

I think I would go back and look very closely at all solder connections =
on the front panel board, especially for U1 and U2.  I'd also look very =
carefully to see if all the pins of U1 are seated properly in the IC =
socket.  I'd also listen for the front panel MCU oscillator at about =
3999.5 kHz (using another receiver whose antenna wire is positioned near =
the MCU) when the unit locks up to see if the MCU oscillator has =
stopped.

Of course, it'll probably be something completely unrelated to the above =
that will be the problem.  Please keep us posted, for it's a problem =
I've never seen anyone report on this list in the 2.5 years since K1 =
deliveries began.

BTW, it took me about 25 hours to build my K1.  Just slow, I guess.

73,
Mike / KK5F
K1 No. 175 =20