Hi Don!
Thank you for good advice once again!
C75 in your K2 needs less capacitance. You can try several other 470 pf
capacitors (NPO disc ceramics or C0G mono capacitors) to see if you can
discover one that is on the low side of tolerance rather than the high
side (like yours), or you can
Hi!
I got suggestion from Rick, KC0OV, to check VCO control voltages.
1800 kHz 3,5 V
1960 kHz 7,5 V
1970- kHz 8 V
Other bands are well inside 1,5-7,5 V.
I search archives and found case where it has been below 1,5 V and that was
cured with additional capacitance in C75. I test with some other
Jukka,
You are on the right path. When the voltage is high, there is too much
capacity in the circuit and the VCO/PLL is trying to reduce it - but it
runs out of steam at about 7.5 volts and cannot change the capacity any
more.
C75 in your K2 needs less capacitance. You can try several
Yes, it really does 'fade out' - but it does so pretty quickly,
like, in 5 seconds or less. Kind of neat,
actually, it would be hard to design a circuit that does this on purpose!
Any band change or power cycle brings it back, and, it even comes
back all by itself, after a while.
The RX
Gee, it's been almost eight years of nearly continuous, flawless operation!
But my K2 --just now-- decided to stop working on 160.
I was doing a little SP, looking for mults in the contest, and all of a
sudden, the receiver stopped working.
Doesn't transmit, either.
It's fine on other
Steve,
I have not seen anything that I would term 'fading out', but --
One of the first things I would do is to check the frequency of the VCO
while it is failing.
That can be easily done without dragging out your counter, just put the
internal probe in TP1 and use CAL FCTR - compare with the
Don
Yes, it really does 'fade out' - but it does so pretty quickly, like, in 5
seconds or less. Kind of neat,
actually, it would be hard to design a circuit that does this on purpose!
Any band change or power cycle brings it back, and, it even comes back all by
itself, after a while.
The RX
7 matches
Mail list logo
