Hi all,
It turns out that pin 17 on U2 has an undefined voltage.
When NOT selected that band (40/30M) it must be 12V. I measure 7V.
The input for this switch is pin 2 at U2 Here I measure 0V (=good) and
goes HI (5V) when selected
So U1 is working well
Will heading tomorrow for a new U2
Peter
Don Wilhelm schreef:
Peter,
The fastest way to determine if you have a problem with the Low Pass
Filter in the KPA100 is to check it with an antenna analyzer.
Disconnect the small coax to the K2 RF board and terminate it with a
50 ohm (51 is OK) resistor. Power only the base K2 (the ribbon cable
must be connected). Then switch the K2 to the band of interest and
connect the antenna analyzer to the SO239 antenna jack and sweep the
band. If the SWR in the band is about 1:2, then the Low Pass filter
for that band is OK. If something is wrong, you will see a much
higher SWR.
An analysis of the sweep results along with a look at the schematic of
the relay contacts should reveal whether you have a bad relay.
73,
Don W3FPR
Peter wrote:
Hi
After a few years of good service,I have a problem with the K2 output.
I have the K2 with K2/100.
The barefoot K2 put full power out on all bands via the bnc connector
When I connect the K2/100 with PA off with the menu there will be low
power on the ant connector on the higher bands (15/12/10 meter).
Since 10/12/15 are combined, I suspect the bandpass filter
I tested from TP2 and ANT. out and see NO interruption when change
to an other band.
All C's, L's and solders look good.
So I guess there will a bad relais thats stay ON when I go to 10/12/15M
The relais in the BPF are N.O. when not selected, right?
If so, I can measure between de N.O. and COMMON to see if the
connection goes away
Futher more, there is 12V at U2 (pin 14 18,17,16,15,14) when the
relais in NOT selected. If selected the needs pin good down to 0V,
right?
Any other thing to look at?
Peter
PC2A
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