Dave,
If it does not have the popping sound when you select 8R=nor, then run
it that way.
With the updated KPA100, there is one resistor on the bottom of the
board - a 22k from the +12 volt rail to the drain of Q7.
What a 100k resistor would be doing on the bottom of the board, I have
no idea. Perhaps it is contributing to your popping condition.
The KDSP2 has mute transistors and apparently the unmute time for them
(in addition to the audio delay through the DSP) is causing that pop to
be heard.
73,
Don W3FPR
On 7/3/2013 11:09 PM, DaveVK wrote:
Don,
I have fixed the mechanical buzz from the SSB tx on the KPA-100. The fault
was mine. Across the RF Aux input between the PCB and the heatsink there
seems to be a blue resistor with the colours Brn-Blk-Blk-Org-Brn with one
leg that was touching the heat sink. The legs are long and so I just pushed
it away with a screwdriver. I don't know what that part is doing there, or
why it is installed like a hack did the job but the memory of it is lost in
history.
I cannot find the part listed in the KPA instruction manual or any of the
upgrade kits. So maybe it doesn't belong there??!! But anyway, that problem
is fixed and the next time I'm in a position to remove the heatsink I'll
install that part properly.
I seem to have the upgrade kit installed and the blue cores are in the
KPA-100.
Now the popping is unsolved. It seems to be connected to the DSP. The
popping is most prominent on bands below 20m. When the DSP is bypassed the
popping disappears. I am still hunting this one down.
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