Tony,
I would suggest that you use a 74xx07 Hex Buffer between the K3 band
outputs and the LEDs to show you the state of the band outputs. If the
0000 state for 60 meters bothers you, use a 74xx06 which inverts the
output so all 4 LEDs will be on for 60 meters.
Like Wes, I think you should trust the K3 band outputs and your efforts
would be better placed in lighting LEDs from the output of your BCD-14
band decoder to give you confidence that the band decoder is working
properly.
Of course, you could that with your DMM without building anything extra.
73,
Don W3FPR
On 1/27/2013 6:29 PM, N2TK, Tony wrote:
I would like to see (LED) the state of the BAND0-3 outputs. Has anyone built
or bought some kind of 4-indicator for this? I want to do this as a
temporary indicator while I am playing with a pair of UM BCD-14 band
decoders.
The BAND0-3 outputs come off of 5V through 2.2K pull-up resistors with a 220
ohm resistor in series with the output on the ACC socket. It would seem
standard 20ma LED's would not work here with the 2.2K resistor inline. Maybe
a diode inline to isolate with a separate supply on the LED's or use some
very low amperage LEDs or drive a Mosfet which drives a LED?
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