Re: Pin Confusion #u3s


KI7MWA
 

Another question:  The diagram on page 15 shows +5V supply voltage applied to the PA pin, with the (upper) jumper connecting the PA pin to the +5V pin.  But, with the (upper) jumper installed, the +5V supply could just as well be connected to the +5V pin on the board, because with the (upper) jumper installed the +5V pin is in common with the PA pin. 

You could argue that the +5V supply HAS to be connected to the PA pin if one wants to install the (lower) jumper between the +5V pin and the Heat pin when you want to supply voltage to the oven of the TXCO (should you be using it). 

But if the synth board itself makes a connection between the +5V pin and the Heat pin (my DVM shows 0 ohms resistance between the +5V pin and the Heat pin when the synth board is in place), why would you need the (lower) jumper?

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