Re: uBITX woes, feeling disheartened. #ubitx

Jerry Gaffke

I have no idea what your sets of pins are. 
Read this post to understand the relay pin numbering, 
and how the rail labeled "TX" gets connected to 12v when you press the PTT switch to transmit.

When receiving, the relay contacts are as show in the schematic.
Pin 8 of K3 is not getting power during receive, so it is zero volts and the relay is not energized.
M1 and M3 are low level received audio, and should be close to zero volts.
The antenna at K3-12 is connected to K3-14 from which the received signal continues on through K1 and into the receiver.
The antenna also has a low level signal, and you will see close to zero volts on those pins too.

When transmitting, the TX 12v rail powers the K3 relay coil by putting 12 volts on pin 8.
M1 and M2 get disconnected when the relay is energized, in hopes of somewhat reducing the PTT  audio pops.
The antenna is connected to the IRF510 power amp through K3-12 and K3-16, there will be perhaps 30 volts RMS of RF signal
on pins 12 and 16 while transmitting, though the signal is centered on ground due to the transformer at T11, your DC voltmeter won't
accurately show what is going on there when transmitting.  The meter will likely read around zero volts, though the strong RF
transmit signal could conceivably damage some meters.

On Sat, Feb 3, 2018 at 05:53 pm, @AC8XZ wrote:
hello all  First poster;   k3 suppose to have voltage all the time?  on rec first set of pins have none. second set/3 have 11.8 v last one no voltage. on trans.1st third and fourth set of pins have11.8v. I can hear ke clicking when I hit ppt.   AC8XZ

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