If the TX light comes on it is indeed in transmit mode. You are taking the PTT line to ground somewhere.
check all of your connections that there is nothing shorted at the connector and nothing is touching where it shouldn't be touching. No solder bridges.
I've made many of these cables
and a stray strand of wire can be a real pain. In all honesty if there is a commercial
cable available it's worth the $20 to not have my old eyes strain and shaky hands try to fight those connectors for me.
However, it's easy enough to do if your hands are steady and your eyes can see well enough to solder to the connectors.
Often it is not possible to use more than one connector at the same time on some devices that don't have good isolation. I've run into that more than once as well. In this case sometimes it can be a challenge, but still doable.
It's very easy to get your wires crossed so to speak. Something you want to check very closely is the pinout and remember that it is often as you look into the connector on the equipment
, not the end of the cable so everything is 180 out like a negative photograph. It helps me to draw out the connector and write the numbers down, if your cable has colors match those with the connector numbers so you've got everything right when you get to the other end.
if you are 100% sure everything is right on the 13 pin din, reverse polarity on the mono plug and give it a go.
Before starting over, check all the software
settings. Some use RST/DTR for TX, They may be checked causing the software
to key the radio
. One way to check it is to power off the machine and plug in the cable. If it isn't in TX when the machine is off the software is keying it. Otherwise you have a grounded TX circuit in the cabling.