Uniden grant i have uniden grant that stays keyed up even with out a mic on it how do i fix it

I had this same problem on a Realistic Navaho, TRC-30A that I purchased in the mid 70's (I still have it by the way).

The cause of my radio to do this was a shorted diode in the keying circuit on the main board. The shorted diode effectively did the same as keying the microphone.... without the microphone being connected.

You need to find the schematic for your radio and check for shorted components on the keying line. If you don't have a schematic, you can unplug the radio and use a ohmmeter and check for a shorted diode or transistor in the keying circuit.

Please let me know if I can be of further assistance to you.

Good luck!
- Jim