If the OP has followed the
exact steps as outlined in post #6, that would conclusively identify whether or not the SD card is the problem. Since the OP reported that the screen doesn't come on at all when he tried that, that entirely eliminates a bad SD card as the source of the problem.
In a properly functioning Home Patrol 1, if you remove the SD card completely from the scanner and power it up with
no SD card installed, (with a known good set of batteries and not connected to a computer), the screen will come on, and show the SD card error on the screen for about 10 -12 seconds and then the scanner will shut down. This test completely takes the SD card out of the equation.
The OP's replys to that test were:
The screen does not even come on .
I have tried to turn it on without the card no go.
.