Just finished doing this. Interconnect board from radios head to main body. You have to remove the 2 screws on the control head to get to the interconnect board.
Take your your 6058's and 6066's and isolate pins 4,5,22,and 29. I just un-soldered them. To find these pins, look at your interconnect board while it is still in the radio after taking off the control head. They will be the pins at the top of the board, not to be confused with the lower black plug which the control head mates with.
Starting from the top row of pins at the very left which will be pin 1. As you get to pin 6 you will see that pin 7 is missing and then continues to pin 8 all the way to the far right which will be pin 19. Pin 20 starts at the bottom left bellow pin 1 and proceeds to the far right which will be pin 38.
You can cut the traces to each pin or just unsolder it and remove it like a bad tooth.
You now have an HLN6285.
I just did the mod and it worked like a charm, a viable radio I chucked a few days ago was rescued and is now is working great.