I have a Kenwood Ts 520 transceiver that the 12V inverter has stopped working. I tested everything and the only thing suspicious was a transistor. They both tested good with a ohm meter. So I tested the hfe. One tested 60 which is what the data says it should be, but the other one tested 506 gain! I did the test twice so I think it's correct. I priced transistors but they are $25 each! Can I substitute. 4 5305 mosfets in parallel?