Warning for those that run Rangers with an internal amp.

A beta matched set of transistors would be the way to go. For peak performance it would be worthwhile to tweak the bias voltage of the final stage for maximum linearity between it and the previous stages for minimum intermodulation distortion. If no adjustment point, then changing a resistor value to alter bias voltage would work. Ham guys might tell you "It doesn't matter" because their bench is unable to see those minute details I suppose. For best results it would be worthwhile to buy a beta matched set of 8 transistors from RF Parts and take four of them and put them in a safe place so that the next time something like this happens you have easy drop in replacements with the same beta code so that no adjustments would be necessary.

 

By the way thanks for the valuable lesson. The next time I jump start my vehicle I'll be disconnecting my radio

 

RCI uses proprietary transistors and the ones you purchased are definitely not a drop-in replacement.
I'd venture to say that you're asking for problems putting mismatched transistors in there. Just because all four have the same part number doesn't mean the supplier put them on a curve tracer and matched them accordingly. It's possible you might get lucky with minimal IMD.
I don't care for the odds though since I'm not exactly a gambling person.

 

Is this what you got? If so it looks like a pretty good deal.

 

What you want is an auxiliary battery relay. They are rated for continuous use.

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TA