The soldering skills aren't terribly demanding to fix it yourself. I've sent a transmitter to Airtronics twice for repair and have gotten about a week turnaround time. Once was for a broken battery connector on the circuit board of the RDS8000, and the other was because the SD-10 won't work with the Real Flight simulator. BTW, I found out after $25 worth of shipping both ways that it isn't capable of working with any simulator because the voltages of the trainer port are different. The Airtronics tech could have just told me that had he known.

As for trading up or not, look at it like this. You can probably repair the transmitter you have and sell it for about $40. So the SD-10 package will cost you $320 total when you allow for the real world value of your radio. Or you could apply that money to a different radio in the same price range. The $300ish price slot is extremely competitive, so there are lots of good radios to choose from. If you believe the best value is in Airtronics, then go with it. If not, go a different route. I do realize you have receivers to deal with too, but they'll sell on the used market too.