Ok, so the 44260 gives minimum surge protection while letting voltage variations through to the voltage regulator, and if you get a surge that passes through the 44260, it will possibly fry the VRSG but the 44750 or the 34830 will protect your tt. It seems it would be better if the 44750 or 34830 would let through voltage variations to the VRSG and then you wouldn't need two surge guards.
About your circuit board, maybe you can find someone third party that could repair it at a reasonable cost. At work, we've had some fried components on our automation boards and found someone to rebuild them cheaper than the manufacturer or replacing it. I'll look up the company. It won't be until next week though, I'm on vacation.