Repair or Replace Autohelm ST7000?

[Whitebread117]

42' monohull, 28k lb displacement, cutaway forefoot shoal full keel, skeg rudder, center cockpit.

I bought the boat with a nonfunctional ST7000 quadrant mounted AP and a S4000 wheel mount unit. The 4000 is fine for motoring in calm water- it's useless in any kind of swell or under sail (heavy boat, likes 15kts + sailing).

The ST7000 head unit doesn't power up when power is applied. Before I spend too much time on it, is this unit new enough to be worth repair? I'm not in front of it now, just budgeting boat projects for the next couple months.

All I'm after is an AP that will hold a rock solid compass course in any reasonable sea state. We navigate with navionics and a couple tablets- I'm not looking for any AP interfacing. We're a power hungry boat with multiple charging means, so efficiency isn't highest priority.

So is a ST7000 worth repairing for an overweight 42' cruising monohull, or is there a better option for a simple robust AP?

(Wind vanes are out, no room to mount and no passages longer than 48 hours for now)

I like saving money, but I'm willing and able to pay for a better product if one is available.

Thanks!