I think a borescope will give you a good idea if there is a need to look further.  The inspection panel can ease access and repair for sure.  We have seen some issues, most recently on a 1000 with some ugly cracks in stiffeners.  I’d not seen it before, and while repairable, it’s unfortunately a new owner inheriting the problem.  What led to the discovery was the dorsal fin related corrosion and that skin replacement which require the leading edge of the of the vertical to be removed. So I do not want to go through another buyer’s inspection without removing the dorsal that has a propensity to trap moisture. 

My 3100 Autopilot;
This past weekend, i fired up my electic APU and ran the autopilot for well over 90 minutes on the ground without any failure.  I know there isn't any wind/force resistance on the plane sitting on the ground.  I was making it descend, ascend, hold altitude, I tried pretty much everything i could think of; even tried grabbing and putting force against it with my arms, etc.. The unit just wouldn't create the failure like it did on my last few trips.  I know if I attempt take down to the avionics shop (less than 60 minutes) this unit will not fail as it knows it is going the avionics shop.   I guess we still might do that and just start trying to replace parts with loner parts to see if it fixes the failure issue. Either that, or i could try and pretend to file a flight plan and pretend to travel somewhere else, and then when it fails, we take a quick detour to the avionics shop?

Just thought i would share this morning.

Now that IS&S owns the 3100, I'm not sure what the future holds. Hopefully they are keeping the team in Mineral Wells.

Yes, very quiet in here the last half a year for sure.
We have had some issues with our 3100 Autopilot we are trying to troubleshoot.
This might be the wrong area to post, but what the heck.
We will get about 40 minutes of working autopilot in the beginning of the flight, and it will just disconnect and say Auto Failure.  It then clears and we can use the flight director portion and manual fly the bird.  Whenever i try and hit the autopilot button, it tries to engine the servos but then without 1 second it disconnects and gives the same message.
I have taken it to the shop and of course the autopilot works perfectly fine both down and back from the shop (1 hour flight each way) We have changed out the AHRS box and it acts the same way, so it can't be that. I need it to fail down at the shop in order for them to properly troubleshoot, maybe i can set it up on an APU for an hour or two with the autopilot engaged and hopefully it will fail and they can then figure out what is causing this failure.
It's been working decent for about 2 years since we put it in though, and just started to act up in the last month or so.  Got about 15 hours in the last month hand flying it, so getting used of the old days of hand flying commanders when those Bendix M4B autopilots would fail all the time - actually very easy to hand fly commanders and is an non issue for me, and I do find it less boring, but it's harder to eat a sandwich when hand flying.
Just thought i would share with the group as it is pretty slow on here lately, and to see if anyone else knows about the 3100 as they are in many commanders now. 
thanks
corey

ahhh yes "HAPPY WIFE... HAPPY LIFE" I AM FIRM BELIVER