dual GI-275 + Century III install/interface issues

[cowman]

So, my Lance has been in the shop for almost a month now getting my AI and HI replaced with GI-275s and having those interfaced to the original Piper Altimac IIIC(Century III) AP.

This was originally going to take a week but the installer ran into issues with the AP interface, apparently it was way more complicated than they expected. Said they had to get out a breadboard and basically build a custom board to get it done which is why it's taken so long.

Supposedly they have it all put together and are configuring/testing now so hopefully I'll have it again soon... just wanting to see if anyone else has seen issues like this and generally share intel on it. Shop is really apologetic that it took this long, apparently this is the first(and likely last) time they've interfaced one of these with a Century III.

I have a better than average understanding of electronics but I'm no avionics tech and don't necessarily know what's normal for these things. It really surprises me Garmin would advertise these things as compatible and not have some kind of interface box available though.

 

[Bill]

We were quoted a month for two GI275, a GNC255, and a new audio panel. The Garmin stuff connected to the legacy KFC 200 Ap. It’s coming in right at a month!

 

[Jesse Saint]

There is a Deklin box that does most of what they probably breadboarded, probably. Sounds like they are fairly new to avionics of this type.

 

[Jacob Kinsey]

As Jesse mentioned they should have got a interface box from Deklin instead of building the transformer isolation circuit.

 

[MajorTurbulence]

When I got my Aspen about 10 years ago, my Piper Autocontrol 3b (Century 2) autopilot was very brisk in correcting the heading in heading mode, but less so on GPSS. After calling Aspen, we needed to fine tune the excitation input to adjust the gain. This was done by changing the resistor in a little bread box that was connected via the Aspen and autopilot that I never realized was part of the initial install. So I guess most of these new AIs and HSIs need some sort of connection box when interfacing with legacy autopilots.

 

[cowman]

There is a Deklin box that does most of what they probably breadboarded, probably. Sounds like they are fairly new to avionics of this type.

Just to update the thread for anyone looking, I informed them about that box and the person I talked to(who was not the tech doing the work) had heard of Deklin and even knew someone who works for the company! I think the discovery this was an option caused a lot of consternation. They ended up getting the box and basically re-doing the install, I'm also informed there is one less tech working there and I didn't ask if it was a voluntary departure or not.

They apparently had installed quite a few gl-275s without much trouble but this was the first time they'd connected one to an older autopilot. From what I'm told they don't plan on doing one of these again. Anyway after dropping it off on July 5th with a one week work estimate I was informed they had a successful test flight on Fri(about 6 weeks later) and I'm hoping to pick the plane up Tues after they finish up the paperwork.