Chapter 22 – More panel chicanery

I started out today with another round of in-depth studying on the GNS480 GPS unit.  I also tweaked some of the user’s manual as I did yesterday.  I also made up a decently long list of configuration changes that I needed to make to the GNS480 box.

Unlike yesterday, or the past week really, today I fired up the ‘ol soldering iron and got to work.  First off, I swapped out the MGL clock’s OAT probe with one of the ones I got in from GRT.  I had high hopes that a new probe would solve the issue of the MGL OAT consistently reading about 5° lower than the actual temperature, even though the MGL & GRT probes are within a couple of inches from each other (no joy, so back to MGL…).

The GRT HXr has 3 separate power inputs and it simply chooses the one it likes best power-wise and goes with it.  I thus have the HXr wired to the Main power bus, the E-Bus, and the TCW IBBS.  In the HXr install manual it states that when first powering on the HXr, to isolate each power connection to test out the power circuit.  I’ve been remiss in specifically doing this, so I took the opportunity to physically connect the HXr’s secondary power lead to the E-Bus and disconnect the HXr’s primary electrical input by removing the 3A fuse out of the Main bus.  Any power issues would then be noted upon power up [there were none].

I then pulled some LED Korry annunciator light boards out of some of the ON/OFF Indicator lights that run in the row above the main HXr EFIS.

After swapping out the LED light board for a 12V version, I then soldered a diode into the circuit on the GNS480 “GPS” annunciator light.  I did close to the same on the GNS480 “NAV” annunciator light, but also added a 300 ohm resistor in line.  Finally, for the “SUSP” annunciator light, I simply tested that with the 12V LED board sans the diode or resistor. While I had the connectors off, I took the time to label those wires that I hadn’t gotten to previously.

Since I already had my soldering “kit” out and ready for action, I went ahead and cut, labeled and then soldered the PTT leads coming out of the P5 connector to the pilot headset jacks, finishing off all the connections that need to be soldered to those headset jacks.

My final act on the panel was to move the HXr EFIS audio output feed from the designed (but not installed) proprietary Dynon EFIS input pins on the Dynon Intercom, and simply treat the EFIS audio out as any other audio feed as far as the intercom is concerned.  The big change was that I simply ran it into the intercom via the AMX-2A Audio Mixer.  I then cut and terminated a set of wires, labeled them and installed the twisted wire pair between the HXr EFIS (via the J4 connector) and the AMX-2A Audio Mixer.

Once my “chores” were out of the way, I fired up the instrument panel to check out all my updates and see how well they worked.  Plus –again– I had a number of configuration updates to input into the GNS480.

After I was done with all my checks and updates, I was going to take a few pics when I got a wild hair and decided to just film a video… so here it is:

Yes, it’s a bit lengthy (and bouncy) but hopefully it shows a glimpse of what I’ve been up to over the past week.  I have a few more minor electrical taskers to knock out tomorrow, but for the most part I won’t have a ton more of electrical stuff to do until much later.

I also updated a number of electrical diagrams as I was waiting for the video above to render.


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