Garmin G5 HSI troubleshoting challenge

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Baron62

Pre-takeoff checklist
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Oct 31, 2016
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Baron62
My airplane just came out of an avionics upgrade that includes a G5 HSI with GMU-11, GAD-29B plus a GTN 650 and unfortunately the G5 heading bug does not drive the Century 21 autopilot correctly. In GPSS mode the AP follows the DTK nicely. I will be calling the shop in the morning to have them fix it, but I was wondering if you guys had any ideas? I will also be checking the 650 and G5 config settings.

When in HDG bug mode:
1. moving the heading bug left or right of the mag heading does not turn the yoke unless you go left of right of a totally different arbitrary bearing. (HSI heading does match wet compass)
2. the arbitrary bearing changes when I activate different flight plans/DTKs (in HDG bug mode!, not GPSS)

There really isn't a lot of wiring as shown below.

upload_2018-2-13_20-10-57.png
 
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Does the "arbitrary heading" align with the course pointer?
 
GMU 11 not calibrated right?


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Axtel4 said:
Does the "arbitrary heading" align with the course pointer?
Click to expand...
No, it does not align with the course pointer. I am wondering if the DG Select ground on the Century 21 AP CD185 pin 17 needs to be removed becuse I am going from a DG to an HSI.
 
WannFly said:
GMU 11 not calibrated right?


Sent from my iPhone using Tapatalk
Click to expand...

It appears to be calibratred correctly. G5 HSI mag heading agrees with the wet compass.
 
did you figure out what was wrong?
 
I have not returned to the Avionics shop yet because I am waiting on the Garmin 796s to be in stock at the end of the month and do both at one visit. I believe the problem is due to the Century 21 AP "DG Select" ground not being removed. The shop followed the Garmin install instructions, but I think they are incorrect for an airplane going from a DG to an HSI. Hopefully in 2 weeks I will get back to the shop. The GPSS steering has been working great. Very nice feature. I will update the findings after we remove the DG Select ground.
 
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My G5 HSI just died completely. The display will not come on at all. Not with Battery bus power or with the unit power button. For some reason the shop connected the G5 HSI to the Battery bus instead of the Avionics bus. I will be calling them tomorrow to schedule an appointment.
 
FWIW, my G5 HSI doesn't power on reliably as the G5 PFD. Typically, if I'm getting in the plane for the first time in a week or whatever, they both come on as they're supposed to. But if I'm in there screwing around with settings, or fiddling with switches, turning them off and back on, the HSI won't turn on simultaneously with the PFD and requires holding the power button for a while until it decides to come on.

This isn't a case of a loose wire or anything, as far as I can tell, it's just the realization that behind that pretty screen is probably rushed-to-market code or god knows what.
 
My G5 HSI is up and running now. It turned on and gave me a " Low Battery" alert. I checked the level and it was near 0% charged. I flew the airplane and it charged to 100%. I think I might have rushed the 3 second power off sequence and inadvertantly left it on until it was fully drained. If the unit does not discharge again, then the G5 HSI failure was due to me.

The heading bug issue is still there until I can make it up to the shop.
 
jimmyjack said:
FWIW, my G5 HSI doesn't power on reliably as the G5 PFD. Typically, if I'm getting in the plane for the first time in a week or whatever, they both come on as they're supposed to. But if I'm in there screwing around with settings, or fiddling with switches, turning them off and back on, the HSI won't turn on simultaneously with the PFD and requires holding the power button for a while until it decides to come on.

This isn't a case of a loose wire or anything, as far as I can tell, it's just the realization that behind that pretty screen is probably rushed-to-market code or god knows what.
Click to expand...
I am running into the same with the G5 not powering on reliably when turning it off then back on. Someone on another thread said it was a known issue and if you hold the power button for 10 seconds it will come back on.
 
The Heading bug mode now works correctly. The C21 AP now follows the heading bug. The problem was resolved by removing the ground jumper connector on C21 AP pin 17 (DG select) in diagram above so that the AP would operate in HSI mode. The garmin G5 install manual was incorrect because it said that this only applied to the C31 and C41 APs. Now I can move on to testing the C21 AP NAV mode to make sure it follows the VOR and localizer.
 
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Got me thinking... wonder if the new Garmin set-up will work with an old Cessna 300A wing leveler?
 
They told me no so I ordered a gfc500
 
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