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G3X Testing & Power Up Issue

jMINTj

Member
Good afternoon all,

Looking for some quick assistance from anyone with G3X experience. I recently purchased a used G3X Non-Touch. I figured I'd get them while they are still available since I hate touchscreens, I like the Garmin line, and plan to go that route with the rest of my avionics when I get there.

My question is this: Are there any gotchas regarding power-up testing? I haven't gotten to that point yet. However, I have my multimeter out and am testing continuity between the Aircraft Power pins (31 & 32) and the Power Ground pins (15 & 16) to make sure the unit functions, but I'm not getting any continuity from either Power Pin. I also am not getting continuity between the Config Module Power Out & Ground pins (the only other thing I can think of that uses power provided by the unit on the harness, pins 17 & 49). I want to make sure I didn't get a dud. Any advice? Thanks in advance.
 
According to the Garmin experts in the class I took. Switching power and ground is about the only way to damage a unit with 12 Volts. They also warned us about powering up for the first time on a battery that might die during the initial software loading.

Get the manuals and follow them. They have detailed instructions on powering the units up for the first time.
 
More Immediate Question

Leo, thanks for the info. I have the manuals and while I haven't read every single word, I've put in a decent bit of time browsing through. I saw the extensive setup/powerup section, but that is still a little ways off. I'll keep in mind the two big points you mentioned.

I'm still looking for help with the more immediate question of "Did I get a dud?" My multimeter is not reading any continuity between the Aircraft Power and Power Ground Pins in any configuration. Did anybody else that purchased a G3X (maybe used) test for functionality this way? I have a bench testing meter with variable outputs on the way and (as Leo mentioned), I don't want to test without a controlled power source.
 
I think most folks, myself included, are confused about what you are trying to accomplish. Are you looking for continuity on the unit itself (GDU370 I assume) between the power and ground pins? If so that's a meaningless test. If you want to test the unit simply apply 12-14v and ground from a good battery to the appropriate power pins and see if it boots up!
 
Walt, you're right. I guess I was just too cautious and not wanting to mess up my "new" (and expensive) unit by plugging it in without protection so I figured I'd just try to test it before plugging it in. I figured I'd treat it like a circuit, assuming there'd be continuity in the GDU 375 unit between the power and ground pins.

Got a response from the G3Xperts and they pointed out that continuity between the power and ground pins would short the battery to ground. Ok, that makes sense now. Keep in mind I'm still learning wiring and circuitry (going through the Aeroelectric Connection between building), so I'm still a bit overly cautious and obviously have a lot to learn.

But sure enough, I grabbed an old 12V battery, attached a couple d-sub sockets to it and the G3X fired up with no issues, from both power source pins. I feel a bit foolish at this point, but that's how you learn right??

By the way, this is a good note to self to be careful with "ground" and the many different ways it is used.
 
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