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Troubleshooting GPS 175 instal.

M

Mousse

Well Known Member
Help needed from avionic gurus of VAF. I powered all my avionics for the first time in my a/c yesterday. All except the GPS 175 performed well. The GPS 175 however blows the breaker only when the unit is its rack. No short if the unit is out. Any suggestion how to test this. All pins in both connectors seems ok. Is it my installation of the unit itself. All help greatly appreciated.
Michel
 
Well, the odds strongly favor that you put a pin in the wrong hole. It’s very easy to do. But now that you applied power, you may have damaged the unit, too.
Start by tracing each and every wire, and what hole # it’s in. Use a bright light and magnifying glass, and/or count holes from the end. Maybe get a second set of eyes. If you find a problem, fix it and try again.
After all this, send the box in (hopefully under warrantee).
 
I fought a similar problem on my GPS175 install: worked fine when plugged in outside the panel. but failed or was intermittent when installed in the rack, even though the unit seemed to be fully seated properly. I removed the rack mounting bolts to eliminate any twisting or warping of the rack, and re-installed with the unit in place and it's worked fine ever since. Still can't understand why this happened when the Db connector appeared to be fully seated....
 
I ended up jamming some pins on my radio with a 62 pin condensed connector by accident. Make sure the pins are not bent. Then make sure your wires are correct. If it works outside the rack then it likely isn’t damaged.
 
If you take it out of the rack and power it up right now, does it work?

I have a 175 and even I got the installation right, but I wired it up on its own, nothing else going to it. No audio panel, just straight power with the king 209, only 5 pins plus the 2 power and two ground pins and the worthless config mod pins, thats it


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Thank you all for your comments and recommendations. I will investigate further today and hopefully find the problem and report.

Michel
 
Update: Pin 21 (12v) found bent and touching the side of connector when unit in place. New pin to be installed, however the old pin didn't seem to lock in position and could be easily push out. Do I have to replace the connector of is it possible to lock the pin in position using some king of glue?

Michel
 
Mousse said:
Update: Pin 21 (12v) found bent and touching the side of connector when unit in place. New pin to be installed, however the old pin didn't seem to lock in position and could be easily push out. Do I have to replace the connector of is it possible to lock the pin in position using some king of glue?

Michel
Click to expand...
No glue...please....

If the pin doesn't seat, then you should replace the connector housing.
 
Depending on your crimping tool - It's not unheard of to damage the locking area of a pin - causing it to no longer "lock-in". After you re-pin the wire with a brand new (verified correct p/n pin) pin and confirm visually the pin is un-damaged - try inserting it into 21 again - hopefully it will lock normally & firmly. If not - then try it in a previously unused hole just to satisfy yourself that pin 21's hole in the connector shell may be damaged. Be sure you are using the correct PIN's, Be sure you are using good removal tools that do not damage the connector shell.
From your statement that the pin was bent & not locking - makes me suspicious.
Unfortunately - if backshell is damaged, then replacement with new is absolutely warranted.
 
Update: Pins 21 and 42 re-wired with new pins which are ok. But unit does not power up. 12v and ground checked ok so I suspect an internal fuse is blown. Contacting Garmin today. Thanks all for your inputs, it is appreciated.
Michel
 
How about forget the harness and connector and simply apply 12 volts to the unit where pin 21 or 42 connect, no need to power both to test it 21 or 42 will power it on, than apply ground to either 20 or 41 and than the unit should power up. I would do that before shipping it to get fixed. Anywhere from 9 to 33 volts powers it up, get some cheap 18g wire strip it and twist the end to fit in the 21 or 42 hole and the same for ground, should fire up. Or confirm broke. Wired mine up to a cigar plug in my truck without the connector, just stuck wires in the holes and put tape over them to hold them in place, to test it out before I installed it in my plane
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Update: Put the unit in its rack again and would not power up. Then realized that unit disconnected from avionics bus. Connected power wire to bus and it WORKED. The obvious was hitting me in the face and I couldn't see it.
Thanks to all for your help.
Michel
 
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