Flakey CDI

murphey

murphey

Touchdown! Greaser!
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Aug 21, 2008
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murphey
I've got a digital CDI - the MC60 from TKM when they were making such things (they've since abandoned and disowned it). Definitely not working so it's time to replace it. I was looking at the GI106B....outlandish price when the GI-275 or the G5 in CDI mode isn't that much more.

I don't get it.

PS - I already have the G5 HSI talking to the GPS 175. But as I mentioned in an earlier email, GPS went bye-bye today in the Denver area. Fortunately a beautiful VFR day. The shop that installed the GPS wanted to connect the CDI to the GPS, which I refused - I don't like single point of failure. Which meant today, my SL-30 with the LOC indicator worked perfectly because it didn't need the GPS on approach. But it would be nice to have something with ILS for backup with the SL-30.
 
If the GPS side of a 430 rolls over dead, do you also lose the functions on VLOC?
 
Is the SL30 a digital box or analog? You can't run it to the G5 too?
 
NealRomeoGolf said:
Is the SL30 a digital box or analog? You can't run it to the G5 too?
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I don't like single point of failure. Turned out to be handy this past Saturday, when GPS was gone around the Denver area, the G5 HSI didn't work. But my SL30 with the built-in localizer worked like a charm. Hence the replacement CDI will talk only to the SL30 by my choice
 
I guess the 175 is GPS only, right? No nav? Then you wouldn't have green needles, only magenta. If the SL30 was wired into the G5 you would've had green needles available on the G5. But if you don't want a single point HSI then it is what it is. I've got my 530 and 255 wired to the G5. Guess I'm living on the edge. ;)
 
NealRomeoGolf said:
I guess the 175 is GPS only, right? No nav? Then you wouldn't have green needles, only magenta. If the SL30 was wired into the G5 you would've had green needles available on the G5. But if you don't want a single point HSI then it is what it is. I've got my 530 and 255 wired to the G5. Guess I'm living on the edge. ;)
Click to expand...
G5 HSI is wired to the GPS 175.
The other CDI is wired to the SL30. That's the CDI that's not working. That's the one I need to replace. And when the GPS went out today, I still had the SL30 working.

I see 3 options
1) Another G5 as a second HSI
2) Conventional CDI with LOC/ILS
3) GI 275

#3 is too expensive for me right now, after spending the $$$ on the HSI and 175.
#1 & #2 are about the same price even with install if I buy new. If I pick up a used #2, might be more cost-effective.
 
There would have been no loss of NAV functionality if both the gps175 and the SL30 were wired to the same HSI, with a gps signal outage. If finances are tight wiring both to the G5 is going to be the most economical fix and a separate CDI can be added later.

There is only $100 difference in price between a GI275 CDI and a new GI106. The full featured GI275 HSI is more expensive and dealer only. Used indicators are an option but there are only a couple I would consider installing and prices remain high on them because of the spotty availability of new avionics right now. Availablity might also push you to wiring to the G5 for the time being unless you are willing to wait for an extended period of time.
 
murphey said:
Please explain "green needles"
Click to expand...
When the G5 HSI is displaying GPS info, the needles are a magenta color. When it is switched to the SL30 (VOR/LOC/GS) the needles are a green color. A GPS outage does not fail the G5 HSI. Even though it won't display info from the 175, it will still display data from the SL30 via "green needles". But since you never connected the SL30 to the G5 HSI, it had nothing to display once the GPS went out.

BTW, the installation manual says you can't connect the SL30 to both your G5 and your MC60.
 
asicer said:
When the G5 HSI is displaying GPS info, the needles are a magenta color. When it is switched to the SL30 (VOR/LOC/GS) the needles are a green color. A GPS outage does not fail the G5 HSI. Even though it won't display info from the 175, it will still display data from the SL30 via "green needles".

BTW, the installation manual says you can't connect the SL30 to both your G5 and your MC60.
Click to expand...
No intention of doing this. The MC60 is going away.
 
murphey said:
No intention of doing this. The MC60 is going away.
Click to expand...
Connecting the SL30 to the G5 is literally just 2 wires plus ground. But if you go that route then you aren't allowed to connect up any other CDI to the SL30, MC60 or otherwise.
 
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