Pull-ups or no pull-ups

All,
I am trying to decide if I need to install any of the 10K pull-up resistors for the OBS, ILS, etc. analog inputs (B18-B21). I am installing the tray and all of the wiring for a 430 but don?t plan on actually buying a 430 until sometime down the road. The idea being that I will have enough new toys with which to play for a while. It sounds to me like I need to install the 10K pull-ups now and disconnect them when I install the 430W. Is that correct?

Thanks,

?

to what are you wiring?

how is everything coming along?

Ok, my bad. I originally wrote this to post on the GRT forum and assumed everyone there would understand the context. Perhaps this is why I haven't had any responses. Thanks for bringing it to my attention!

I am wiring a dual screen GRT (one HX and one HS) to my radio stack. The stack will eventually include a 430W; just not in the beginning. There are 4 lines that the GRT manual says need a 10K pullup resistor if they aren't attached to a "nav head" or "other?" device. I wasn't sure if the 430 counts as a "other" device. I am thinking the GRT doesn't like these inputs left floating (thus the pullups).

Things are coming along; but slowly. I am chest deep in wiring and being reminded why I call myself a "recovering engineer." I hope to get back on the wagon soon! Actually, I am enjoying this part. But I am itching to get it all done. But, I am expecting busy fall. So, the prognosis for progress is problematic (hows that for alliteration? ).

How about you? Been flying anywhere interesting? How is work?

Probably should ask GRT on this - while you absolutely need the pull-ups for the WS/HS models, I noticed a setting on the HX where you can turn internal pull-ups on/off. No explanation of what that is, but I suspect that's for the analog inputs so that a personal doesn't need the ones shown in their wiring diagrams.

Bob
RV-10 N442PM

Darn!

I thought this thread might be a solution for bathrooming activities on long cross countries!

You know, when I wrote this I thought about that mis-interpretation. But then I thought, no one but me would think that way. Well, Frank, welcome to my world!

Bob, thanks for the info. That is nice to know about the HX. I will check with GRT. If it is true, it would be a big help. Also, since these inputs are common to both my HS and HX, the HX (if it has switchable internal pullups) would be taking care of both units.

Thanks,

progress

sounds like you might need a motivational visit. you are sooo close!! at any rate, glad to hear things are moving along. . . if slower than you'd like.

things ok down here. 141 hrs so far, accident & fatality free. made a trip to michigan in the spring, and made oshkosh. flew a transport for pilots & paws this past friday. so you have great things to which you can look forward!

James,
That's great! You have made some nice trips. I have never heard of Pilots & Paws. But I can guess what their mission is and it sounds like it would be a great organization. Sounds like it could be a challenge, though. Thinking back on how much trouble my pooch had just traveling in two dimensions, I suspect a third dimension would have really messed with her! Thank God for acepromazine (sp?)!

Hey, anytime you are up for a short hop to middle GA let me know.

From the horse's mouth...

All,
Here is the response I received from GRT regarding the pullups:

*******
The HX does have programmable pull-ups. This is in the Set Menu, General Setup.

You will need the pull-ups at all times, especially when connected to the 430. Without the pull-ups you will damage the 430.
*******

Interesting, that the 430 could be damaged without them. Not something I would have guessed.

Tony