V3.0 pots R52 and R56

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V3.0 pots R52 and R56

Postby billr » Wed Sep 20, 2017 2:01 pm

When those are full-CCW is the wiper (pin 2) connected (minimum resistance) to pin 1 or is it connected to pin 3?
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Re: V3.0 pots R52 and R56

Postby kjones6039 » Wed Sep 20, 2017 8:03 pm

Where the he!! do you come up with these questions, Bill? Perhaps too much time on your hands? :lol:

Are you and I thinking the same thing? I will whip out my spare board in the morning and get you an answer. I am interested also.....

Ken
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MS2 v3 w/extra 3.4.2 Release
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Re: V3.0 pots R52 and R56

Postby billr » Wed Sep 20, 2017 8:10 pm

Thanks, it will save me from having to rip my MS out of the car and opening it. I'm just trying to understand that input better. Zero-crossing detection seems like it should be very simple and reliable, but I realize that circuit also has to accommodate Hall-type 0-5V as well. I'm just wondering how much it deviates from simple VR detect circuits shown in app notes from National and others. I gotta say... the direction those pots go should be on the schematic.
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Re: V3.0 pots R52 and R56

Postby DaveEFI » Thu Sep 21, 2017 12:58 am

Pot connection numbering convention has pin 1 as the 'minimum' end.
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Re: V3.0 pots R52 and R56

Postby kjones6039 » Thu Sep 21, 2017 8:14 am

As usual, Dave has the answer!

I wasn't too excited to go out to the shop this morning anyway......... when I saw the snow falling. :o

Ken
1979 Corvette - 383 CID SBC w/ Holley Pro-Jection 900 CFM TBI, 4-85 lb lo-z injectors & Walbro 255 pump
MS2 v3 w/extra 3.4.2 Release
36-1, Delphi LS2/7 coils in wasted spark, driven by v2.0 logic board from JBPerformance
Spartan Lambda Sensor from 14point7
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Re: V3.0 pots R52 and R56

Postby billr » Thu Sep 21, 2017 8:29 am

So, what is "minimum", CW? And, do these particular pots conform to "convention"? I have seen many devices (not talking about pots specifically) that go backwards to common convention... A little "CW" near the appropriate pin on the schematic seems like it wouldn't be a huge burden, and would eliminate any confusion.
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Re: V3.0 pots R52 and R56

Postby billr » Thu Sep 21, 2017 8:46 am

OK, got it, I peeked at some pots I have loose in a drawer; CW has the wiper at term 3.
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