Can someome identify this Raven 4 component?

Discussion in 'Rocketry Electronics and Software' started by Cameron Anderson, Sep 5, 2019.

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  1. Sep 5, 2019 #1

    Cameron Anderson

    Cameron Anderson

    Cameron Anderson

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    Anyone know what this is on the Raven 4 and/or what it does?

    I bought some cheap lipo connectors and the polarity was crossed on some of them so when hooked up power for a wiring test, my e-matches blew and the piece pictured popped clean off the circuit card. I corrected the polarity and got continuity and even reprogrammed the altimeter via my computer and everything looks good.

    I am going to fly it this weekend as a primary altimeter with a known good back-up but i'd sure love to know what that piece is and if it is repairable.
     

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  2. Sep 5, 2019 #2

    OverTheTop

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    Might be a schottky diode, based on meter measurements (low diode drop in one direction). I would have a closer look but I can't find my x10 magnifiers (I have three) anywhere :(.

    One pin connects directly to the V+ terminal. So it could be for reverse polarity protection of the PCA. Two ways it could go, either across the V+ and GND (stops the reverse voltage getting too high on the board) or in series with the V+ so it will block any current from flowing in reverse polarity.
    [EDIT] Just belled out the other connection and it is GND. So the diode is across the V+ and GND terminals to keep the reverse voltage limited somewhat, and likely what took a hit with the reverse polarity.

    If you message Adrian A on this forum he will likely tell you exactly what part it is. Alternatively, and if you like a challenge, use Digikey to find a suitable part.
    www.digikey.com

    Found a magnifier. Marking is CL 687 but I have not been able to identify it yet.
     
    Last edited: Sep 5, 2019
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  3. Sep 5, 2019 #3

    Cameron Anderson

    Cameron Anderson

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    Wow, spot on! I messaged Adrian and he got back to me and said exactly what you said - reverse polarity protection diode.

    I'm still shocked the altimeter works but would love to replace that component if possible.
     
  4. Sep 5, 2019 #4

    OverTheTop

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    Did he say what the part number was? You can purchase one from Digikey or, if you are lucky, he might send you one. He is a very helpful person :).

    If it has a crater in the top then it is likely permanently open circuit. That means the altimeter should be usable, but be extra careful with battery polarity ;). Personally I would get a new part for it. I might even be able to find something here, but I have limited bandwidth lately.
     
  5. Sep 5, 2019 #5

    Cameron Anderson

    Cameron Anderson

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    I asked for a part number or to buy a part from him, still waiting for thr reply. I definitely want the insurance against another slip up
     
  6. Sep 6, 2019 #6

    Adrian A

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  7. Sep 6, 2019 #7

    Cameron Anderson

    Cameron Anderson

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    Part ordered.

    Data looked good on FIP - baro alt was spot on. I've checked continuity on all 4 channels and adjusted their programmed functions a few times to see if the altimeter holds the program and it does.

    I'm testing it in flight on Saturday (with another altimeter as back up) and will report back. I hope it works, and if not, I absolutely won't blame the design (since I was the one who reversed polarity on a clearly marked altimeter) or the help I've received.

    Fingers crossed! (Worst case is I have to buy another Raven in time for BALLS so I hope there is one in stock!)
     
  8. Sep 8, 2019 #8

    Cameron Anderson

    Cameron Anderson

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    Just got back from the field and everything appears nominal (except for landing in a lava rock field and snapping a fin, but that is hardly the fault of any onboard electronics).

    Raven 4, acting as primary altimeter, with drogueless separation at apogee and main at 1,472 functioned as planned.

    Raven 4 reported 4,027 AGL apogee, RRC2 backup reported 4,018 AGL. All Raven-activated e-matches fired and all flight data was captured and saved.

    I know reversing polarity is always a bad thing but the Raven 4 appears to be one rugged unit. Thanks Adrian!
     
  9. Sep 8, 2019 #9

    Adrian A

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    Glad to hear it!
     

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