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D420! How about that?

Discussion in 'Regulators' started by axxel57, Dec 5, 2019.

  1. rsingler

    rsingler Scuba Instructor, Tinkerer in Brass Staff Member ScubaBoard Sponsor

    # of Dives: 500 - 999
    Location: Napa, California
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    I am very sorry that you guys are having issues, but I had a great time diving today with the D420! The seas were four to 6 feet and I blew lunch during the surface interval the motion was so bad down in Key Largo, but the diving was very pleasant. Not Caribbean spectacular, but nice.
    My D420 performed flawlessly. As others have noted, it breathes effortlessly in the standard position and I had no complaints in any of the other positions either. Actually, tuned as light as I had it, it was too light in the standard position, if there can be such a thing.
    We're all waiting for the manual, but reading the recent posts, I would be concerned about any significant depression in that hex key. A new seat and a new knife edge just shouldn't take much pressure to seal. And that jumping from 0.5 inches to 2 inches that Buddha had, is an instability at the knife edge . The old D's used to do that with knife edge flaws, but not a new one.
    My diagnosis is that you are trying to balance a high lever with diaphragm tension against spring counterpressure. That makes for real instability. My lever has a 1/2 mm separation at present, and it used to be even more, but I did raise it a little. But it's still just level with the case rim. Not above the rim. Using spring pressure to counter the desire of the diaphragm to pull in with the faceplate screwed down is not what I think Scubapro would have designed. Use my tip a few posts above, pull the purge lever pin, and make sure you can tap it just a tiny bit.

    I had only one complaint today in the water. Having tuned it to 0.8" (knowing that it was too light), she really wanted to freeflow unless the Venturi lever was placed in pre-dive. I'll retune it tonight to 1.1" for tomorrow's deep dives on the Spiegel Grove. Once I removed the rig from my mouth in water to check my necklace, and even with the mouthpiece turned down she really let loose. This reg really delivers air! I mis-clipped my long hose and lost 500 PSI as it flailed around before I could pull it back in and put my thumb on the mouthpiece. Lol! My bad. Needless to say, I was the one to cut the dive short. Oh, the humiliation in front of my son! Hahaha!
    That's also the last time I'll dive a Miflex long hose, but @tbone1004 could have told me that long ago.

    Hey! I'm sorry for the issues, but I think you should all lower the lever a touch, and screw the hex out all the way. Then walk it in, and progressively raise cracking effort to 1.1-1.3". This is a GREAT reg, and we shouldn't minimize the risks of messing with a center-balanced mechanism without specs or manual.

    Another report in a day or so after some deep tests and a proper cracking effort. 1.3" doesn't mean 1.3" in the water. Closer to 0.3" because of CGF. Perfect.
     
  2. buddhasummer

    buddhasummer Feeling the Love ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
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    I'm going to put mine aside until I get back from Thailand, then I'll overhaul it and start from scratch. Hopefully by that time a manual is out somewhere. Mine is certainly not behaving as it should, delicacy aside. It should hold tune, it's not, it's acting like it's dropped some PCP.

    Interested in your upcoming reports Rob.

    FTR my lever is just shy of top of case rim and there is a fraction of play between the diaphragm and lever, I can hear the tap tap. From what you advise Rob I'm positive my lever is not the culprit. I suspect knife edge or seat, I'll find out in the morning when I pull it apart.
     
  3. buddhasummer

    buddhasummer Feeling the Love ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
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    Oh no, a tool I bought for the D was just delivered and I'm free all day tomorrow...
     
    BenjaminF, rsingler and lexvil like this.
  4. tridacna

    tridacna ScubaBoard Supporter ScubaBoard Supporter

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    Location: New Jersey
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    9A8D7954-5F90-49CF-A2BD-9E0FFB7FA33E.jpeg

    Put these in the pool today. On a MK25EVO. To be honest, I could not tell the difference. The Aqualung mouthpiece was more comfortable on the D400. Looking forward to getting the newbie in the ocean. @buddhasummer the sticker is no problem but I’d like a new one with a hole for a 5mm hex wrench please.
     
    couv and buddhasummer like this.
  5. buddhasummer

    buddhasummer Feeling the Love ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
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    @James79
     
    tridacna likes this.
  6. buddhasummer

    buddhasummer Feeling the Love ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
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    Where's your lever at and where does your hex sit? Trying to gather data. Cheers.
     
  7. Open Ocean Diver

    Open Ocean Diver ScubaBoard Supporter ScubaBoard Supporter

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    Seems odd they would place a sticker over an adjustment screw, wonder if the service kit will come with a fresh sticker?
     
  8. buddhasummer

    buddhasummer Feeling the Love ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
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    It does.

    Guess they don't want you to play with it.
     
  9. axluba

    axluba Barracuda

    # of Dives: 0 - 24
    Location: Germany
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    If you plan on keeping the reg just take off the sticker, punch a hole (hexagonal if possible) in it replace it. :p
     
  10. tridacna

    tridacna ScubaBoard Supporter ScubaBoard Supporter

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    Simon, have you seen a parts kit? I spoke to Dan yesterday at SP. He recommended cracking at 1.2-1.6. (Stock line). I’m at at a hair above 1.1”. Lever at about .5mm below surface. There is no manual yet. It’s in final production.
     
    buddhasummer likes this.

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