Mk25/A700 making huge noise

[docuw]

Wife and I both bought MK25/A700 last week. Out of water, mine honks like a goose, and hers is silent. Divemaster and the SP tech both say that it is normal for honking. It's on inspiration and still honks with even the lightest of inspiration effort (most regs will honk if you inhale strongly out of water). It breathes great underwater, so I am leaving alone for now.

 

[Zung]

Honking A700 is a fairly well known and documented problem. For those who can read French, there's an article here. It appears there's a new diaphragm that could fix it; it's replaced under warranty during service.

 

[knowone]

Thanks Zung.

My Mk 7 lasted a few breaths and then I swapped to the Air II and then
I pulled out the lump thing inside and now it sits somewhere with another one.

 

[redacted]

Thanks Zung.

My Mk 7 lasted a few breaths and then I swapped to the Air II and then
I pulled out the lump thing inside and now it sits somewhere with another one.

Yes, it is important to realize that when it stops honking, it stops delivering to the primary.

Plus you need to recognize that the honking feature can be a bit unreliable, especially if you are a light breather.

 

[docuw]

There is a fix for the dry, out of water, honking. Jules, and ScubaPro sent the new diaphragm to my LDS. I took both mine and my wife's reg in. They put the new diaphragm in. The new one, is shown in the photo on the right (black) and is actually just a bit thinner/flimsier. The old, clear one, is on the left. Interesting, as I mentioned above, the wife's reg was silent. They opened hers up to do the update, and found that hers already had the updated diaphragm in - hence the reason that we noticed her reg to be quiet! The fix must work.

 

[halocline]

That's a little funny, as I once silenced one of my G250s by putting the clear diaphragm in.

There's obviously some resonance that occurs between the diaphragm and the case, and I suspect is aggravated by less-than-perfect seating between the diaphragm, case, and cover. I'm not talking about a leak, but more like an imbalance of pressure along the edge of the diaphragm.