SP Mk19 Whistling

[Mike Walker]

I've read the other couple threads on reg whistling and they get me in the ballpark but figured I'd post to see if anyone had any more specfiic thoughts on this:

2 reg sets (Mk19 + G260) - sidemount pair. (EDIT: MK19EVO DIN)
Both new in spring - identical dive history.
Factory setup - have not been serviced.
30 dives in cold water, no issues.
Now diving in warm water and the whistle has appeaed.
Whistle only happens deeper than ~25m and is quite consistent. Once I'm back above ~25m it stops.
Both sets of regs do this. Seems to be 1st stage as BCD inflate also causes whistle.
They both breath just fine.

It'll be a couple months and a bunch more dives before I'm in the vicinity of the selling shop for warranty work.
Wondering if anyone has any short term thoughts on a root cause. If for no other reason than to satisfy my curiosity.

 

[davehicks]

The Mk25 is famous for squealing if the Piston and bushing are not lubricated enough. The Mk19 is a diaphragm design, so not the same. Still, it could be the solution is similar. Have the reg serviced, maybe it does not need a parts kit, but clean and lubricate everything. The fact that both are doing the same thing might indicate that they were both not assembled correctly in the first place.

 

[grantctobin]

Unfortunately, seems to happen with MK19 more than others, though I’ve had some 25s with the same issue.

You can do a full service, insert a new parts kit, and have squeaking. Insert a different new parts kit, and have no squealing, or vice versa. Helium makes it worse.

 

[rsingler]

MK19EVO DIN or Yoke?

 

[Mike Walker]

MK19EVO DIN or Yoke?

MK19EVO DIN

Unfortunately, seems to happen with MK19 more than others, though I’ve had some 25s with the same issue.

You can do a full service, insert a new parts kit, and have squeaking. Insert a different new parts kit, and have no squealing, or vice versa. Helium makes it worse.

Interesting... well, at least it might be a known issue...

 

[Sevenrider860]

I have seen this with the MK11 also. On one of them, rather than a full service and parts replacement, I added lube to the balance chamber and shaft of the HP Valve. I don't know if it was the lubricant or simply repositioning of the valve components that stopped the whistle.

 

[Nemrod]

MK19EVO DIN


Interesting... well, at least it might be a known issue...

It is a (?) known issue with some piston regs that do not like the piston shaft under lubricated and there is a little more to it than just that. However, the Mark 17/19 Evo have nothing in common with a Mark 25 series regulator. Unless it is intrinsic to the turret and the description does not seem to lead that direction.

 

[rsingler]

It's why I asked about DIN vs yoke. Of all the myriad things Scubapro has wrestled with trying to fix this issue (lube, rotating the HP seat, etc.), the one thing the DIN Mk19EVO shares with the Mk25 is a thin, low pressure spring in the high flow tank air pathway. In the Mk25, there's some sort of harmonic vibration going at certain air densities or conditions.
And indeed working on the spring been my most consistent fix for Mk25 whistling. In the Mk25, I take it and overtorque the ends so that it now has a very faint banana shape. That asymmetry still holds the oring stack in place, but now the side of the spring touches the bore, instead of vibrating in the breeze. I've had good luck.
The DIN Mk19EVO filter spring is a little smaller and a little more compressed, so I don't think that's what's going on. But it's easy enough that you might try that, and see what happens.
I don't think that's the issue, however. It's probably poppet vibration at certain depths (higher absolute IP). You might try removing the HP seat carrier and rotating the poppet or replacing it. But don't banana  that spring. It's critical to have no friction affecting poppet movement.

 

[Mike Walker]

It's why I asked about DIN vs yoke. Of all the myriad things Scubapro has wrestled with trying to fix this issue (lube, rotating the HP seat, etc.), the one thing the DIN Mk19EVO shares with the Mk25 is a thin, low pressure spring in the high flow tank air pathway. In the Mk25, there's some sort of harmonic vibration going at certain air densities or conditions.
And indeed working on the spring been my most consistent fix for Mk25 whistling. In the Mk25, I take it and overtorque the ends so that it now has a very faint banana shape. That asymmetry still holds the oring stack in place, but now the side of the spring touches the bore, instead of vibrating in the breeze. I've had good luck.
The DIN Mk19EVO filter spring is a little smaller and a little more compressed, so I don't think that's what's going on. But it's easy enough that you might try that, and see what happens.
I don't think that's the issue, however. It's probably poppet vibration at certain depths (higher absolute IP). You might try removing the HP seat carrier and rotating the poppet or replacing it. But don't banana  that spring. It's critical to have no friction affecting poppet movement.

That's very useful - thanks.
When I send it in I'll probably forward this thread.

 

[stepfen]

One of my Mk11's whistles too... It does so during the deepest part of the dive (high tank and ambient pressures) and slowly disappears as tank pressure and/or depth decrease. A fellow diver mentioned that she could hear it during a Raja Ampat trip back in January. It doesn't really bother me - in fact I kind of liked it. One less diver near me