ScubaPro mk2 honking noise.

[HM_legon]

Hello SB,

I've had a not so pleasant series of experiences with a shop near my college.

They serviced my ScubaPro MK2, w/ R380 and usd micra, and gave it back to me honking like an accordion.

I took it back to get it fixed, they gave it back claiming it fixed but it makes the same noise and a hose was half unthreaded from the reg!

Anyway, I'm back in Austin now, and I'm in no hurry to give them by reg back.

I know it originates in the first stage, as it makes the sound when I use either regs or the bcd inflator.

Any ideas on how to fix it myself?

Thanks,
Legon

 

[davehicks]

Hello SB,

I've had a not so pleasant series of experiences with a shop near my college.

They serviced my ScubaPro MK2, w/ R380 and usd micra, and gave it back to me honking like an accordion.

I took it back to get it fixed, they gave it back claiming it fixed but it makes the same noise and a hose was half unthreaded from the reg!

Anyway, I'm back in Austin now, and I'm in no hurry to give them by reg back.

I know it originates in the first stage, as it makes the sound when I use either regs or the bcd inflator.

Any ideas on how to fix it myself?

Thanks,
Legon

It needs to be taken apart again and lubricated better. The piston in likely vibrating and causing the noise. If you don't have the tools or experience to do this, bring it to somebody else.

There are manuals and YouTube videos that can show you how if you want to do it yourself.

Did they use a service kit and return the old parts as evidence they did the work?

 

[HM_legon]

It needs to be taken apart again and lubricated better. The piston in likely vibrating and causing the noise. If you don't have the tools or experience to do this, bring it to somebody else.

There are manuals and YouTube videos that can show you how if you want to do it yourself.

Did they use a service kit and return the old parts as evidence they did the work?

They didn't give anything like that back, I've got an non insignificant amount of experience with vintage double hose and old usd conshelf first and second stages.

I've got silicone grease and plenty of wrenches and what not. I think I'm decently equipped enough to take a Crack at relubrication. I'll check out YouTube to see what knowledge can be gained from there.

Thanks for the info!

 

[Tanks A Lot]

Borrowing from a previous response:

Whistling on a first stage usually comes from two sources:

• On first stages of all types, from harmonic resonance between the bias spring and other first stage components. To get rid of this harmonic resonance, the following are suggested by almost all manufacturers, in this order: Flip the spring around; Rotate the piston; Exchange the spring; Exchange the piston (Flow through only).
• On Flow-through piston regulators, air flowing past the seat into the piston bore. Historically, manufacturers have used a cone shaped seat to mitigate this. As a user or technician not much can be done if a poorly engineered seat is used.

As your Scuba MK2 is a piston first stage, but not a flow through piston, the obvious culprit will be the bias spring.

From the attached schematics, look for spring 01.020.226. I'm not sure if you have a MK2, MK2+ or MK2 EVO. Regardless, they all look more or less the same.

1. Unscrew the End Cap #10.103.109.
2. Then do one of the following starting from the first: Flip the spring around; Rotate the piston; Exchange the spring
3. Assemble the unit and test.
4. If the problem persists, move on to the next item from bullet point #2, otherwise be a happy chap.

The only specialized tool you need for this is a C-Spanner. The end cap should have been tightened very little and no vice tool or similar should be necessary for this job.

I have seen whistling not from the main bias spring, but the spring on ScubaPro DIN regulators which surrounds the filter. This has been very rare in my experience and usually was a very slight, subtle whistle. Something similar can occur on diaphragm first stages with the spring that holds the poppet.
The spring on the DIN systems would be 01.020.700. The exact same from the above bullet points apply to this spring. However, the main bias spring is the cause in most cases.

I would be very much surprised if this had anything to do with lubrication.

 

[boat sju]

IDK but mine does the same thing at full HP tank pressure. Quiets down probably at less than 3000 psi. I don't worry about it but I don't dive that regulator very deep anyway.

Edit. Mine is what you might call a "vintage" Mark 2.

 

[HM_legon]

IDK but mine does the same thing at full HP tank pressure. Quiets down probably at less than 3000 psi. I don't worry about it but I don't dive that regulator very deep anyway.

Edit. Mine is what you might call a "vintage" Mark 2.

Ive had a similarly experience, as I dive the reg, the water pressure and tank pressure have a direct impact on the sound. When the tank is lower and I'm under about 15 feet of water, the noise is gone completely.

I'll go through the steps provided by tanks alot and update y'all at a later date.

Thanks for the input