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Discussion of diving methods and equipment available prior to the development of BCDs beyond the horse collar. This forum is dedicated to the pre-1970 diving.
gene8084
Diver
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Joined: Sun Nov 01, 2009 8:03 pm
First Name: Gene

Voit Trieste II

Fri Jun 23, 2017 2:13 pm

I have a cosmetically very nice Trieste II I just picked up. :D
Unfortunately, although listed as perfect condition it free flows. :cry:

Anyone have suggestions where to look first?
Availability of parts? and specific parts to have on hand and replace if I'm going to crack it open?
Exploded diagram?
Closest diagram I have is the DH R-22 --- how similar/different?

Thanks for your help!
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SeaHuntJerry
Master Diver
Posts: 420
Joined: Sat Jul 02, 2005 12:45 am
Location: Minneapolis

Re: Voit Trieste II

Sun Jun 25, 2017 1:08 pm

Hi Gene,
Possibly Bryan or Greg Barlow :twisted: will rebuild it for you.
Not that difficult!
Jl

swimjim
Master Diver
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Joined: Thu Mar 23, 2006 12:28 am
First Name: Jim
Location: Belgium WI

Re: Voit Trieste II

Sun Jun 25, 2017 2:13 pm

Rare to see one with the label intact. That's a sweet piece. I regret selling mine years ago. I don't remember anything special about going through it. I haven't checked, but I'll bet you can find the manual on this site. Bryan also had the LP diaphragms for it. The Scuba Museum would be another source for parts. If I remember right that used the same HP seat as the Royal and a common LP seat. It also used a standard duckbill. So parts should be easy to come up with.

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Bryan
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Re: Voit Trieste II

Sun Jun 25, 2017 2:59 pm

The Voit Catalogs and Voit service manual are in the Manuals and Catalogs download area.
Doing it right should include some common sense, not just blindly following specs and instructions. .Gary D, AWAP on SB

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Herman
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Location: Raleigh NC

Re: Voit Trieste II

Sun Jun 25, 2017 3:49 pm

It should be the same as other Trieste.
The free flow is either a LP or HP seat or balance chamber oring. No way to tell without at least checking the IP but it doesn't really matter, you should rebuild it completely if you intend to dive it. All the parts are the same as the RAM other than the main diaphragm (which the Scuba Museum has) so rebuilding it is not a problem although the balance chamber oring is a bear to get in/out.
Herman

kworkman
Master Diver
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Joined: Thu Aug 08, 2013 4:17 pm
First Name: Keith
Location: Columbus, OH

Re: Voit Trieste II

Sun Jun 25, 2017 11:14 pm

I thought it was the same internals as the MR12?

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Herman
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Re: Voit Trieste II

Mon Jun 26, 2017 6:37 am

They are the same as the old/original MR-12 and Voit/AMF Titan except for the second stage diaphragm.
Herman

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antique diver
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First Name: Bill
Location: North-Central Texas

Re: Voit Trieste II

Mon Jun 26, 2017 12:34 pm

When you use the new US Divers HP seat, I think you need to change the push pin length! I don't remember what length I trimmed too, but will look in my notes and see if I can find that. Maybe meanwhile someone else will know the proper length and chime in here. ???

Be very careful cleaning the label. Gently hand cleaning with soap and water looks like it should be sufficient on that beautiful specimen!
The paint on that label is prone to come off very easily, so for sure don't put it in an ultrasonic cleaner.

The main shortcoming of that regulator is the shape of the diaphragm... not so much the material, but a new silicone one should help a little. Even that won't make a great breather out of most of these regs. You may also be able to back the second stage out a full turn or maybe even two to reduce the second stage spring tension and then adjust the lever height appropriately.

No matter what I did it just always came back the the arch-shaped diaphragm taking too much effort to get started down. The arch is self-supporting like a bridge archway is made for strength. The best fix i found was to build a diaphragm with different shape, but that is a lot of trouble (and maybe even dangerous). I also tampered with the second stage body's air outlets to get a good boost on the venturi action, but that is really touchy to get where it is not too overwhelming. Mine breaths like a champ even without the venturi alteration, but it took the diaphragm to get a low cracking effort. It will crack lower than is practical to dive with, and would benefit from the new VDH mouthpiece with the deflector to prevent air from wasting out the exhaust on inhalation!

Good find with that beauty!
The older I get the better I was.

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antique diver
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Re: Voit Trieste II

Mon Jun 26, 2017 12:47 pm

About HP seats and Pin Length... I hope that Greg won't mind me quoting him here. Just trying to get the proper info posted for the the proud owner of this Trieste.


Re: Trieste questions
by Bryan » Thu Feb 09, 2012 5:06 pm
Greg Barlow wrote:

If you use an Aqualung HP poppet, you need to cut the pin's length to 0.630".

The Mares Tri-Material HP poppet needs a pin cut to an OAL of 0.645".

If you use the AL version, along with a Voit pin from a unit that contains a balance chamber with the back-up ring, then it should be the correct length of 0.630".

The early Voits without the back-up ring, have a pin that is 0.475" long. It is too short to work with any of the modern HP poppets.

A good rule of thumb is to insert the HP pin into the HP poppet, and then measure its OAL. It needs to be between 0.772-0.780" to operate correctly. Most of the regs that I have serviced fall around 0.775" +-0.002


I believe you should also double check the assembled first stage (without the HP diaphragm installed) to see that you have 1/16th" of activation in the pin movement (with pin pad in place) from fully closed to fully opened hp seat.
The older I get the better I was.

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Herman
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Re: Voit Trieste II

Mon Jun 26, 2017 6:17 pm

There was an official Voit/AMF kit that changed the pin and HP seat to match the USD one. Be sure to check to see if it has already been installed, if so you are good to go.
Herman

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Bryan
Plank Owner
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First Name: Bryan
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Re: Voit Trieste II

Mon Jun 26, 2017 10:04 pm

You can trim a Conshelf pin to length if needed.
Doing it right should include some common sense, not just blindly following specs and instructions. .Gary D, AWAP on SB

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Bronze06
Master Diver
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Joined: Tue Jul 01, 2014 5:33 am
First Name: Russell
Location: Tabuk, Saudi Arabia

Re: Voit Trieste II

Sun Jul 09, 2017 2:58 am

I have done the Conshelf pin trim thing and have also found a couple of regs (MR-12s, Triestes and Titans) that already had the AMF/Voit to USDseat conversion done to them. I disagree with some divers saying that the Trieste regulators don't breath well as configured. I have three of them, put new repro silicon 2nd stage main diaphragms from Rob at the Scuba Museum, and all breath great. The key is getting that new silicon 2nd stage main diaphragm in for better breathing effort. Just tweak the IP (135) and for me, hair trigger the 2nd stage lever a bit and they breathe like any modern single hose IMO.
I've heard and I am tired of the whining argument about "But its 2nd stage main diaphragm is too small, wah, wah, wah etc. ad nauseaum". When you think about it, the 2nd stage diaphragm is not any smaller (by much) than the Titan II single hose 2nd stage. That Blue label is a keeper, by the way.
The MR-12 is a good source for possible 1st stage parts replacements if your HP orifice is kaputt in your Trieste.
"Where'd ya get that ol' thang, don't cha' know them thare things ill kill ya!"

Live From the Red Sea,

Russ

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