Modifying the balance chamber on a TX50

[reefrat]

I live in Australia and have just ordered an Apeks TX50 second stage from the UK. Apparently the European (CE) version of this reg dosen't breathe as well as the U.S. version because of a small plastic extension on the balance chamber.

The effect of the this small protruberance is to limit the amount that the inhalation resistance can be decreased in order to help prevent freeflows in very cold water.

This allows the reg to achieve CE approval in Europe but is pointless here in Oz.

I have read in some posts that it's common practise to dismantle the valve and remove 2 or 3 mm from the balance chamber to restore the reg to it's full easy breathing potential.

I've downloaded the TX50 (Seaquest) service manual from the web and can't see any problem with doing the above..except that I won't be able to replace any O rings with new ones because Apeks won't supply service parts to individuals!

Question: Has anyone done this mod to an Apeks TX reg? And if I'm careful with the O rings can I put the existing ones back in when I reassemble it?

It should be obvious I'm not a trained technician and have not previously serviced regs but it looks fairly straightforward.

NB: I also emailed Apeks to see if they would supply the US spec part but haven't heard back yet.

 

[LUBOLD8431]

You shouldnt have to remove any orings to make this mod. Just be careful...

 

[TechBlue]

I think they now ship the same "CE" spec part to the US so I wouldn't wait on that

 

[brian cooper]

Hi reefrat,
The facts:- you can mod the chamber, long type=22.5mm, short type 20.2mm.
without pulling chamber from shuttle valve it can be sanded down in length(so as not to disturb the o-ring) but I've never seen a worn chamber/o-ring.
The mod just reduces the spring compression, independant of the knurled adjuster position.If you get the cracking pressure down to a minimum in air when you submerge and go diaphragm down then the extra water pressure can cause the reg to weep so you have to turn the knurled adjuster in a turn or so to stop it starting to free flow(This was mensioned late last year on another thread).
Do not go shorter than the 20.2mm otherwise the O-ring could disengage when the knurled adjuster is fully out.

I've not had problems with my modified T50D(very early model)and have it set at 9.6bar IP, Cracking pressure 20mm with the knurled adj fully out, if fully in the cracking pressure goes up to 50mm. With the venturi on plus I can still get all the air I want

Brian C

 

[reefrat]

Thanks all for the information, I now feel confident that if I take my time and follow the manual I should be able to modify the chamber to about 20.5 mm without disturbing the O rings too much.

Incidentally, I phoned two service technicians at major dive shops here about this before writing the post. One had no idea what I was talking about but indicated he wouldn't modify factory parts anyway...and the other simply refused to comment!!

I am sure I would have got a different and more helpful response only a few years ago but now everyone is so wary of litigation!