BA156

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One thing first; there are (I believe) two different 108 diaphragms. One of these absolutely does not fit the 109, the geometry of the case and lever is very different. I know this because at least one of my 108s has this diaphragm, and it's obvious that it would not work in a 109. So you must have the other.

Second thing; the 109 diaphragm should be thin black silicone, although I guess there were some blue and some orange ones as well. I have freely substituted diaphragms between the 109, G250, and R190. That part is 11300008. There was an earlier diaphragm assembly; it appears that the plastic disc was removable. That assembly, which is in the B/A schematics, 11109011. It seems that there have been a few variations and part numbers, but they all should work fine. I have never seen a neoprene or otherwise 'thick' diaphragm on a 109 or balanced/adjustable.

What happened with mine is that the diaphragm stuck to the purge cover, presumably from some minerals in the water when it dried. The last several dive trips I've taken were all in Mexican caves, where the water has a really high mineral count. So it was just a matter of taking the purge cover off, diaphragm off, rinsing and drying each, and putting it back together. I hope your issue is as easy to fix.

Mine didn't feel sticky; I wonder if yours is degrading. I've had tents that were siliconed-nylon do that, and they feel sticky. Unfortunately that's the end for the tent when it happens.
 
One thing first; there are (I believe) two different 108 diaphragms. One of these absolutely does not fit the 109, the geometry of the case and lever is very different. I know this because at least one of my 108s has this diaphragm, and it's obvious that it would not work in a 109. So you must have the other.

Second thing; the 109 diaphragm should be thin black silicone, although I guess there were some blue and some orange ones as well. I have freely substituted diaphragms between the 109, G250, and R190. That part is 11300008. There was an earlier diaphragm assembly; it appears that the plastic disc was removable. That assembly, which is in the B/A schematics, 11109011. It seems that there have been a few variations and part numbers, but they all should work fine. I have never seen a neoprene or otherwise 'thick' diaphragm on a 109 or balanced/adjustable.

What happened with mine is that the diaphragm stuck to the purge cover, presumably from some minerals in the water when it dried. The last several dive trips I've taken were all in Mexican caves, where the water has a really high mineral count. So it was just a matter of taking the purge cover off, diaphragm off, rinsing and drying each, and putting it back together. I hope your issue is as easy to fix.

Mine didn't feel sticky; I wonder if yours is degrading. I've had tents that were siliconed-nylon do that, and they feel sticky. Unfortunately that's the end for the tent when it happens.
Both diaphragms have a part # 11-109-124, I don’t know if one is actually thicker it just feels that way, maybe because one feels slipperier than the other also and more supple. Going to try the 109 in the pool tonight will see how well it breaths underwater in 15 feet of water. :)
 
https://www.shearwater.com/products/perdix-ai/

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