I grabbed this tidbit off thedecostop. From my reading of the discussion I'd say it's possible that over-tightening the yoke retainer during 1st stage reassembly could explain some of the cracks.
R..
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NOAA DIVER ALERT
This is an important Diver Alert issued by the NOAA Dive Center, Seattle, WA.
There is a potential problem with MK-20 first stage regulators manufactured by
SCUBAPRO.
Cracks have been found in three MK-20 first stage regulators that were issued to NOAA divers. These cracks seem to happen over time and do not appear to be a sudden event. One of the cracks was found by a diver during diving operations prior to his dive and the other two were discovered during annual service here at the Dive Center. These cracks are similar nature and are located in the body of the 1st stage regulator where the scuba yoke assembly attaches to the 1st stage. (reference pictures below). The crack is on the high pressure side of the regulator and may result in a catastrophic failure of the regulator.
To check for this potential crack, remove the decorative plastic cap at the base of the first stage. This can be done, in most cases without tools by twisting and pulling on the cap. This inspection is to be done at the beginning of each diving day.
If, after inspection, you suspect a crack in your SCUBAPRO MK-20 first stage,
DO NOT DIVE THE REGULATOR!
R..
---------------------------------
NOAA DIVER ALERT
This is an important Diver Alert issued by the NOAA Dive Center, Seattle, WA.
There is a potential problem with MK-20 first stage regulators manufactured by
SCUBAPRO.
Cracks have been found in three MK-20 first stage regulators that were issued to NOAA divers. These cracks seem to happen over time and do not appear to be a sudden event. One of the cracks was found by a diver during diving operations prior to his dive and the other two were discovered during annual service here at the Dive Center. These cracks are similar nature and are located in the body of the 1st stage regulator where the scuba yoke assembly attaches to the 1st stage. (reference pictures below). The crack is on the high pressure side of the regulator and may result in a catastrophic failure of the regulator.
To check for this potential crack, remove the decorative plastic cap at the base of the first stage. This can be done, in most cases without tools by twisting and pulling on the cap. This inspection is to be done at the beginning of each diving day.
If, after inspection, you suspect a crack in your SCUBAPRO MK-20 first stage,
DO NOT DIVE THE REGULATOR!
