MK5 - or something?

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qwertz

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Scuba Instructor
Messages
27
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Location
Germany
# of dives
200 - 499
Hi Pals,

got into reg repairs and went to ebay to acquire some skill-honing objects.

The attached picture was advertised as MK10, but I decided it is an MK5 due to the conical shape of the IP body. 10€ further down the road, I had a service kit and started disassembly.

There is no corrosion, no excessive damage whatsoever, all O-Rings were lubed quite nicely - just a few scratches here and there. The attached pictures show some around the piston head area (IP chamber <> piston head o-ring), that I tried to polish, using 2400 grit sandpaper.
The knife-edge looks sharp af under my cheap usb-microscope, so no polishing on that side.

Before I assemble it, I would like to check with the gurus on this board two things
1.) Anything you can see in the pictures that makes this 1st-stage dangerous? I tried to figure if there are parts that absolutely need to be replaced according to SP, besides the O-Rings within the service kit, I threw away all O-Rings. New HP-seat - thats about it (old one was blue).
2.) All the schematics available to me displaying a MK5 look different. In particular: Those 3 rods, inserted into the body to press down the ring holding the spring in place. That thing I cannot find in the schematics as well.
3.) I tried to scratch the turret bolt with a SS pick, to no avail - so I assume it is SS aswell, which is the only thing I should be replacing, according to my research.

Any clues what kind of 1st that is? I figured there were at least 4 different MK5 versions, but I seem to be unable to differentiate those - besides that none, imho, use that big spring-holding ring, which should be an exchangeable shim from what I understand.

Cheers for your help!

Sam

20220513_081710.jpg
 

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I don't know who made that reg. But Cressi uses that 3 rod setup in several of their piston regs and I'm pretty sure they once made a MK5 clone. For example this is a disassembled AC2:
305_data_detalles_720_despiece_ac2_vertical.jpg
 
It actually never occurred to me, that it might be a different manufacturer ... duh ...
Had a closer look, there is absolutely nothing on any piece of that 1st stage. If it was a SP, there should be a Serial-#, shouldn't there?
 
Hi Pals,

got into reg repairs and went to ebay to acquire some skill-honing objects.

The attached picture was advertised as MK10, but I decided it is an MK5 due to the conical shape of the IP body. 10€ further down the road, I had a service kit and started disassembly.

There is no corrosion, no excessive damage whatsoever, all O-Rings were lubed quite nicely - just a few scratches here and there. The attached pictures show some around the piston head area (IP chamber <> piston head o-ring), that I tried to polish, using 2400 grit sandpaper.
The knife-edge looks sharp af under my cheap usb-microscope, so no polishing on that side.

Before I assemble it, I would like to check with the gurus on this board two things
1.) Anything you can see in the pictures that makes this 1st-stage dangerous? I tried to figure if there are parts that absolutely need to be replaced according to SP, besides the O-Rings within the service kit, I threw away all O-Rings. New HP-seat - thats about it (old one was blue).
2.) All the schematics available to me displaying a MK5 look different. In particular: Those 3 rods, inserted into the body to press down the ring holding the spring in place. That thing I cannot find in the schematics as well.
3.) I tried to scratch the turret bolt with a SS pick, to no avail - so I assume it is SS aswell, which is the only thing I should be replacing, according to my research.

Any clues what kind of 1st that is? I figured there were at least 4 different MK5 versions, but I seem to be unable to differentiate those - besides that none, imho, use that big spring-holding ring, which should be an exchangeable shim from what I understand.

Cheers for your help!

Sam

View attachment 722331
This is a Cressi, not a Scubapro!
You can tune IP externally, even with the reg pressurized.
Here the drawing of it, a version slightly more modern than your, but basically the same:
cressi-spina-regolatore-di-primo-stadio-hp-7-16.jpg
 
As others have said, it isn't a ScubaPro.

Question - did you test it before taking it apart to see if there were issues or what it was behaving like?
 
Congrats!
My favorite MK5 Clones, I should have two or three of them (one with Environmental Cap).
Really cool that you can adjust so easy the IP with the cap without handling with shims.
I would trade it instantly for one of my DIN MK5s if you like.
Still couldn't find out the exact name of those Cressis. Does somebody know?
Angelo?
BTW, the MK5s never had a S/N.
The first S/Ns stamped into the body were those of the 2nd generation of the MK10s.
 
The F3 didn't have those rods as you can see in the schematic found on the linked post. Perhaps it's possible they could have fitted as an update?

 
The F3 didn't have those rods as you can see in the schematic found on the linked post. Perhaps it's possible they could have fitted as an update?

Actually Galaxy designates the second stage:
cressi3243c-2_small.jpg

This was sold coupled either with the unbalanced "MK2" clone:
CRESSI%20SUB%20F2%20Galaxie.jpg

Or with the balanced "MK5" clone, which is the one of the OP:
CRESSI%20SUB%20F3%20Galaxie.jpg

the unbalanced version was called Galaxy F2 (introduced in 1985):
whilst the balanced version was called Galaxy F3 (introduced in 1987):
 

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