Can't find the serial number on a D350/D400

[Tortola]

I'm trying to determine if an old second stage I have is a D350 or a D400. I have looked everywhere for a serial number (even removing the mouthpiece to check the stem), but cannot find one. I acquired this somewhere quite a while ago and it does not have the model number decal on the dive/pre-dive switch.

This is the older version with parallel lines on the purge rather than the grid pattern found later on the D400. From my experience, this was common on D350s and the earlier D400s. (I have owned two D400s with that line pattern). It's matched to an MK10, but I cannot find a serial number on that anywhere.

Any idea where I can find the serial number or otherwise determine which model this is? I do not service my own regs, so I do not have the tools or expertise to open this up. Thanks!

 

[lexvil]

While I don’t recall where the number is, try soaking the purge cover in hot water and pulling it off. Serial numbers don’t really tell you much and the service parts are the same. Have you tried a search on this site?

 

[Tortola]

While I don’t recall where the number is, try soaking the purge cover in hot water and pulling it off. Serial numbers don’t really tell you much and the service parts are the same. Have you tried a search on this site?

Thank you. Yes, I searched on this site and found a lot of good information on the D series, including a range of serial numbers that designate the model. Of course, that requires finding the serial number . From what I can see, al 350s are now serviced with D400 parts. So I guess getting it overhauled will make the question moot.

 

[lexvil]

You may find it under the soft cover.

 

[Kupu]

Did you notice the number at the bottom of the mouthpiece shank as shown in image 2708 on far right?

 

[happy-diver]

 

[Tortola]

Did you notice the number at the bottom of the mouthpiece shank as shown in image 2708 on far right?

Wow, you have great eyes!!! I did not even see that. So, based on what I learned elsewhere on this board, this was manufactured on November 19, 1986, making it a D300 that was later converted to a D400. Thank you very much!