[R-390] An update - R390A Cosmos disassembly question

[jrfke5ri at aol.com]

Indicating Silica Gel
Indicating silica gel is a silica gel bead or granule that has been washed with a concentration of cobalt chloride ( a heavy metal salt). The cobalt chloride is a deep blue color when it is dry and turns from blue to purple to pink as it becomes saturated with moisture.


KE5RI





-----Original Message-----
From: wa3frp at aol.com
To: r-390 at mailman.qth.net
Sent: Thu, Apr 15, 2010 7:25 am
Subject: [R-390] An update - R390A Cosmos disassembly question



Thanks to everyone for their feedback.  Now inside.  It was quick work once I 
knew that the final chamber was held by a rubber gasket and not screwed into 
place.  Happy to report that the interior is pristine.  The valve stem appears 
to have a manufacturing defect so it's very doubtful that this PTO was 
pressurized for longer than a few minutes. The 
two dessicant capsules are still tied in place and are blue. I'm not sure from a 
quick scan of the documentation if blue is good or bad. 
 


-----Original Message-----
From: Roy Morgan <k1lky at earthlink.net>
To: wa3frp at aol.com
Cc: r-390 at mailman.qth.net
Sent: Wed, Apr 14, 2010 10:41 pm
Subject: Re: [R-390] R390A Cosmos disassembly question and a second question 
too!


On Apr 14, 2010, at 10:25 PM, wa3frp at aol.com wrote:... 
> Now, I'm working to open my Cosmos PTO ... I can't figure out of the > final 
metal chamber is just stuck or is a tight fit or is possibly a > screw on. 
 
Russ, 
 
Likely it's just stuck. There is an O-ring that the can slides over at the last 
quarter inch of travel as it's installed. Llikely the O-ring is stuck. I suggest 
you slip a modestly small thin screwdriver under the lip of the can and pry - do 
this at a number of places and the thing may well loosen up and come off. A tiny 
bit of wax or sillicone grease might be right as you re-assemble. 
 
> ... pressurized with 15 pounds of dry nitrogen. (This was on the > warning 
label). The nitrogen has long since dissipated but I'd like > to know if others 
have repressurized after assembly or not. 
 
I've never heard of anyone putting pressurized nitrogen in there, or even 
unpressurized nitrogen. I suggest you ignore the pressure and the nitrogen 
altogether. You may well find some dessicant capsules in there. These can be 
dried out in a 200 degree oven for an hour or so and re-installed if you like. 
 
Roy 
 
Roy Morgan 
k1lky at earthlink.net 
529 Cobb St. 
Groton NY, 13073 
Home: 607-898-3607 
Cell: 301-928-7794 
 
 

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