That coolant forms the primary lens on ALL
CRT RPTVs I have ever seen, and on the type designed for that in the ceiling pj realm as well. The Dwins had an air gap and I have seen that also on the Sonys, but rarely. Usually they design that coolant to be up against the CRT face to assist in keeping those faces cool, since they get quite a workout. Without that coolant they would overheat much more readily than with.
Since that gives them the opportunity to form a lens, they take it. Comes out like in my high school chemistry class, where we added oil between the slide and the lens of the microscope, and the optical characteristics changed accordingly.
You don't need to remove that gun to replace the coolant, but that might be easier than tilting the entire machine appropriately, like I did once when a Panasonic CRT RPTV needed the same treatment, for exactly the same reason. We used 2x4s to prop it up at the proper angle - straight up on the affected gun - before I went in and removed the coolant cover lens to replace that coolant, watching very carefully for the top air bubble. Ideally there's no air bubble in there at all, edges of which can reflect back the light from inside the chamber.
In the future you might want to consider paying me for 2 minutes of my time before you embark upon a journey you may not need to be taking. That's all the time it woulda taken to warn you off on all of this and into the correct direction. The deeper optics cleaning NEVER
involves removing that lens and dealing with that coolant! No optics cleaning involves that. Cooties in the coolant yes, optics cleaning no.
The kind of time one loses by insisting on recreating the wheel himself rather than learning from someone else who has already been there - it's just uncountable, in hours. When you have a family or a highly paid profession that takes up all your time, you just don't have that kind of risk time available.
If you continue and proceed to break the neck off the red tube before you're thru, rack up a few more hours plus expenses plus setup from scratch on a new gun.
Most people don't have that kind of time on their hands. Congrats David, I know you'll pull thru OK, you're emminently/incredibly tenacious, I get that, and my kudos to you.
But I would not
recommend your avenues of approach for most of the readers here. Owners, please let David's adventure here be a lesson to us all, and not an example of the ideal approach!
Try learning from someone else's mistakes. I am a fan and long term follower of multi-millionaire Marshall Sylver, and that would be one of his first advices: learn from the mistakes of others. It's much more cost effective in terms of your valuable, irreplaceable time than starting from scratch and making 20 years of mistakes just to catch up!
Check out Marshall on Facebook if you're curious, and contact me directly if you want to know more. I'll get you in -