I joined the forums about a week ago in hopes of getting help with my RPT's failing video. Rather than just jumping in with questions, I decided to use the search feature to compare similar questions and solutions.
Over several years the set started loosing color, becoming blurry and darkening. Blue halos formed around brighter objects. Eventually blues were gone, followed by a loss of greens. Basically the set became a giant monochrome monitor.
After reading several post on tube failures and fluid issues, I went to work. I opened up the set - WOW was it FILTHY - and began the task. First thing was to carefully vacuum away the mountain of dust/ dirt that had built up. This was the second cleaning and much needed process.
Next I powered the RPT to examine the tubes. All three lit up and seemed to have an approximate equal amount of light projecting. Then I looked directly into each tube.
Red: some flecks of small trash - clear imaging
Green: same trash - visible but blurred (hazy) image.
Blue: trash specs - 90% opaque - shadow movements only.
I ordered replacement fluid from Mat Electronics($18), downloaded the service manual and parts list($8) and picked up a turkey baster and plastic tray.($3)
Yesterday I took my took my time, following directions from the manual, post by MOtvGuy and others, I pulled one crt at a time, removed old fluid, cleaned, re-assembled and re-installed. I left the red crt lone for now.
The blue crt was completely crusted with a brownish growth. Both blue and green fluids were dark and opaque.
The lens' did not clean as well as I'd have wanted, even with a good soaking in CLR and cleaning with Alcohol. Obviously they have been to long over due for for service.
However - WOW WOW WOW - after setting convergence through user menu, the picture looks better than it ever did. Bought from sears in '98 and had (3) non-satisfactory service calls about picture quality during warranty.
Being comfortable with any mechanical work, but lacking any technical knowledge for this job, ALL I can say is:
THANK YOU ALL for your post and shared insight!!!!!
P.S.- Next - Solving the ever present brightness issue.