have some red but seems very weak, have replaced all caps on chassis & neck card as they were still original caps from manufacturer. Any help would be greatly appreciated .

You need a CRT analyzer to check the tube, their are some that are pretty cheep on eBay. If you do have a bad red gun it could restore it. Your chassis is probably fine.

Generaly diagnosing a bad crt is not at all difficult. three simple voltage mesurments tell the story . turn the brightness and contrast down so that a raster is just visable. measure the voltage on the red cathode blue cathode green cathode. they should be within a few volts of eac other.depending on brightness and content 123 volt for a dark screen to 60 or 70 volts for a light scree wih bright content. if the voltages dont match and the drives and cutoff are set the same it is an almost cirtinty that the crt is bad.
with this being said a bad crt is sujective evaluation does it work well enough for you.

if uo decide that the cre is bad go to any thrift stoe and pick up a 25 INCH OR WHATEVER YOUR SCREE SIZE IS. for 5 bucks or so. strip the tube out of the plastic carfully leaving all neck comonents intact along with the degausing coil and dag ground. that is the best fix for a bad crt. istructions to handle tube is available on the web. do not hadle wit neck wear safty google an be carfull the crt is a live gernade if strssed.

that being said a tube tester is relic of the past because its reults haave to be iturpeted . rejuvanatinf a rube with it if not done with skill could completly destroy the tube.

rejuvination was a proceedure tha old school techs used to cheat customers out of a few dollrs because it did almost always result in some inprovement and as i stated befor tube performance is subjective the improvement would last long enough to get out of there with his mony