got this about a month ago, lousy picture, check the CRT weak green gun, did an auto restore with a CR-70, it responded very well cut off and emissions came right up to the other guns. Still lousy greens. put on a vectorscope with color bars, NO green. the pattern on the scope looked terrible. I let is set for a while not sure where to with it. finally decided to try adj some of the coils in the chroma circuit. Hooked up the vectorscope again, the pattern was like a single slanted line and not the circular pattern it was supposed to be. tweaking up one of the coils caused the slanted line to open up to an elipse, a bit more and it came up with the circle patter, YEA!! now I could see the red/blue and green bars, before I could see red and blue but nothing on the green. I fooled with the adjustments some more got get the pattern as correct as I could, and not the color is really quite good.

If you are going to work on color TV's I think a vectorscope is a worthwhile investment, I got mine for 10$ IIRC of ebay. I just needed the IC's to be reseated and some PS caps (a heathkit).

I think I will be using this on all my color sets to check out and tune up the chroma section. I have some sets that tended to have brown grass (same as the porta color) so they may benefit from a slight touch up.

I think you have another problem. If there was no green drive at all then tweaking coils should not have corrected the problem; you might have bad connections somewhere.

it works fine now. the green chroma just did not work. I had Blue and Red, solid green came out as solid blue.

for you porta color owners the offending coil was A16 its the top slug of the coil, mounted pretty much right under the crt (HC models). The best way to get at it is from the bottom with a diddle stick that lets you pass thru the bottom slug.

the real key to success was with the vectorscope, let me dial the coil in for the best symmetry of the display on the scope of the keyed color bars. I find this a bit easier than looking at one chroma drive at a time on a regular scope.

I owned one of the first ones. The green channel will never be comparable to anything today, because it was matrixed to the luminance channel which was not DC restored.

good to know, but the point of this thread was IF your porta color is not producing ANY green, like gray grass that should be green or deep green that comes out blue, and the tint control does not correct it then it may be a problem with the tuning of the coil that I am mentioning.

the model I I have is the 1966 HC. tweaking that on coil made if go from a set that would produce Red and Blue hue to a set that would make red, blue AND green hues, True its a grainy pic with the large shadow mask holes but that simple tweak made all the difference.

Again it really helped checking it with the vectorscope, gives you a quick check of all 3 drives.

Did not realize I had a thread on this set already so I am linking to the orig thread

viewtopic.php?f=3&t=189400&p=1596800#p1596800

Sorry, but, forum rules are against two of the same post. Since the other one has the most replies, I will simply lock this one.
Bill Cahill