What is 56pt convergence? (1 Viewer)

[Lennart]

I am a newbie and just got a new 50hx81. I read a lot about making the 9pt and 56pt convergence. But, I have very little idea what convergence is. Can someone please help? I tried other forum and no one reply. Hopefully, someone here will help me out! Thanks in advance!!!
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Len

 

[Allan Jayne]

For an RPTV, convergence (also called registration) is the getting of the red, green, and blue sub-images from the respective little CRT's down below to coincide. Otherwise a white lines looks like side by side red, green, and blue lines and objects have colored fringes, not what you call a sharp picture.
THe 9 point method allows you to line it up in nine selected spots on the screen (one in the middle, one near each corner, one near top center, etc.) and hopefully it doesn't have much of an error in between the 9 points.
The 56 point method is probably buried in the service menu and has 56 different points (probably in a 7 x 8 grid) where you line things up. SInce the distance between the points is less, there is less opportunity for an error to be large in between. But then having to make 56 adjustments is more time consuming, especially when making one adjustment often throws off the adjustments of nearby points and you have to go back several times to redo each point.
More video hints: http://members.aol.com/ajaynejr/video.htm
[Edited last by Allan Jayne on October 08, 2001 at 02:46 PM]

 

[Lennart]

Cool! Thanks Allen for the Precise and Clear explanation! I am going to get the set tomorrow. From what I see in www.keohi.com I should wait a couple of weeks before doing serious convergence tweaking. Hopefully, by the time, I find out exactly how to do it on my set. Thank you!!!
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Len