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Path: news.uiowa.edu!hobbes.physics.uiowa.edu!newsrelay.iastate.edu!vixen.cso.uiuc.edu!howland.reston.ans.net!gatech!udel!news.mathworks.com!uunet!in1.uu.net!newsflash.concordia.ca!vax2.concordia.ca!spector From: spector@vax2.concordia.ca (Mitchell Spector) Newsgroups: comp.sys.apple2 Subject: Re: GS RGB internal adjustments Date: 13 Apr 1995 21:38 -0500 Organization: Concordia University Lines: 110 Distribution: world Message-ID: <13APR199521384183@vax2.concordia.ca> References: <3m5clp$pvc@mark.ucdavis.edu> <3m6g88$sef@gap.cco.caltech.edu> <3m7u2p$je8@mark.ucdavis.edu> NNTP-Posting-Host: vax2.concordia.ca News-Software: VAX/VMS VNEWS 1.50 In article eddy@cs.ucdavis.edu (Alexander H Eddy) writes... > >Opening up the case, I find the following pots: I've opened three of my AppleColor RGB monitors, two of which I've performed internal adjustments on with it live (power on). It's certainly very risky and indeed life threaten if your not careful, so I don't recommend opening it with the power on _or_ off if your not experienced or don't have lots of patience and a steady hand. >V-lin >H-cent >V pos1 >V pos2 I assume these controls are on the neck of the CRT. Most likely they control Vertical and Horizontal positioning of the light guns, but this is only a guess. >Focus I've not used this control, but apparently it does just that. Corrects the screen focus if it's blurred or the image is distorted. The first two or so lines of my current RGB has a bit of a focus problem (there's a bit of blue and red fringe on either side of text characters if you look very closely) but I'm uncertain whether "FOCUS" would fix this. Most likely you'd want to adjust it if your entire screen has such a problem. >Screen This is the master brightness control. As screens age, the screen gets darker eventually forcing you to turn up your brightness control more and more for an acceptable display. Eventually turning it all the way up won't help, so you'll need to increase the master brightness (I had this with one of my screens). Sometimes the brightness will increase slightly with age, so you'll have to decrease the master control (I did just that with this screen I'm typing on now). >sub cont The master contrast control. Just like brightness, the constrast will sometimes decrease with age (I find this condition rare, but with one of my screens I needed to increase it). >G cut off >R cut off >B cut off I'm not 100% sure, but I've been told these control the point which which the Red/Green/Blue colors become black (0% color). You may find playing with these help get the proper tint, with two of my screens I had to adjust either the R-G-B cut offs. >R drive >B drive These control the voltage of the Red and Blue guns. Turning these will either increase or decrease the amounts of blue or red in your picture. >(no, didn't see a G drive) >....so, anyone have detailed descriptions of what all these do? There is no G-Drive, apparently Green is the standard on which Red and Blue balance between. You can of course use the G-cut-off to adjust greens, as I found. >I assume H cent will fix my particular problem. Also, I find that my >"white" is distinctly on the yellow side of white. Logically, increasing >the percentage of blue in the picture would correct this, but >should I fiddle with 'B cut off' or 'B drive'?? To correct colors, what I did was load up a paint program and brought up a greyscales palette. I then painted horizontal strips, using darkest to lightest greyscales, so I had a fade. I also made sure to leave a large area of the screen pure white. I then played with all the R-G-B pots (including cut offs) until the greys looked prefectly grey, and the white background was as white as could be. You'll find all other colors will balance out like this. Don't use a screwdrive, I recommend a "TV alignment tool kit" (64-2223A) from Radio Shack. It comes with a plastic rod that fits perfectly into the pots and easy to turn. I paid about $2 Cdn for it (aprox $1.25 US). You might want to check about precautions, such as not grounding yourself, using a mirror and keeping one hand behind back or in your pocket. >....I didn't adjust any pots yet, as my girlfriend was present and >kept telling me to 'close that thing back up or you'll get yourself killed!' Sounds famillar, I had just about every friend and familly member tell me the same thing! ;-) Ah well, I'm still alive and I now have my monitor(s) more or less the way they should. I think one of my screens still has a problem with a red/pink tint on one side (as if a magnetic field were present) but I think it involves some more serious measures that would require a professional. >any help (particually from people who have done this before) is >appreciated. > >-arekusu > Mitchell Spector m_spect@vega.concordia.ca / spector@vax2.concordia.ca