HP9836C colour alignment (grey scale tracking)

Tony Duell ard at p850ug1.demon.co.uk
Thu Sep 25 13:11:55 CDT 2008


> 
> On 24 Sep 2008 at 20:16, Gordon JC Pearce MM3YEQ wrote:
> 
> > Sounds like you can hardly make it worse.
> 
> I'd be sore tempted just to "eyeball" the adjustments, myself.  I 

Well, I think I have to, given that I am unlikely to get a photometer, 
and even if I do, I don't know how I would verify that it was claibrated 
correctly.

> imagine a photometer is essential if you care about things such as 
> color accuracy, but perhaps just checking white balance may be close 
> enough.

My plan at the moment is to check some other components on the video 
board, then replace all 3 resistors. Since the green channel is not going 
to be affected much by this (12.7k -> 12.4k), I'll leave that alone, then 
display a grey-scale pattern and adjust the gain and cutoff of the red 
and blue amplifiers for neutral colours. It may not be perfect, but I 
doubt it'll do any real damage, and if I ever do get a photometer I can 
give it a tweak (it is my machine after all....)

-tony



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