AVR-Chat

Mark Graybill wrote:
> 20V of ripple is pretty high, getting it down to something like a  
> volt or two would result in a cleaner image. The problems you're  
> complaining of aren't related to ripple, however.
> 
> If your CRT is of the flat-screen variety then focus voltage will  
> need to be adjusted depending on where you are onscreen. If the face  
> is fairly spherical then this isn't necessary. I'd tend to suspect  
> the regulation on your focus power supply having some interaction  
> with the deflection cicuits if you're seeing focus go off when you're  
> deflecting the beam off center.
> 
> I don't know of any current production CRT controllers for  
> electrostatic deflection CRTs. There may be some out there, but I  
> haven't worked with any since the early 80's, and I suspect there  
> isn't much demand these days.
> 
> On the noise, be overgenerous on your grounding of the CRT shield.  
> Also, make sure the regulation circuits on your other power supplies  
> have a good response time and are relatively immune to noise themselves.
> 
> Your signals can look good on a scope but bad on screen because your  
> scope probes do a lot of filtering for you. Also, if you're using  
> dividers to access the high voltage outputs they'll clean up the  
> signal for you, too.
> 
> In the past, I have typically done deflection on an entirely  
> different board than the board that carries anode, gate and focus  
> voltages. The horizontal and vertical amps seem to be happier outside  
> the EMF of the other outputs.
> 
> Good luck!
> 
> -Mark G.


I'd like to know what he wants to do with this thing?

erikc