HP9836C colour alignment (grey scale tracking)

[Tony Duell]

> 
> Tony Duell wrote:
> >>> Has anyone ever done this setup and can offer any tips?
> >> Sounds like you can hardly make it worse.
> > 
> > Well, that's the problem. According to one of the HP manuals, 
> > misadjustment can cause damage. Of course that damage might not be too 
> > serious so it's probably worth giving it a go.
> 
> I'm guessing that they mean "driving the tube so hard the people across 
> the road complain" kind of damage.  Certainly I'd replace the two 

Yes, that was my thought. Excessive beam current could damage the CRT, 
the flyback transformer or bits on the video board. But I wonder just 
what 'excessive' is. I suspect I would notice it was far too bright long 
before anything was damaged.

> resistors that have gone high, and assess the picture from there.  If it 
> hasn't been twiddled by a previous owner then the chances are it'll be 
> "good enough".

Now that I don;t know. I doubt the previous owner did anything, but I 
don't know about before that. Equally, I don't know if these 3 resistors 
were ever the right values, it's possible they failed in service and 
nothing was adjusted (in which case the adjustments will be very nearly 
correct if I put good resistors in), or if the board was twraked when the 
user complained about poor colour performance or something. Or maybe the 
board as originally set up for the incorrect-value resistors that are now 
there.

Equally, I don;t know if the CRT has lost emission over time, it may well
be that I could safely turn things up a bit. 


-tony