Re: Monitor problem

[Giorgio Morocutti <giorgio.morocutti@alice.it>]

On Wed, 06 Feb 2008 01:02:39 -0800, "Michael J. Mahon"
<mjmahon@aol.com> wrote:

>First, a few questions:
>
>1) When the monitor is warmed up, about what percent is the
>    brightness control turned to in order to begin to see the
>    "background" (black) raster?  10%?  60%?

Circa 50%


>
>2) If the brightness control is set to just below the point
>    where the background raster is visible, what percent of
>    the contrast control is required to get a good display?

circa 25%

>
>3) After setting the monitor up as in question 2), what setting
>    of the brightness control is sufficient to make the entire
>    screen (including the text) black?

circa 33%

>
>4) Did you notice any change in the normal settings of the
>    brightness and contrast controls when the problem began?
>
unfortunately, no !

>Without knowing the answers, there is one more capacitor that
>is a candidate for your problem:  C501, a 10uF @ 150v electrolytic
>near the horizontal output transformer.  It's the filter capacitor
>for the negative grid bias.  Note that the positive side of the
>capacitor is connected to ground, and the negative side (usually
>the "can") is at about -100v relative to ground.
>
I have made it, but no change.
(Only the new cap is 350VL rather than150VL)

Thanks Michael!
Ciao

Giorgio


Giorgio Morocutti
giorgio.morocutti@alice.it
Apple II & Apple III forever !