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As the originator of this post, I though I should report my
solution to my "soft" CRT problem.

There is little doubt that the color monitor in my 8510C has
seen a lot of time... I think they all have by the time they
reach this age. So the CRT certainly has spent much of its
lifetime's worth of cathode emission by now.

Color CRT TV's of this vintage have a couple of sets of controls
that are used to compensate for circuit variations, CRT
variations and allow for a uniform final result. They are:

G2 or Screen, B.BKG, G.BKG, R.BKG, B.DRV, G.DRV, R.DRV,
Sub-Contrast, and Sub-Bright.

The G2, or Screen is used to set maximum brightness.
The [B,G,R].BKG are the color gun background settings.
The [B,G,R].DRV are the color gun drive settings.
Sub-Bright is used to set the midway brightness value.
Sub-Contrast is used to set the midway contrast value.

Basically, the G2 or Screen control (bottom control on flyback)
is there to set the maximum brightness value for a given CRT.
It is how you pop up a CRT that is just overall dim. It also
will wipe out the contrast when set too high, so be conservative.

The Sub-Contrast and Sub-Bright controls let you set the middle
value to something normal. They were originally there to allow
the TV set's brightness and contrast controls to have a decent
normal setting when they were in their midway detent... made the
customer happy that way.

The [B,G,R].BKG and [B,G,R].DRV controls set the individual
color levels at the high end, and the low end of their ranges.
They allow you to get a clean gray and a clean white color free
of color tinges at all brightness levels.

By some strange coincidence, there is only one cable (ribbon)
that drives the whole monitor, and it is long enough for you
to set the monitor on top of its normal location, and surprisingly
you can even reach all of the adjustments!

I cleaned the monitor of fuzz and HV carbon, measured resistors
that I know to be common problems, looked for bulging capacitors,
burned things, etc... Everything looked ok. Being a SONY, I
expected that.

I goosed the G2/Screen control until the graticule scales lit
to the brightness I wanted, tweaked the focus, and adjusted the
Sub controls for cleanest screen. No extraneous background lighting,
all of the possible colors showing clearly.

I think I am good for a while.

Thanks for all suggestions.

-Chuck Harris


Chuck Harris wrote: