[Coco] cm-8

Kevin Diggs kevdig at hypersurf.com
Fri Apr 2 17:35:14 EST 2004


	I replaced three of the caps using jumpers (the power supply filter cap
a capacitor in the voltage booster circuit (c513), and a coupling cap
for feedback
to vert osc. (c509)). None helped. The DC voltage on the vert driver
output pin ((pin 6
on I.C 601, the sync processor ic) is off:  reading about 6. Should be
0.9. The DC
voltage on the vert deflection ic input pin (4) is also wrong:  reading
3.2. Should
be 0.8.

	The little picture of the vertical output says it should be 35v p-p. I
am getting
about 22v p-p. The raster only covers the upper 2/3 or so off the
screen. This makes
me suspect the "voltage booster" in the vert. deflection ic?


Stan Blazejewski wrote:
> Neither of those components would be faulty.  I would suspect any
> electrolytic capacitors associated with those though (won't be more
> that 3 or 4 caps), just replace them all & make sure the polarity is
> correct!!.  I'll lay odds that will fix your problem.
> --
> Australia isn't "down under", it's "off to one side"!
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