VR241 vertical linearity problem

From: Charles E. Fox <foxvideo_at_wincom.net>
Date: Sun Nov 7 13:24:36 1999

>The fault is in the vertical scan. The top 2 lines (or so) are spread
>out, so that the top row of characters appears to have black lines
>running through them. In other words the vertical scan is very non-linear
>at the top.
>Adjusting the vertical linearity control improves things a little, but
>reducing the spacing at the top increases it at the bottom. What is odd
>is that the vertical position control affects the fault as well -- the
>problem gets worse as the picture is moved up the screen. This seems to
>rule out a problem with the ramp generator, since the vertical position
>control operates by applying a DC current to the yoke. The problem gets
>better as the monitor warms up.
>I've not dived into it yet -- and I suspect the electrolytics in the
>vertical output stage. I am wondering if anyone's seen this before and
>can suggest a possible cause.

        It wouldn't by any chance be a heavily magnetized CRT? Have you tried
degausing it?


                                                        Charlie Fox

                                Charles E. Fox
                       Chas E. Fox Video Productions
                793 Argyle Rd. Windsor N8Y 3J8 Ont. Canada
        email foxvideo_at_wincom.net Homepage http://www.wincom.net/foxvideo
Received on Sun Nov 07 1999 - 13:24:36 GMT

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