4 Mar
2003
4 Mar
'03
9:56 a.m.
Hello again,
I've got a Sinclair (well, Amstrad really, but it has Sinclair printed on
the front) monitor here, which claims to be a QL monitor. To the extent
that it has a captive QL-specific signal lead...
However, the display is too wide, and marginally extends past the bezel in
both directions; only by about 1/4 of one character or so, but just enough
to be seriously annoying.
So, today, I whizzed the back off to adjust it - but there's no "horizontal
size" pot :( There are trimpots for V.size, H.hold and Sub-bright. There's
You're looking for an adjustable inductor (coil) in series with the
horizontal yoke -- probably connected to the collector of the line output
transistor. OFten there are 2 inductors in series -- a normal adjustable
one (width) and one with an adjustable bias magnet (horizontal linearity).
adjusters for focus & brightness (or maybe
contrast, it was hard to tell
since it was simply labelled "Screen". There's also externally accessible
'Screen' adjusts the voltage on the first anode (sometimes incorrectly
called the 'screen grid' in the States) and is a brightness adjustment.
controls for V.hold, brightness & contrast. On the
back of the tube,
there's trimpots to adjust red & blue intensity (with two pots per colour).
Probably a gain and offset control for each colour.
It looks like there ought to be a green pot as well,
but there's no trimmer
there, just a fixed resistor.
It's normal to have _one_ control (normally offset) for green, since you
don't actually need all 6 to get the right grey scale tracking. But I
don't think you can necessarily get a correct grey scale with only 4
tweakers.
-tony