Apple B&W monitor schematic needed G090S
Roy J. Tellason
rtellason at verizon.net
Wed May 28 15:17:12 CDT 2008
On Tuesday 27 May 2008 21:49, John Robertson wrote:
> Anyone have this schematic for the Apple B&W 9" monitor? I have one that
> I am using, but the screen bias is way off so the screen is overdriven
> (horizontal retrace lines showing). Need to find if it is an adjustment
> or a bad/leaky capacitor.
No schematic, but look and see if there's a small board on the base of the
CRT. Usually is on most stuff of relatively recent manufacture, and that's
where they'd put the adjustment, or at least they do with color stuff.
You'll also find the pins of the CRT labeled in many cases, which makes it
easy to determine the bias of the tube -- cathode voltage and g1 voltage
should be very different, at least 20-25V for a mono monitor, maybe even
more, depending on the HV. Measure those and post back and we'll see what
it looks like from there...
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