Re: [NTLK] Adjustable backlight?

From: Marco Mailand (Newton2k1_at_mac.com)
Date: Thu Jun 27 2002 - 02:50:08 EDT


> How would this work? Could other backlit Newts be modified to do this?
I've experimented a little bit with a separate white BL kit, that consists
of a small inverter and a BL foil of about 4 times the MP2k screen size and
thus consuming much more power. It was possible to dim the brightness from
totally dark to brightest by adjusting the input voltage or setting a
current limit at the DC supply. At this particular inverter the output
frequency changed slightly beside the AC voltage.
In order to do that in the Newton one would have to modify the inverter
circuitry, which sits somewhere distributed on the mobo, close to the
battery tray. It is possible but would at first require re-engineering of
the schematic of that part and finally modifying parts. A very simple
approach would be to replace the current limiting resistor of the power
transistor, which is switching the current thru the inverter coil by an
adjustable part.
Any modification like this would require modification of the case to have a
knob sticking out and would render the modified mobo unique or defect ;-)

--
With best regards / Viele Gruesse

Marco Mailand http://slsbd.psi.ch/timing http://slsbd.psi.ch/~mmailand https://www.paypal.com/refer/pal=YYD3VUXUVD2YG

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