Craig Bower wrote:
"Bill Garber" <willy46pa@comcast.net> wrote in message UPKdnT-yk9jAUIvfRVn-tw@comcast.com">news:UPKdnT-yk9jAUIvfRVn-tw@comcast.com...The only problem with pulling power from the video port for the monitor is, it flickers on floppy accesses. I have a 9" monochrome that I use on IIc and IIgs and the flickering on floppy accesses is very disturbing. An external power supply would be more desireable. :o)Hi Bill, That would become a major annoyance for sure. Hopefully there's a way around it with a capacitor or 2! :)
There are two separate problems: enough power, and regulated power. I don't know (offhand) how much an external device is permitted to draw from the video expansion connector, or what voltages are provided. Since it sags with floppy access, I'm guessing that it's the +12v line (used by the floppy motor). The permissible current drain would have to be at least as large as what the LCD requires or it's a bad idea to use it. The second problem is regulating the voltage supplied down to the level required by the LCD and keeping it stable. That is easily done with a voltage regulator if the required voltage at the LCD is at lease 1.5v less than the voltage supplied. If both the current and the voltage requirements are met, then the connection is straightforward. -michael New Applesoft BASIC interface for NadaNet networking! Home page: http://members.aol.com/MJMahon/