Flickering on Second Sight

[jpoore@pro-palmtree.cts.com (James Poore)]

There were a couple of posts asking about the source of flickering on
monitors connected on Second-Sight boards.  The posts also mentioned
flickering of leds on a Transwarp and Zip GS accelerator boards.
These posts suggest to me that those problems are power-supply related.
One of two possibilities are probably present.
1) The power supply connector on the GS is more than likely burning the
contacts inside the connector.  This can be verified by discoloration of
the white plastic housing.  The solution is to change the pins in the
connector.  The connector is a Molex KK-156 Connector.  The original pins
contact the post on only one side.  When replacing the pins, use a new
"Trifurcon" pin that contacts the post on three sides.  This results in
better current transfer and less heat thru the connector.
2) The power supply itself is maxed out in the current dept.  This can be
due to aging capacitors in the power supply or just due to drawing the
maximum current the power supply can supply.
I am a firm believer\ in replacing the internal GS supply with an outboard
PC type power supply with a rating of 150-200 watt units.  An umbilical
cord thru one of the cutouts on the back of the GS makes the connection.
Removing the power supply out of the GS cabinet also helps the reduction of
heat inside the GS for more reliable operation.  Running a "barefoot" GS, I
am not certain how much power the accelerators consume but I would imagine
they consume a lot as well as do 4 and 8 meg ram cards.  The second sight I
would imagine also consume a goodly amount of power.  If anyone has any
more questions concerning this or similar problems, just send me some
e-mail and I will give you a reply.

Apple IIs Forever :)
Jim


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