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Date Posted: 00:06:42 05/18/01 Fri
Author: Stuart Bell
Subject: Re: Performa 275 Analog board thoughts...
In reply to: Jeff Heflin 's message, "Performa 275 Analog board thoughts..." on 17:41:29 05/17/01 Thu

Hi!

If you're referring to the PCB link described on http://homepages.tesco.net/~macaddict/PCC2.html then that's the mod for 'normal' analogue boards to give -7.5v-ish on S1 for PowerCC systems. It's nothing to do with the VGA mod.

Takky describes it thus:

The 630 series logic boards require -12 Volts of power supply to the S1 pin. However, the boards do not use -12 Volts directly but regulate -12 Volts to -5 Volts. So if the minus power supply more than -7 Volts is satisfactory. The -10 Volts will be supplied through S1 pin by modifying analog board.
Caution: Since the ordinary output of S1 pin of the analog board is -5 Volts, the the logic boards like ColorClassic / CC II or LC575 will be broken by connecting an analog board modified with this method.

* Remove the Jumper line J19 on the analog board.
* Connect the input terminal, which is connected to LP14, of the negative voltage regulator (L7905) at IP8 to the line from the S1 pin of the connector.

hth, Stuart

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