Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!mailrus!ncar!umigw!mthvax!mathrich
From: mathrich@mthvax.cs.miami.edu (Rich Winkel)
Newsgroups: comp.sys.ibm.pc.hardware
Subject: Re: How to hook up turbo switch?
Keywords: turbo 386 clone ami c&t
Message-ID: <1990Aug10.212738.1837@mthvax.cs.miami.edu>
Date: 10 Aug 90 21:27:38 GMT
References: <2050@sud509.ed.ray.com>
Organization: U of Miami Dept. of Math. and Computer Science, Coral Gables, FL 33124
Lines: 26

In <2050@sud509.ed.ray.com> heiser@tdw201.ed.ray.com writes:
>I have a question about configuring the machine I am building.
>On the case I got, there is a "turbo" button with a two-wire cable
>attahced, with a jumper on the end (with two holes).
>On my motherboard, the "turbo" speed selection is made by setting a
>jumper on a 3-pin jumper.  The instructions say that for low speed,
>jumper pins 1/2, for high-speed, jumper pins 2/3.  
>What's the proper way for me to deal with this so that if I have the
>turbo pushbutton in the "out" position the system will be in slow speed,
>and if I have it in the "in" position, the system will run at the 
>high speed?

You need to look at the copper traces going to jumper pins 1 and 3.
If there are no traces going to pin 1, put the plug on pins 2 and 3.
If there are no traces going to pin 3, put the plug on pins 1 and 2.
The question of which switch position corresponds to the fast speed
is determined by the kind of switch you have and how it is wired to 
the cable.

If both pins 1 and 3 have traces going to them, then you need a different
cable and possibly a different switch.  You'll need a single pole, double
throw (SPDT) pushbutton (an SPDT switch has 3 solder lugs) and a three wire
cable.  Wire the center lug on the switch to pin 2, and one outer lug to pin
1 and the other outer lug to pin 3.

Rich