Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!ucsd!ucbvax!agate!monsoon.Berkeley.EDU!chao
From: chao@monsoon.Berkeley.EDU (Chia-Chi Chao)
Newsgroups: comp.sys.ibm.pc.hardware
Subject: Re: How to hook up turbo switch?
Keywords: turbo 386 clone ami c&t
Message-ID: <1990Aug11.050958.3723@agate.berkeley.edu>
Date: 11 Aug 90 05:09:58 GMT
References: <2050@sud509.ed.ray.com> <1990Aug10.200504.20168@cunixf.cc.columbia.edu>
Sender: usenet@agate.berkeley.edu (USENET Administrator;;;;ZU44)
Reply-To: chao@monsoon.Berkeley.EDU (Chia-Chi Chao)
Organization: ucb
Lines: 27

In article <1990Aug10.200504.20168@cunixf.cc.columbia.edu> cy5@cunixa.cc.columbia.edu (Conway Yee) writes:
>In article <2050@sud509.ed.ray.com> heiser@tdw201.ed.ray.com writes:
>>
>>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.  
>
>In your case, either pins 1 or 3 is not hooked up to anything. Thus, if
>3 is the one that is hooked up to nothing then having the jumper on 2/3
>is the same has an open circuit on 1/2.  Thus, installing your switch
>on 1/2 enables you to toggle 1/2 open circuit or closed circuit.  This
>enables you to get the "turbo" and the "standard" speeds.
>
>If pin 1 is the one hooked up to nothing, then the reverse is true.  Placing
>the switch on 2/3 allows you to toggle speeds.
>
>			Good luck,
>			Conway Yee, N2JWQ

On my motherboard, the 3 pins are used like debounced toggle switch.  Shorting
1 and 2 _LATCHES_ one speed, and shorting 2 and 3 latches another speed.  In
this case, a 3-wire (SPDT) switch is needed.

Chia-Chi Chao     chao@ocf.berkeley.edu   ..!ucbvax!ocf.berkeley.edu!chao