RE: Convert 6 cyl tacho for use with 4 cyl

["Scott Feaver" <scott@j-body.com>]

I changed a Tach for a 91 Sunbird from 4cyl to 6cyl.  All I ended up doing
is changing the .047uF cap to a .033uF.  The circuit they use is almost
exactly the circuit in the application notes for the LM1819 chip off of
National Semiconductors website.

Scott

-----Original Message-----
From: owner-gmecm@diy-efi.org [mailto:owner-gmecm@diy-efi.org]On Behalf
Of Ludis Langens
Sent: Monday, May 22, 2000 7:27 PM
To: gmecm@diy-efi.org
Subject: Re: Convert 6 cyl tacho for use with 4 cyl


Shawn Lin wrote:
>
> In my '90 Grand Prix instrument cluster, the resistor is on the circuit
> board very close to the terminals that the electro-mechanical motor
> assembly plugs into.  The resistor is etched onto the back of a 14-pin
> DIP which is white in color.  I can't remember, but I think the 14-pin
> DIP has no function except as a surface for the resistor to be etched
> upon.

If the Grand Prix tach is like the other electronic GM tachs I've seen,
it uses the LM1819 chip.  The "white 14-pin DIP" contains most of the
resistors needed by that circuit.  The calibration resistor on the top
layer is just one of them.

--
Ludis Langens                               ludis (at) cruzers (dot) com
Mac, Fiero, & engine controller goodies:  http://www.cruzers.com/~ludis/


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