The message to which you are about to reply is shown first. GO TO REPLY FORM



 VIEW    REPLY TO THIS MESSAGE Replies to this message will be emailed.    PRINT   SAVE 

need advice: adapting '94 940 speedo to an '87 740 700

posted by  M on  Thu Jan 17 14:47 CST 2002
Author: [PROFILE] [EVERY POST] [THREADS] [BEST POSTS] RSS Feed     [IGNORE ALL POSTS]
last visit: Sat May 1 10:12 CST 2010
[RELATED]

The speedometer sender produces a regular sine wave with pretty high amplitude. Original speedometer inputs start with an ordinary RC filter, not sure if I remember correct but 10kohm/47nF feels familiar. Cut-off frequenzies will look weird if you calculate but it works in reality. Use something like it in your own cirquit or you'll risk loading the signal to much, which may cause ABS warnings/shutdown.

940 speedo's are pretty sensitive and will accept a square-shaped positive signal. Try to get the zero part as close to ground as possible, though, since the original design detects sine wave zero crossings. The speedo input is very tolerant, btw - you won't risk damaging the internal cirquit if you shorten or give it a high voltage.

/Martin
--
65 121, 73 165






USERNAME
Use "claim to be" below if you don't want to log in.
PASSWORD
I don't have an account. Sign me up.
CLAIM TO BE
Use only if you don't want to login (post anonymously).
ENTER CAPTCHA CODE
This is required for posting anonymously.
OPTIONS notify by email
Available only to user accounts.
SUBJECT
MODEL/YEAR
MESSAGE

DICTIONARY
LABEL(S) +
IMAGE URL *
[IMAGE LIBRARY (UPLOAD/SELECT)]

* = Field is optional.

+ = Enter space delimited labels for this post. An example entry: 240 muffler


©Jarrod Stenberg 1997-2022. All material except where indicated.


All participants agree to these terms.

Brickboard.com is not affiliated with nor sponsored by AB Volvo, Volvo Car Corporation, Volvo Cars of North America, Inc. or Ford Motor Company. Brickboard.com is a Volvo owner/enthusiast site, similar to a club, and does not intend to pose as an official Volvo site. The official Volvo site can be found here.