Volvo RWD 1800 Forum

INDEX FOR 1/2026(CURRENT) INDEX FOR 7/2003 1800 INDEX

[<<]  [>>]


 VIEW    REPLY TO THIS MESSAGE    PRINT   SAVE 

tach gone wild 1800 1972

CM;

It sounds like a classic "thermal intermittent"...fancy term from the electronics industry, which doesn't help much in fixing it...but if a number of you are experiencing the similar problem, it might indeed be a fault of the circuit design (some transistor does flacky things when that hot)...but at least now you have a high-tech name for it...

ORRRR, the calibration pot is mechanically intermittent and opening just when hot, sending the reading high...this is a well-known symptom and effect of the early tach (found in the carburated cars)...perhaps a similar thing is happening with the later tach also (I've never experienced in the '73ES)...I was lead to believe the circuit used is it is common to all Smiths tach (I have not been able to confirm this!) ...I had a circuit diagram of the tach which I will try to locate and post...

...I wouldn't say the tach "is .... on the way out." just yet...

Cheers






THREADED THREADED EXPANDED FLAT PRINT ALL
MESSAGES IN THIS THREAD

New tach gone wild [1800][1972]
posted by  C-Man  on Wed Jun 8 08:39 CST 2005 >


<< < > >>



©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.