SW 990B tach and 970 transmitter?

[dec31]

I was wondering if anyone out there can tell me what exactly the function is of the 970 transmitter block for the SW 990B tach. What does this unit do. I did call SW directly and no one there could tell me, the company has changed hands so many time the info is no longer available http://www.yenko.net/ubbthreads/images/graemlins/worship.gif. I would appreciate the assistance
thanks Chris

[68l30]

FYI....990B is the transmitter......970 is the tach...



Steve

[SuperNovaSS]

Chris,


I believe all it does is reduces the voltage to the tach. I opened one up at one point and if memory serves me correctly the only thing inside is a resistor on the 12V area.


Jason

[Steve Shauger]

I am not sure, but the transmitter probably conditions the pulses coming from the distributor, and integrates them. Basically the # of pulses for a period of time represent a voltage, more pulses the higher the corresponding voltage is. The meter movement is a voltmeter calibrated to convert voltage to a corresponding RPM's.

[dec31]

Thanks for the input guys. May have to make a trip to a electronics shop and have them test it to figure out what it really does for sure.
Thanks again for your help
Chris