Why Instal Both Hall & VR Circuits?

[Tailwind]

I'm in the process of building the MS-II and have a question about step 51. The instructions state:

51. ...there are two input circuits for the tach signal. One takes the square wave input from a hall sensor, optical sensor, or points. In most cases, you should install both circuits, and make the selection between them with jumpers. However, if you do not want to install the variable reluctor (VR) circuit as well as the Hall circuit, skip ahead to step #52.

As I understand it, the MS-II uses the processed output from the EDIS, OR it can take the raw input from the VR sensor and process that into a usable signal. I plan to use the Ford EDIS already installed in the car (and replace the current Megajolt Jr.) and am wondering why both the Hall/Opto circuit (step 50a.) and the VR circuit would normally be installed, if only one is going to be used.

Thanks for the insight

Bill

[trakkies]

I'm in the process of building the MS-II and have a question about step 51. The instructions state:

51. ...there are two input circuits for the tach signal. One takes the square wave input from a hall sensor, optical sensor, or points. In most cases, you should install both circuits, and make the selection between them with jumpers. However, if you do not want to install the variable reluctor (VR) circuit as well as the Hall circuit, skip ahead to step #52.

As I understand it, the MS-II uses the processed output from the EDIS, OR it can take the raw input from the VR sensor and process that into a usable signal. I plan to use the Ford EDIS already installed in the car (and replace the current Megajolt Jr.) and am wondering why both the Hall/Opto circuit (step 50a.) and the VR circuit would normally be installed, if only one is going to be used.

Thanks for the insight

Bill

I'm running EDIS8 direct to the opto input - but some have reported problems with this and use the VR input. IIRC, this has better noise filtering and pulse shaping circuits.

However, if building from a kit you've already paid for the bits so might as well use them. It will do no harm - and allows you to change at a later date for whatever reason.

FWIW I don't much care for the wiring method given in the manual for PIP and SAW - two different signals running in close proximity down the same paired cable with one screen seems to me allows the possibility of cross-talk. So I used two individual co-ax cables, with the screens only connected at the EDIS end. But this could just me being me.

[Tailwind]

Thanks for the response, Dave. I don't have the MS-II installed in the car yet, but I do have the relay box installed and connected to a Megajolt Lite for ignition. I've used a twisted pair shielded cable for connections from the VR sensor, the EDIS 4 box and to the Megajolt without problems. (At least that I'm aware of.)

I did buy a kit and , as you say, I do have the bits. My thoughts were that since I would need to work on the board to change the jumpers, that I could install the parts at that time. The only concern would be that I couldn't find where I put them, but I suspect that problems would occur sooner rather than later, so perhaps they wouldn't settle into the mess too deeply.

Thanks, again.

Bill