how to determine if tachometer is "DEAD"??

[COP TZR]

I've aquired a Ducati Peformance tachometer and housing unit for my 2000 M750.  Everything is connected but I dont get any reading from the tach.  The needle moves ever so slightly but I think its only from vibration.  Is there a way I can determine if its defective or troubleshoot what the problem could be?  If I was to hook up a voltmeter to the end of the harness what sort of numbers should I see?

[COP TZR]

anybody?

[Drunken Monkey]

I forget exactly which wire you'd use to connect one of the older tachs.

On the FI models you tap into the signal wire for one of the coils (smaller connector, I believe)

Unfortunately I has no idea what the connections look like on the m750. If IZ_ memory serves me correctly, it's a gray wire going to the Vertical Coil.

[COP TZR]

its a fool proof wire harness that comes with the tach.  There are a total of 3 wires (red/black/green).  When I turn the key on any try with a test light I get good power and ground, so I'm assuming that the green wire is the signal wire?  If I start the bike and hook up a meter to the green wire will I get reading of any sort? 

[fstdy]

yup its the grey wire coming from the vertical cyl coil (coil on right)

[COP TZR]

hmmmmmmm.......... I'll have to check to see if that gray wire connects to the green wire leading to the harness at the back of the tach.  How can I test the gray wire to see if I'm getting some sort of signal?  Do I just use a test light or do I need to hook up a meter and what should I see?

[ducpainter]

hmmmmmmm.......... I'll have to check to see if that gray wire connects to the green wire leading to the harness at the back of the tach.  How can I test the gray wire to see if I'm getting some sort of signal?  Do I just use a test light or do I need to hook up a meter and what should I see?

I'd use a meter.

The signal voltage will most likely be the same voltage that triggers the ignition coil from the ignition pick up. I just don't know how many volts/millivolts it is.

[COP TZR]

could I jumper the power from the red lead to the back of the tach where the signal wire would attach to see if I get any movement of the needle?  I really want to get this thing to work.  If in fact its a faulty tach, can it be repaired?  Is there anyone on the forum that does repairs like that? 

[ducpainter]

I wouldn't put 12 volts to the signal input.

[MongoReturns]

I wouldn't put 12 volts to the signal input.

+1 on that, unless you really want a dead tach.  Just take the housing apart - it's not hard!  Give the little brass screws on the back of the tach a twist.  I'd think if you have the tach hooked up & both cyls run, the signal is fine.  The tach itself is sealed; I wouldn't take that apart.

[COP TZR]

+1 on that, unless you really want a dead tach.  Just take the housing apart - it's not hard!  Give the little brass screws on the back of the tach a twist.  I'd think if you have the tach hooked up & both cyls run, the signal is fine.  The tach itself is sealed; I wouldn't take that apart.

I've got the tach completely out of the cluster housing and see the 3 small brass screws.  Should I remove them completely and re-install and tighten or just snug them up some more?

[MongoReturns]

I've got the tach completely out of the cluster housing and see the 3 small brass screws.  Should I remove them completely and re-install and tighten or just snug them up some more?

Cool!  Just snug them up, then plug the thing back in & turn bike on.  Don't put the whole cluster back together yet!  Fingers crossed.

[COP TZR]

Cool!  Just snug them up, then plug the thing back in & turn bike on.  Don't put the whole cluster back together yet!  Fingers crossed.

I hope it works.  Does it matter if the tach harness is plugged into the left or right ignition coil?

[MongoReturns]

I don't think it matters, though mine's plugged into the left side.

[COP TZR]

I don't think it matters, though mine's plugged into the left side.

Mine is currently wired up to the right side, but I'll try the left side too if there's no success with the right side.  Fingers crossed