Alternator Tach Signal

[Amwasp]

Hi,
My VDO tach hasn't been the same since I had the alternator (Baldmar 7 series) rebuilt. When the alternator went it may have fried the tach but I didn't think so because the electronics work even though the analog dial does not.
When I crank the engine, the dial goes from 0 to top of range as it performs it's auto test. But after the test, the dial does not move from zero. I pulled all my manuals and everything on the web I could find but found no reference to the issue. I e-mailed the tech department at the company that bought VDO from Seimens but they were not responsive. I checked the continuity from the alternator pickup wire to the tach and it's good. I tried making the adjustments to adjust the tach by inputting the pulse rates and the system took the numbers OK, but the dial still reads zero.
Finally, the question...is there a way to test the alternator at the AC Tap to be sure that it is sending properly?
Thanks

[donradcliffe]

Best to use a scope, but you should be able to put a multimeter between ground and the tach output of the alternator and read something on the order of 10 volts on the AC volts scale.

[windsaloft]

I actually found that calling Balmar helped me the most when we ended up having to deal with alt/tach issues.

[David M]

I second that concerning Balmar tech support.