Tach Problems on 912A - Jan 2006

My tachometer will not read accurately above 5000 rpm. Beyond 5000, the
needle pins to the top of the scale.
We replaced one pickup with another, and the problem just got worse.
Both pickups have almost equivalent ohms, about 200.

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Date:         Mon, 30 Jan 2006 20:14:40 -0500
Reply-To:     Ximango Owners Group <XIMANGO@HOME.EASE.LSOFT.COM>
Sender:       Ximango Owners Group <XIMANGO@HOME.EASE.LSOFT.COM>
From:         Bruce Schimmel <bruce@SCHIMMEL.COM>
Subject:      Tach problem on 912A (81hp)
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My tachometer will not read accurately above 5000 rpm. Beyond 5000, the
needle pins to the top of the scale.

We replaced one pickup with another, and the problem just got worse.
Both pickups have almost equivalent ohms, about 200.

Anyone else have this problem?

Thanks,
Bruce
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Date:         Tue, 31 Jan 2006 00:09:44 -0500
Reply-To:     Ximango Owners Group <XIMANGO@HOME.EASE.LSOFT.COM>
Sender:       Ximango Owners Group <XIMANGO@HOME.EASE.LSOFT.COM>
From:         Ted Gordon <tedjgordon@ATT.NET>
Subject:      Re: Tach problem on 912A (81hp)
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Bruce:

I use a Rotax ULS on my new RANS and had tach problems. We've started the=

=20
engine but not yet flown the plane (it will happen soon). We had no tach=20=


reading at all and traced the problem to the tach meter itself. It was a=20=


UMA unit that requied 20 V peak to peak to activate, and should have been=

=20
triggered by 2 V. So the unit went back to UMA and we're waiting for a ne=

w=20
one to arrive. It took a signal generator (60 Htz should read 3600 RPM)=20=


and scope to diagnose.

Best
Ted