Kyler Laird wrote in message ...
Jim Kaufeld writes:

First verify that your engines are sufficiently grounded. Then
verify it again. Check your alternators while you're there.

Kyler gives good advice.

The common mode rejection on most things that measure thermocouple
voltages isn't real high. So anything that can affect engine
grounds, etc can be a problem.

The GEM should be grounded to one of the engines. Doesn't the
1200 have 2 grounds?

Making sure that terminal is staked well would be a start.

Bill Hale A&P