The landing light had a wire shorting to ground causing the breaker to
trip. The avionics issue looks like it was a loose wire to the avionics
bus. At least we'll see anyway. Nothing glaringly obvious like the
landing light.

Jon Kraus
'79 Mooney 201
4443H @ TYQ

Dan Luke wrote:

"Jon Kraus" wrote:


The breaker for the landing light is tripping. In a Mooney it is built in
to the switch and the switch will not stay on. I'm thinking that there is a
short somewhere but I don't know why that would cause the whole avionics
bus to go flakey...


Ah, that's different. That might account for some crazy symptoms if it's an
intermittent, high resistence short to ground. It could be pulling the
voltage down enough to make the avionics act up if *they* have a power or
ground connection problem. Perhaps a wire is being pinched somewhere, so
that changing the rpm causes the airframe to flex enough to affect the short.

At least the LL breaker gives you a clue where to start looking. I'd go back
to where the bus feeds the LL circuit and disconnect it, then see what
happens. I'd also still check all the ground and power bus connections,
master switch, etc. for high resistance, as you might have one of those
delightful two-headed gremlins.

Good luck and keep us posted.