Loose ground issue

[Rotorhead]

Hey all,

When flying around, it seems as though the cluster gauges are not reading correctly. Only saying so since when I press on the panel, all the instruments change the reading and read more closely to the JPI 730 onboard. Tried looking for any loose grounds but couldn't find a smoking bullet yet. The picture is behind the gauge cluster and just want to ensure it isn't missing a ground that some others may have hooked up. There are 2 ground straps on each end attached to the aluminum top panel though. 

Let me know what your thoughts are.

 

Edited April 30, 2022 by Rotorhead

[carusoam]

Cluster gauge gets grounded to the panel as well…

Have checked its connection?

 

Best regards,

-a-

[PT20J]

If it is grounded to the panel, make sure that the panel is grounded to the airframe. There should be a little copper strap that bridges at least one of the panel LORD shock mounts. 

[carusoam]

+1 for checking ground straps….

Know that some Mooney panels use rubber mounts that can often inhibit grounding…

-a-

[Rotorhead]

I've tried temporarily grounding the whole cluster gauge unit directly to the grounding panel with no real difference. I used one of the posts as circled and thought that would be a secure and solid grounding point. Am I missing something here? 

[201Mooniac]

If it is like on my 1980 M20J, those aren't grounding posts, they are terminals for lighting.  If you look under the tab you will see a hole for a light bulb for each of the gauges.  If you install light bulbs, you can daisy chain wire those terminals to provide power for the bulbs.

[Rotorhead]

18 minutes ago, 201Mooniac said:

If it is like on my 1980 M20J, those aren't grounding posts, they are terminals for lighting.  If you look under the tab you will see a hole for a light bulb for each of the gauges.  If you install light bulbs, you can daisy chain wire those terminals to provide power for the bulbs.

Well be damn I had no idea. May try out the lights once this ground issue is figured out. 

Appreciate the insight!

[carusoam]

Connecting wires randomly to things that look familiar may not work out very well….

This is why we have actual mechanics and avionics people…

You might want to use a volt meter and continuity tester prior to seeing sparks fly…

If you haven’t found the ground strap yet… that could be a hint you are chasing the right thing…

But, embarking on an electrical solution without the proper tools can lead to crummy results…

PP thoughts only, not an electrician…

Best regards,

-a-

[Rotorhead]

I tested for continuity and ground prior to "randomly" putting a test wire on to that post.

New Lord mounts that connect to the ground strap are on back order unfortunately. 
 

Edited August 1, 2022 by Rotorhead

[chriscalandro]

That doesn’t sound like a thing a ground would do. 
 

it sounds like a thing pressing on a gauge and effecting it’s inner springs and mechanisms would do.