Power for the clock in an M20K

[M20Kid]

I have an '81 M20K and the clock suddenly stopped working when I changed the ships battery some time back.  Assuming the death of the clock was unrelated to the ships battery I just left it alone.  Talking to my mechanic, though, he brought up the point that the clock is hardwired to hot battery because it runs all the time.  He thought maybe the wire that powers the clock may have come loose during the swap of the battery.  Excited, I pulled the cover off the side of the plane to look for any loose wires around the battery.  What did I find?  Nothing that looked like a smoking gun.

Can anyone help me identify the power lead for the clock?  Where does it connect to in the mass of wires running to the battery?

[carusoam]

Start at the clock, and work your way back…

In the most recent Mooneys…. There is a keep hot circuit…. Not directly connected to the battery because it has fuse protection… the fuse is close to the battery… probably at the hot post of the master relay…

Other things that are often in the keep hot circuit… radio memories, and the cigarette lighter…. Long bodies keep the interior light in the baggage compartment alive as well…

See if that is helpful…?

-a-

[tmo]

In my 1980 M20K there is a wire with an in-line fuse very close to the battery box in the avionics bay. I'd bet money yours is the same. It will likely be on the battery side of the power relay.

Mine keeps blowing randomly, tracing the wire to find where it broke is on my to-do list.

Tracing it back from the panel would be hard, as the wire is most likely hidden in a bundle of other wires running under the interior plastics.

[EricJ]

It could be anywhere from the master power relay near the battery to the master switch.   It will likely have its own in-line fuse, so check that.   If the fuse got blown, change the fuse and see if you can spot a reason why it might have blown.

 

[M20Kid]

Thank you all - I'll look first for anything that has an inline fuse; that seems a reasonable place to begin.

TMO - you're right, tracing it back from the main panel would be difficult and not a job I'm going to take on myself.  Now finding a loose wire or blown fuse near the battery seems an easy enough task.  Hmm ...

[Aerodon]

If you look at the electrical drawing for your serial number, you will see it shows a 5A fuse near the battery master.  And it looks like two additional circuits branch off after the clock, one to FF memory, the other to overhead cabin lights.  Are those working?  Then your clock has failed.

 

Aerodon

[carusoam]

Pray for the failed clock!

So many better alternatives available lately…

-a-

[Aerodon]

If you look at the electrical drawing for your serial number, you will see it shows a 5A fuse near the battery master.  And it looks like two additional circuits branch off after the clock, one to FF memory, the other to overhead cabin lights.  Are those working?  Then your clock has failed.

If you look here, I still have the drawings for your serial number.

 

Aerodon

[Aerodon]

2 minutes ago, carusoam said:

Pray for the failed clock!

So many better alternatives available lately…

-a-

Yes, my 55" flat screen TV won't fail, regardless of how many hours I leave it on.....

[kortopates]

i’d pull the clock first to see what you have. Or if you can determine manufacturer, google it. Your 40+ old Mooney may not have the original clock. My clock used a battery for power but ships power for lighting - it was not original equipment.


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