Panel Lighting Troubleshooting

[AerostarDriver]

In my 71E, I had all my rheostat controlled lighting on the panel go out when I was adjusting a post light. Is anyone aware of a fuse that is on the panel lighting circuit?

I tried my best to look at the diagrams in the service panel and they seem to indicate only a circuit breaker is used but then the rheostat is part of the box at the top of the pilots panel with fuses in it. I assume I shorted the panel lighting as I found that the center pin of the light post was contacting the case ground after pulling the light, I have since fixed the light post but I still can not make the panel lighting work.

[jamesm]

The 67C has a circuit breaker that has a dome lights on same circuit. If I recall correctly up in the  headliner there extra  dead end wires going no where. also the rheostat above the pilot's head on the ceiling in the head liner  has wires the run down to the instrument lighting buss (terminal strip)  near/ above the pilot's knee from the rheostat I think the wires run down pillar pilot side near where the font and side windows meet.

 

hope that helps

[Yetti]

 

[N9405V]

The rheostat is part of a big mess of wires behind the panel. There should be a inline fuse back there somewhere.

 

 

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[0TreeLemur]

We chose to eliminate that big rheostat when we went to LED post-lights, replacing it with a tidy PWM.  Eliminated a smoke/fire risk.  Might be a good time to do that.

 

[Yetti]

On 5/8/2021 at 11:26 AM, N9405V said:

The rheostat is part of a big mess of wires behind the panel. There should be a inline fuse back there somewhere.

 

 

Sent from my iPhone using Tapatalk

Oh ya there are three fuses (assuming you have the three knobs) on the transistor board.   They are small micro glass Buss fuses.  The transistor board is located on top of the nose wheel well.   an Alum plate with 4 screws holding it on.

[MikeOH]

4 hours ago, 0TreeLemur said:

We chose to eliminate that big rheostat when we went to LED post-lights, replacing it with a tidy PWM.  Eliminated a smoke/fire risk.  Might be a good time to do that.

 

Was the PWM controller a TSO product?  I'd be concerned about EMI interference with GPS nav/coms.

[0TreeLemur]

9 hours ago, MikeOH said:

Was the PWM controller a TSO product?  I'd be concerned about EMI interference with GPS nav/coms.

Yes it is!  And expensive to prove it. 

At first I bought a $12 eBay special to test.  In ground testing there was a low hum in the overhead speaker with the PWM set below 100%.   So, I bought the TSO PWM unit and installed it. Same noise in the overhead speaker.  I think the TSO PWM cost about $250.  My guess is that my old Terra audio panel is picking up the noise through the dimmer circuit. 

I could fix the low hum with a new audio panel.   But, I can't hear the low hum when the engine is running, and it is below the squelch limit on the intercom.  I can take pride in knowing that I installed the TSO PWM module. 

[DanM20C]

On 5/8/2021 at 12:39 AM, AerostarDriver said:

Is anyone aware of a fuse that is on the panel lighting circuit?

The fuse is a good place to start.

Attached is the schematic of your dimmer/annunciator box.  I believe this design was used 69-76.  Many of the early ones don't have Q3 and F2 but everything else is the same. 

Cheers,

Dan

 

800275 REV R.pdf 800275 Connections.pdf

[AerostarDriver]

41 minutes ago, DanM20C said:

The fuse is a good place to start.

Attached is the schematic of your dimmer/annunciator box.  I believe this design was used 69-76.  Many of the early ones don't have Q3 and F2 but everything else is the same. 

Cheers,

Dan

800275 Connections.pdf.URL 268 B · 1 download 800275 REV R.pdf.URL 268 B · 1 download

Dan,
I am not sure what I am doing wrong but I cant seem to open these. It takes me to a part of mooneyspace saying the file is no longer available.

[DanM20C]

Lets try these.

Cheers,

Dan

800275 Connections.pdf 800275 REV R.pdf

[AerostarDriver]

23 minutes ago, DanM20C said:

Lets try these.

Cheers,

Dan

800275 Connections.pdf 54.94 kB · 0 downloads 800275 REV R.pdf 2.23 MB · 0 downloads

Fantastic, Thanks!