Dimmer replacement

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ateamer

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ateamer
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My 175 has the antique rheostat dimmers for the radios and red dome light. As part of cleaning up the panel, this is a good time to upgrade to current tech before they fail. All I have found is the $400 Maxdim dimmers, at least for certified switches. Is there a less costly alternative? Is there a way to make this one https://www.aero-lites.com/product-page/panel-mount-rotary-dimmer-12-28v-compatible acceptable? I have a really hard time believing that something as simple as a switch needs to cost 10 times as much because it comes with a piece of paper.
 
ateamer said:
Is there a less costly alternative?
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I've always treated this type of device as a standard part and would procure one from a local commercial electronics store. Perhaps your mechanic believes the same? The MaxDims are STC'd/PMA'd so they can sell them to the public hence their higher costs. There was an AD out once on certain Cessna dimmers but I don't recall the details. Perhaps check into the specs for the original dimmer and start there?
 
Cessna SEB92-33R2 - Overhead Lighting Console Installation Inspection (attached)
AD 93-24-15 - Cessna Models 150F, 150G, 150H, 150J, F150F, F150G, F150H, and F150J, 172E, 172F, 172G, 172H, 172I, 172K, F172E, F172F, F172G, F172H, FR172E, FR172F, FR172G, 180H, 180J, 185D, 185E, 185F, R172E, R172F, R172G, R172H Airplanes

Not familiar with what's on the 175's.
All the folks on the Cessna forums rave about the MaxDim units.
 

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ateamer said:
My 175 has the antique rheostat dimmers for the radios and red dome light. As part of cleaning up the panel, this is a good time to upgrade to current tech before they fail. All I have found is the $400 Maxdim dimmers, at least for certified switches. Is there a less costly alternative? Is there a way to make this one https://www.aero-lites.com/product-page/panel-mount-rotary-dimmer-12-28v-compatible acceptable? I have a really hard time believing that something as simple as a switch needs to cost 10 times as much because it comes with a piece of paper.
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The MaxDims have been standard equipment on the Pipers for at least 10 years, possibly more.
 
The MaxDim is rated for 10A loads vs 2A for the Aero-Lites unit. Probably not a problem if everything is LED though. Also FWIW, the output of Seaton Engineering's dimmers (MaxDim, MiniDim, etc) is raw PWM which doesn't work well with the dimming inputs on most modern avionics from Garmin and others. I suspect the Aero-Lite products are the same but I've never tested one of those.
 
What kind of radios?
 
ateamer said:
GPS175, KX-155, KX-125, GTX335, dual G5.
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Gotcha - and they all dim with your current "antique" dimmer? I wouldn't have thought that, but learn something new everyday.

If all is working well, I'd be tempted not to risk breaking something by trying to fix it. Just let sleeping dogs lie.
 
Forgot to add: The radio dimmer only dims Com 2 (KX-125). The Instrument Light (red dome light) dims the red dome light and the magnetic compass. The Garmins are auto dim.

The driver behind wanting to change the dimmer is that I’m going to move it from an added-on subpanel below the panel to an empty hole next to the other dimmer. The subpanel also holds two avionics breakers, and two spots are available for those next to the other breakers.
 
ateamer said:
That’s the long-term plan, but I’ll keep the King radio until it checks out.
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On a more serious note, the fact that the dimmer is only connected to that one device lends even more credence to the point that @Bell206 made in post #2 about it being a standard part.
 
If you really want to replace your two working dimmers, I would have new dimmer 1 work the compass and KX radio, and new dimmer 2 work the overhead dome light. That way you have control over a couple of things mounted in the instrument panel, and you can separately adjust the cabin lighting.
 
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