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40 minutes ago, siu1526 said:

Has anyone gotten rid of their light control box in their 1970 Mooney? If so what was use to replace it? Im getting tired of fixing it and it only lasting a few moths before i have to fix it again.

What's a "light control box"? I'm not sure my C has one, unless you mean the 3/4" round knob on top of the panel that turns on panel lights. The circuit board behind mine went out once, causing a total electrical failure on approach in the mountains, just after coming out the bottom of the clouds. Took forever to find a replacement . . . . several years ago (7? 8?).

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What's a "light control box"? I'm not sure my C has one, unless you mean the 3/4" round knob on top of the panel that turns on panel lights. The circuit board behind mine went out once, causing a total electrical failure on approach in the mountains, just after coming out the bottom of the clouds. Took forever to find a replacement . . . . several years ago (7? 8?).

that the one.. I saw someone selling one on ebay but by the time i decided to buy it i couldn’t find it any more..


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What's failing that you keep having to replace? 

First time around was a diode on the push to test circuit. Now the map lights and panel light aren’t working. Checked the the fuses in the back and they are okey, im suspecting a bad transistor this time. I will mess with it some more today and see what i find.


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Congratulations on finding a diagram! Whatever failed on mine did so spectacularly, leaving only wires and soot. Never could find a diagram to see what it had once been. Finding a replacement unit was quite difficult. Good luck with your search! If you find a modern replacement, please let us know!!!

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Congratulations on finding a diagram! Whatever failed on mine did so spectacularly, leaving only wires and soot. Never could find a diagram to see what it had once been. Finding a replacement unit was quite difficult. Good luck with your search! If you find a modern replacement, please let us know!!!

Thanks you!..... Hey i have a diagram of the box internal i got it from one of the members here. Not sure if it the same one in your airplane but i can e-mail it to you is you like. I’ve been thinking about getting rid of the automatic dimming circuit and replacing it with a switch and a resistor keep it simple haha. I will update you guys as i go.


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2 hours ago, siu1526 said:


Thanks you!..... Hey i have a diagram of the box internal i got it from one of the members here. Not sure if it the same one in your airplane but i can e-mail it to you is you like. I’ve been thinking about getting rid of the automatic dimming circuit and replacing it with a switch and a resistor keep it simple haha. I will update you guys as i go.

PM sent. My C has a rotary dimmer, nothing "automatic" about it. I'll get a picture tomorrow for comparison. 

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4 hours ago, siu1526 said:


Thanks you!..... Hey i have a diagram of the box internal i got it from one of the members here. Not sure if it the same one in your airplane but i can e-mail it to you is you like. I’ve been thinking about getting rid of the automatic dimming circuit and replacing it with a switch and a resistor keep it simple haha. I will update you guys as i go.


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Instead of e-mailing, how about posting it in the download section?  Someone else who may need it in the future will probably appreciate it.

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Instead of e-mailing, how about posting it in the download section?  Someone else who may need it in the future will probably appreciate it.

I thought about it but it was sent to me with some writing saying it was okay to share but not to post and i would like to respect that. 29060f7209d2e6a3ca4ec00ac1264701.jpg


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5 hours ago, siu1526 said:


I thought about it but it was sent to me with some writing saying it was okay to share but not to post and i would like to respect that. 29060f7209d2e6a3ca4ec00ac1264701.jpg


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Yes, likely the same member sent me the schematic and requested I not post.

Note that at least one of the transistors is germanium, NOT silicon!

I'd be careful trying to replace the circuit with just a rheostat as the rheostat would now have to dissipate all the power that the heat sunk transistor was previously dissipating.

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Yes, likely the same member sent me the schematic and requested I not post.

Note that at least one of the transistors is germanium, NOT silicon!

I'd be careful trying to replace the circuit with just a rheostat as the rheostat would now have to dissipate all the power that the heat sunk transistor was previously dissipating.

 

Thanks for the heads up.. I was looking at the drawing earlier and decided to get rid of the rheostat all together and replace it with a SPST switch...

 

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Well i’m happy to say i have cockpit lights again. Got rid of all the monkey motion goin on in the control box, replaced the rheostat with a SPDT switch and moved all the diode for the warning lights down by the connector. Now i’m thinking about LED bulbs for the map lights and theDome light.. Anyone know where I can find LED replacement for the Map lights and Dome light??

821f676506cf2205e6d06f1fead751aa.jpg

3b87fd85bf2c43b5de8a0261c769524d.jpg Diodes inside the F4 tape..

4878a3bc8f60c1b3a39d266ee43ede80.jpg8bf2854f9388d574303cd031ff3acd10.jpg




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Damn!  You gutted that puppy!
Should be reliable, now...nothing left to fail

Yesss!! Should be way more reliable now.. Im going to draw what i did and post it.. Might help someone else down the road one day. It really nice to have cockpit lights again.


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3 hours ago, siu1526 said:


Yesss!! Should be way more reliable now.. Im going to draw what i did and post it.. Might help someone else down the road one day. It really nice to have cockpit lights again.


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That would be cool. Thanks. I'm going to be redoing my panel shortly and trying to decide what to do with dimming

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2 hours ago, Yetti said:

PWM for dimming.   Works on LEDs also.    This one looks pretty similar to the one on Aircraft Spruce.  https://www.amazon.com/Controller-DROK-Regulator-Adjustable-Regulation/dp/B016Q8APUY/ref=sr_1_9?keywords=PWM&qid=1563749756&s=electronics&sr=1-9

Be REAL careful with that thing.  It screams EMI/RFI...YIKES!  Open frame switcher design is not the best idea around modern avionics.  Also, that particular model is a bit overkill at 1 kilowatt!!

Just sayin'

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When mine went out years ago I found an STC'd rheostat replacement system. Haven't had a problem since. It was somewhat expensive for what it was however. 

Question and disclaimer- please believe me, I'm not knocking your work but I am curious to learn what route you will take for approval of the change in circuitry? Minor alteration sign off by an A&P or some other route like a 337? 

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When mine went out years ago I found an STC'd rheostat replacement system. Haven't had a problem since. It was somewhat expensive for what it was however. 
Question and disclaimer- please believe me, I'm not knocking your work but I am curious to learn what route you will take for approval of the change in circuitry? Minor alteration sign off by an A&P or some other route like a 337? 


I looked at rheostats online but i just wanted a simple on and off switch, i don’t fly at night very often but it nice to have some sort of light in the cockpit for those dark afternoons. After some research i figure a switch was the most reliable and maintenance free option.. As far as sign off i’m an A&P and i consider this to be a minor alteration, meaning a logbook entry will suffice.


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I was actually thinking the same thing (as a Minor Alteration). A&Ps can do a lot more minor alteration sign offs than they currently do if they just think about it. That's why we have the option. I did one for a Robbie helicopter for a bar to hold a 496 GPS on and then went and got a 135 on the machine and the Feds had no issue with my sign off. 

My rheostat like I said has never given me problems but it was pricey. 

You really simplified the system ! 

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I was actually thinking the same thing (as a Minor Alteration). A&Ps can do a lot more minor alteration sign offs than they currently do if they just think about it. That's why we have the option. I did one for a Robbie helicopter for a bar to hold a 496 GPS on and then went and got a 135 on the machine and the Feds had no issue with my sign off. 
My rheostat like I said has never given me problems but it was pricey. 
You really simplified the system ! 


Exactly... Just because it not in the MM doesn’t mean it imposible to do or fix. I think as long as it doesn’t affect weight, balance, structural strength, performance, powerplant operation, flight characteristics and airworthiness the feds are happy.


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