mooney panel lights

[N7149V]

I have the schematic for the dimmer sub panel for my Mooney M20F. I got it from Bill Wheat who designed the panel for Mooney. I have it in a PDF file but it wouldn't attach to this reply properly. Contact me and I'll send it to you. I am having the same problem with my panel lights. Also the up and down gear indication lights will not illuminate either. I checked all of the diodes and replaced a two that were bad. That didn't fix the problem though. Radio shack has the diodes for $1.69 for two. They are the 600V 1 amp diodes that are in the panel. I checked my rheostat and it works according to my meter, but no power is getting to it to light the  instrument lights when I reinstall the panel. The gear up and down lights won't light with the press to test, but the other warning lights will light up. I have searched for broken wires but have not found any. Also found one of the F-01 gray cap fuses on the back was bad. Where do I get those fuses? And how do you test the transistors? Where can I get the transistors or equivalent one?

 

[jetdriven]

Earlier in this thread are the part numbers for the transistors. You can get them and the F01 fuses from mouser electronics. 

[N601RX]

Quote: Barry

 Interesting it worked. A 2N2016 bipolar transistor and a MOSFET are biased entirely differently ... the MOSFET working more like the old electron tubes by clamping the electron flow by reverse biasing the gate and the bipolar transistor by forward biasing the base/emitter junction and reverse biasing the base/collector junction.

     Maybe that is why it's getting hot...

[N7149V]

This schematic of the Mooney dimmer switch lighting sub panel is the schematic that covers my 1974 Mooney M20F and others including a lot of M20J's. I got this schematic the other day from Bill Wheat who designed this sub panel for Mooney about 40 years ago.

I just need to find the proper transistor equivalents and to find those F-01 fuses from another source. Mouser website says you have to buy a minimum of 48 of them at $21.78 each or $1045.44 for the order! 

Still trying to resurrect my dimmer switch sub panel. The 2N2016 transistors seem to be the ones that burn out in the sub panel and take one or both of the F-01 fuses with them.

[N7149V]

This site won't attach the M20F dimmer switch sub panel electrical schematic PDF file. This schematic would be a great help to most of the Mooney owners with problems in the sub panel. Any suggestions?

[N7149V]

These are the 2N2016 equivalent transistors according to the Bipolar transistor cross reference search that I did on the internet.

 
1. 109T2 
2. 2N2016 
3. 2N5560 
4. BDY58 
5. BDY58R 
6. BLX26 
7. BLX27 
8. BLX29 
9. BLX30 
10. BLX35 
11. BLX36 
12. BUR50 
13. BUR50S 
14. BUR52 
15. BUT13 
16. BUT13P 
17. BUT14 
18. BUT15 
19. BUT16 
20. BUT33 
21. BUT34 
22. ESM16 
23. ESM16A 
24. ESM16B 
25. ESM18 
26. MTC35-300 
27. ZT2016

[N7149V]

There are 152 transistors that are the 2N442 equivalent transistor according to the Bipolar transistor cross reference search that I did on the internet, so these are much easier to duplicate.

[N601RX]

The physical package of the 2N2016 is shown as a T0-36.   This package will be hard to find.   Can you confirm this or post a picture?  Also find out what caused the original to fail before installing the new one.  If a transistor is exposed to a shorted condition it will be destroyed within a couple of miliseconds.  The fuse is just there to protect the wire, it will not blow fast enough to protect the transistor.

In the schematic post above the transistor is just used as a power amplifer, so several of the parameters such as frequency response will not matter.  The potemeter provides a small control current to the base.  The transistor then allows a larger porportional current based on its gain factor to flow  through the collector emitter junction.  Think of the transistor as a metering device for the current flowing through the collector emitter.  The amount of current that is allowed to flow is based on the current that flows into the base.

[jetdriven]

its because they are not MOSFET ttansistors.  I dont know where I got that. They are just regular NPN. 

Quote: N601RX

 Interesting it worked. A 2N2016 bipolar transistor and a MOSFET are biased entirely differently ... the MOSFET working more like the old electron tubes by clamping the electron flow by reverse biasing the gate and the bipolar transistor by forward biasing the base/emitter junction and reverse biasing the base/collector junction.

     Maybe that is why it's getting hot...

[N7149V]

I have about six of the 2N2016 transistors that I bought as spares when I repaired my dimmer switch panel and I will be glad to sell them for what I paid for them to anyone that is in need of them to get their Mooney panel up and running again. I also have the factory detailed schematic that is not in the Mooney maintenance manual. The transistors cost $45 ea. plus whatever it costs to ship them. I found that they were almost impossible to find unless you wanted to pay $124 for one. Hope this helps someone get their Mooney lights working again. Jim LaVore 305 731 6418 cel.

[aa777rob]

did you find your fuses for the panel lights?  my 1975 M20C panel light fuses were located under the throttle quadrant, which can be accessed by taking the throttle/prop/mixture handles off, then the cover, and the fuses are white about the size of pencil erasers, with 2 legs of them.  hard to get to but you'll see them in there.   3 of them.  my lights were inop, i looked everywhere for the fuses then finally found them one day there.   if someone already answered this, i missed it.  but that's where the fuses are. 

[Steveolyo]

My '69 M20F keeps blowing those little 5A Buss fuses. I found that with all of the panel lights removed the resistance of the circuit was .4 Ohms. So I began tracing the short into the dash. I pulled out the Rheostat assembly that includes three transistors in TO36 cases. There is nothing like this in the schematics. I checked the transistors, all good. Next I checked the Rheostat, it should be 250 ohms, but it has a 100 ohm resistor across it (also not in schematic) making it about 75ohms.

The only thing I could find was possibly that 100 ohm resistor lead could be intermittently grounding to the case. So I put some shrink wrap around it (see attachment, the shrink wrap is pinkish).

[Steveolyo]

  On 9/18/2011 at 3:38 PM, N7149V said:

This site won't attach the M20F dimmer switch sub panel electrical schematic PDF file. This schematic would be a great help to most of the Mooney owners with problems in the sub panel. Any suggestions?

Expand  

Convert the pdf to jpg or png. Even by taking a photo with your phone and uploading it though crude, would accomplish the task.

[Guitarmaster]

  On 5/10/2016 at 4:03 AM, Steveolyo said:

My '69 M20F keeps blowing those little 5A Buss fuses. I found that with all of the panel lights removed the resistance of the circuit was .4 Ohms. So I began tracing the short into the dash. I pulled out the Rheostat assembly that includes three transistors in TO36 cases. There is nothing like this in the schematics. I checked the transistors, all good. Next I checked the Rheostat, it should be 250 ohms, but it has a 100 ohm resistor across it (also not in schematic) making it about 75ohms.

The only thing I could find was possibly that 100 ohm resistor lead could be intermittently grounding to the case. So I put some shrink wrap around it (see attachment, the shrink wrap is pinkish).

Did you ever remedy your problem?

Sent from my iPad using Tapatalk

[Yetti]

If mine were to go south, I would just upgrade to what is in the later model Mooneys   https://www.amazon.com/Yeeco-Controller-Regulator-Switching-Indicator/dp/B00XE965RG/ref=sr_1_6?s=hi&ie=UTF8&qid=1468605651&sr=1-6&keywords=pwm+dimmer

[flyboy0681]

Boy does this thread brings back bad memories. A few years ago the panel lights went out in the J and we probably had four people look at it. Just when one had a ah ha! moment, it didn't pan out.

In the end we brought it in to Sarasota Avionics where they found a loose wire dangling which was hitting metal and baking the fuse. 

[jetdriven]

Standard procedure now is to pull the INST LTS circuit breaker anytime the glare shield comes out. Those bare connectors shorting to ground is what has blown the transistors and the 20$ fuses. 

[65C_flier]

Anyone know why the glareshield lights would get stuck on (78J)? I think the instrumemt dimmer that controls my glareshield lights has been on the way out for a while. On a recent night flight all panel lights were working (and dimming) properly, except the glareshield lights which were very dim. During taxi after landing the glareshield lights came on full bright and now they wont turn off even with both dimmers in the off position. Oddly, some of the other lights (flap indicator backlight) still dim. Internal failure of the dimmer switch?

I will probably change the glareshield lights for an LED strip and replace the dimmer with a PWM dimmer eventually, but I'd like to do a quick fix on the existing lights if possible.

Edited May 29, 2021 by 65C_flier

[jetdriven]

How do I recently installed and Max damn duo, that’s a fantastic piece of kit.   yes it is 400 bucks, but it works really well with two channels you can control your screens and your strip lights. They also make a dimmer for it they advertise for Pipers which clicks on like the factory does..  it turns on your indicator lights like the floor lamp and the compass, and then you have variable dimming to one channel. 

[A64Pilot]

If anyone is going the led route with a PWM dimmer, be sure to bench test before the install, for reasons beyond me many LED’s will flicker if used with a PWM dinner, even if you get a very fast PWM dimmer, but some will work just fine, oddly usually the cheap ones work fine.

Edited May 27, 2021 by A64Pilot

[PT20J]

  On 5/27/2021 at 9:18 PM, A64Pilot said:

If anyone is going the led route with a PWM dimmer, be sure to bench test before the install, for reasons beyond me many LED’s will flicker if used with a PWM dinner, even if you get a very fast PWM dimmer, but some will work just fine, oddly usually the cheap ones work fine.

Expand  

Good point. Pulse width modulation works by rapidly turning the load on and odd. Same idea as the way the burners are controlled on an electric stove, only much faster. With an incandescent bulb, the filament just glows more or less brightly but doesn’t turn off because the filament has enough thermal mass to continue to glow during the off times. But LEDs are turning on and off rapidly and it is only because that the retina cannot respond that quickly that makes them appear not to flicker. But, sometimes you can see it if you move your head. I remember when new LED taxiway lights were installed at KMRY. Whenever you would sweep you eyes across them, they appeared as a trail of dots because the motion of the image on the retina revealed the pulsing.

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