Wet Compass Lighting Power?

[blueskydriver]

Hey Guys,

You know that Wet Compass that just arrived; well, it has back lighting, but it only has one wire. So, this wire has a center and outer core. The center is solder to a screw on pin connector (center to pin), and the outer shielding is or looks like it just touches the screw on portion. This looks something like a RF connecter, but not exactly the same.

Anyway, what voltage should or could be used? Knowingly, it is 28VDC 400Hz CPS aircraft power normally, but with the recent discoveries in real gauges by Rob, Jack and others, can 5 VDC from the PSU be used? If so, would it be postive to the center and negative to the outer?

If someone has connected up the real wet compass lighting, please do tell how you did it...

BSD

[Nat Crea]

PM,

Mine is 5volts.
Doesnt matter which way you connect +ve and -ve on incandescent lighting

Nat

[blueskydriver]

Nat,

Thanks for the answers. I will give it a try today... Have you ever thought of making the compass work? My idea is put a servo with a magnet behind it, and then through trail and error to determine where it would match the sim in flight. By modifying the servo so it can do continous 360 degree turns would be the thing to overcome...

BSD

[Efe]

I've actually thought about this, as its a common piece of the 737 cockpit. I have a possible solution similar to what you suggested, the magnetic manipulation of the original instrument in relation to the outputs from FS to fool the instrument into displaying a correct reading. However, I have to get my hand on one and possibly take it apart to see if it would work physically.

[jackpilot]

Whaoo Guys, this beats the 1" gauge flat out! 

[Maurice]

Nat,

Thanks for the answers. I will give it a try today... Have you ever thought of making the compass work? My idea is put a servo with a magnet behind it, and then through trail and error to determine where it would match the sim in flight. By modifying the servo so it can do continous 360 degree turns would be the thing to overcome...

BSD

No need to say anymore. I rest my case.    .

Maurice

[Nat Crea]

Hey Mau...at least I haven't tried that.... yet ( )

Nat

[blueskydriver]

Working on the Wet Compass and found the following:

1. The power cable is exactly like an RF as described early.

2. If the Compass is old, likely the wire might not make good contact and short out your PSU.

3. Do not use the power cable and remove the rear cover to see the connections for the interior bulb.

4. Drill a small hole on the rear cover just above the light solder pins and solder two wires (V+ and V-), and then run a hard wire to your PSU 12 volts.

5. As stated in #4 use 12 volts as 5 volts barely lit the bulb enough to see it. Thus, 12 volts is fine. 18 volts and higher looks much better, but the PSU is only going to provide 12 volts for a standard connector.

6. Concerning the magnet/servo idea; it will be easy to do. While working on the compass and using a magnetic screwdriver tip, the compass was very sensitive and was affected a lot. Therefore, a small magnet on a servo will surely work.

Will try for pics later...

BSD

[jackpilot]

Had the 12V issue with the HF radio dial  lighting.
Was easier to change the bulbs to 5v "Grains of wheat"
Keeps everything 5V.

Just an idea.
Jack

[blueskydriver]

Hey Jack,

Yeah, keeping all 5 volts is good. However, since the bulb for the compass is rather unique in how it fits into the holder, changing to a different one would not work. It's one of those, you must have the exact bulb things...

The great thing is connecting it all up was simple. Just solder two small wires in the place where the old ones come in. Although, I had to redrill the hole at the back because the wires came out straight, as opposed to an angle from a top hole. You will not see the holes because they're behind the mount. Plus, with the PSU, it was just a changing over to the 12 volt side of the Molex connector.

Next up, magnet on the servo, but that will be a while because it requires lowering the overhead (to connect to the Opencockpit Cards). I do have several things to change already, but prefer to wait for at least 5 needed changes before lowering it (unless it's a high priority). Right now it's at 4.

BSD