[Marc] We want to first look at these little things, which is from a viewer - thank you Austin!
And it's from the Apollo spacecraft. And Mike, you have been working on it...
[Mike] Yep.
[Marc] ...finding what it is.
[Mike] Yep.
[Marc] What is it?
[Mike] They are Lunar Module caution lamps. These are used for the rendezvous radar "no
track" light, and also for several ECS caution lamps, about quantities and things like that.
[Marc] And I never noticed them,
because they look gray. They look like a push button. Can you hold them for me...
[Mike] Yeah. [Marc] ...so I can do a close-up on it.
[Mike] Yeah, they are gray cylinders that kind of look like buttons.
[Marc] So I never noticed them until Austin
told me about them. And you didn't know either, you hadn't noticed them either?
[Mike] Nope.
[Marc] They're just lamps.
[Ken] They have one test diode!
[Mike] Yeah, they have an integrated lamp test diode.
There's three pins on the back here, we'll show you the schematics.
So there is the rendezvous radar "no track" light here. There's several of them: CO2, H2O sep.
[Marc] Well, if something goes wrong basically.
[Mike] Yeah, yeah, they're all caution lamps.
[Marc] And we don't find them in the Command Module,
right? I don't think I ever saw one of these.
[Mike] I don't think so. They have Grumman specification numbers on them,
so they might just be a lunar module thing.
[Marc] All right!
[Mike] Their part number is LSC 350-80610-02.
And if we look at the Grumman schematics for the radar section - this is a part list.
So you can see "no track caution light", LLC 350-80610-02.
So, you know, part number matches. This says it should have a yellow lens.
They came in red too, I think.
This is sort of systems level, how they're wired up.
There's a caution warning DC dimmer circuit, and the lighting control assembly
that dims from two to five volts. So, these lights have five volts on their
power pin always. When the subsystem wants to light the caution lamp it grounds pin 2.
[Marc] The other side.
[Mike] Yeah. And then these diodes are built in to the light, and go to the lamp test.
[Marc] Yeah, lamp test. I discovered on my own that you needed a diode...
[Mike] Yeah!
[Marc] ...because if not, you are going to short them all together, and when you light one,
you light all of them. So lamp test needs an extra diode. So that's the third pin,
it's the one that has the diode to it.
[Mike] This is the elementary functional diagrams for the lunar module, that show
all the things in more details. So you can see the pin one, two, and three for the light.
[Marc] Very cool, let's light it up!
[Mike] Yeah, let's do it!
One power, two ground. Okay!
[Marc] Yeah, okay. So I have it hooked up to the power supply. I've already pre-adjusted it. So
that's zero volt. That's 2.5V. It's fairly dim!
And that's five volts.
Ooo!
[Mike] It's very orange!
[Marc] It's very orange, and it's very
eerily even. Although in the camera it doesn't look like that, to the eye...
[Mike] Yeah, to the eye, it's very orangey, very flat.
[Marc] It doesn't look like an incandescent bulb at all. Very flat.
And it has a super wide view angle too. So, it's really meant to be visible from an oblique angle.
Very uniform. You can't tell the depth on it, right, when things are so uniform?
So, wow, beautiful indicator we didn't even know it existed! Thank you Austin!
[Mike] Yeah, thank you!
[Marc] We'll use it for something.
Oh, ah! It's really beautiful in the dark!
[Mike] Yeah, it is!
Let me take a picture of it before you turn it off.
[Marc] You want it at full blast?
That’s it for our light-hearted Franlab inspired video - as you can tell we get
easily entertained by over-engineered stuff that glows or clicks. And we’d like to thank
our viewers and Patreons for the many unique items they keep donating to the channel.
Thanks again Austin, and see you in the next episode!