BTTF Time Machine Build Questions - Ask Me Anything

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Originally Posted by Timebender

So I’m guessing that all the indicator lights were converted to 12 volt (as they are Neon high voltage as stock), maybe LEDs? Also, for the bottom button, did you take a lens from one and just fit it over the push button?

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When the original cars were being built the keypads were found pretty much as you see them on screen as a complete assembly. They only had to be modified slightly to fit in the car below the time circuit displays. The keypad didn't actually function in any way other than the indicators being wire to light up when the TCD drive switch was turned on. All of the numeric displays were controlled by a separate box off camera to operate as you see on screen.

The stock TRW keypad assembly has a circuit board inside that has a push button soldered into it along with the LED's that are behind each indicator indicator. Production on the film just tapped into the circuit boards to make the lights work.

For the restoration we used a real keypad assembly and wired the lights and the actual keypad to function so it works like you see in the movie. You can actually enter dates into the keypad and the displays work based on the input.

All of the real TRW keypads are now long gone so most people building a replica need a casting of the green housing and a source for the rest of the internals. Luckily the lenses for the indicators used by TRW were an off the shelf component so today you can buy them as a separate indicator light. It doesn't matter what bulb type you get for the indicators since you throw away everything but the lens. The white keypad was also an off the shelf part made by GTE, and I believe TRW just assembled these components using their own custom circuit board to create the keypad assembly.

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Originally Posted by Mark D

For the restoration we used a real keypad assembly and wired the lights and the actual keypad to function so it works like you see in the movie. You can actually enter dates into the keypad and the displays work based on the input.

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So I'm guessing behind the white/clear lens on the bottom, you put in a momentary square pushbutton with the clear lens on top of it to cover it up.

Correct?

Yeah that's correct, the push button is below the lens, so when you push on the lens it activates the switch.

Here's a broken TRW keypad that was for sale that shows what the guts look like. There were a couple different variations of keypads, but this one looks to be original.

https://www.worthpoint.com/worthoped...ine-1827161268

Hey Mark, first off I would like to say thank you for all of this knowledge. I've been able to learn a lot from reading through this thread. I have a few questions if you don't mind.

I have been trying to find info on the switches that are on the overhead panel, but havent had too much luck. I saw that you PMed the PNs to another user earlier, is there any way that you would be able to send them to me too?

One of the other things I am looking at working on is the gold heatsinks on the rear bulkhead by the SID. I've heard that they were painted, but in the photos that I have seen of the originals they almost look like they were plated with another metal. Do you know how the original color was applied? For that matter, do you think it was something original, or something done when building the car?


Thanks for all the help!

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Originally Posted by Justin

Hey Mark, first off I would like to say thank you for all of this knowledge. I've been able to learn a lot from reading through this thread. I have a few questions if you don't mind.

I have been trying to find info on the switches that are on the overhead panel, but havent had too much luck. I saw that you PMed the PNs to another user earlier, is there any way that you would be able to send them to me too?

One of the other things I am looking at working on is the gold heatsinks on the rear bulkhead by the SID. I've heard that they were painted, but in the photos that I have seen of the originals they almost look like they were plated with another metal. Do you know how the original color was applied? For that matter, do you think it was something original, or something done when building the car?


Thanks for all the help!

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Are you talking about rectangular and circular red / white / yellow indicators in the overhead? Or the green / red rocker switches? or the green toggle switches on the black box? I can see if I've still got a list of PN's somewhere. I know the indicators were a real pain in the ass to order because you have to order the black housing, indicator lens, and bulb separately. They weren't all stocked at the same company back in the day so it took multiple orders from a few different places to get all the right pieces. And they are stupid expensive for what they are. 5 years ago it was like 300 bucks for a set, who knows what they are now. They do also sell the indicators as momentary push button or push on/ push off switches as well, but unless you are planning on actually wiring them up to something to function you are better off just getting the indicators only. The cost for the switches was like 30 bucks a piece plus the cost of the lens.

The gold heatsinks are made of aluminum and finished with gold chem film. It's a type of chromate conversion coating used to protect the aluminum from oxidation / corrosion. It's a similar process to how zinc plated steel parts are finished to look yellow after zinc plating. It's tough to find places these days that will still provide gold chem film coatings because it typically requires hexavalent chromium. Most places now only provide trivalent chrome conversion coatings because of industry standards and toxicity of the hex chromium. Some places that offer trivalent conversion coatings will add a yellow dye to simulate hex chrome, but it doesn't look exactly the same.

The gold finish on the heatsinks was definitely original. There are other markings and PN's inked onto the heatsinks that would have been covered up had they been painted over or refinished. The production team who built the car were actually really good about preserving part numbers on the parts. I'm not sure if it was intentional or not but it adds some authenticity to each prop that makes it seem a little bit more real.

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Originally Posted by Mark D

Are you talking about rectangular and circular red / white / yellow indicators in the overhead? Or the green / red rocker switches? or the green toggle switches on the black box? I can see if I've still got a list of PN's somewhere. I know the indicators were a real pain in the ass to order because you have to order the black housing, indicator lens, and bulb separately. They weren't all stocked at the same company back in the day so it took multiple orders from a few different places to get all the right pieces. And they are stupid expensive for what they are. 5 years ago it was like 300 bucks for a set, who knows what they are now. They do also sell the indicators as momentary push button or push on/ push off switches as well, but unless you are planning on actually wiring them up to something to function you are better off just getting the indicators only. The cost for the switches was like 30 bucks a piece plus the cost of the lens.

The gold heatsinks are made of aluminum and finished with gold chem film. It's a type of chromate conversion coating used to protect the aluminum from oxidation / corrosion. It's a similar process to how zinc plated steel parts are finished to look yellow after zinc plating. It's tough to find places these days that will still provide gold chem film coatings because it typically requires hexavalent chromium. Most places now only provide trivalent chrome conversion coatings because of industry standards and toxicity of the hex chromium. Some places that offer trivalent conversion coatings will add a yellow dye to simulate hex chrome, but it doesn't look exactly the same.

The gold finish on the heatsinks was definitely original. There are other markings and PN's inked onto the heatsinks that would have been covered up had they been painted over or refinished. The production team who built the car were actually really good about preserving part numbers on the parts. I'm not sure if it was intentional or not but it adds some authenticity to each prop that makes it seem a little bit more real.

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Well that is some great information on the heat sincs. Thank you so much! I'll need to start looking at my options for that.

Right now I have been looking for the rectangular and circular red / white / yellow indicators, but I was going to start looking for the rockers next, and would love to know about the green toggles if I could. I have heard about how expensive they are, and that they needed to be ordered as separate pieces, but I didn't hear that they were not all from the manufacture, I bet that is part of the reason I was having a hard time finding just the right model. I found several similar models, but none of them were quite the right shape. At this point I would like to get the actual switches, but your idea of just getting indicators is a good one.

Thanks again!

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Originally Posted by Justin

Well that is some great information on the heat sincs. Thank you so much! I'll need to start looking at my options for that.

Right now I have been looking for the rectangular and circular red / white / yellow indicators, but I was going to start looking for the rockers next, and would love to know about the green toggles if I could. I have heard about how expensive they are, and that they needed to be ordered as separate pieces, but I didn't hear that they were not all from the manufacture, I bet that is part of the reason I was having a hard time finding just the right model. I found several similar models, but none of them were quite the right shape. At this point I would like to get the actual switches, but your idea of just getting indicators is a good one.

Thanks again!

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The indicator parts are all made by AlcoSwitch (Tyco).

20x Indicator Body (Rectangle): 164TZ
10x Red Lens (Rectangle): 64T2
10x White Lens (Rectangle): 64T9

6x Indicator Body (Round): 164EZ
3x Red Lens (Round): 64E2
3x Yellow Lens (Round): 64E4

You'll also need 26 size T1-3/4 midget flanged base lamps.

If you want switch versions of the indicators be prepared to spend 2-5 times more. Also, the switches are much longer than the indicators and may not even fit behind the overhead panels. You may want to take measurements or buy a couple to test before spending over $1000 on switches that may not fit.

Momentary Switch (Rectangle): 164TL11
Push On-Off Switch (Rectangle): 164TL511

Momentary Switch (Round): 164EL11
Push On-Off Switch (Round): 164EL511

This makes me wonder if there’s a way to make inexpensive replicas of those indicator lights - maybe just the lenses alone.

The indicators aren't all that bad on cost but when you start looking at the switches...yikes.

When I got a set of these ~10 years ago it was with a group of builders and we did a group buy to get our quantities up. Most places that sell these have price breaks at higher quantities where it's a lot cheaper the more you buy. If you can find some other people that are interested in building an overhead assembly it makes sense to go in together on a parts run.

Or if you can afford it, buy 2-3 sets yourself and then sell them on ebay for more than what you paid, but for less than 1 set would cost alone.

Because these are fairly intricate electrical components I would advise against castings. Nobody wants to melt their car or start a fire trying to save a few bucks. The lenses are the cheapest part so it wouldn't make sense to cast those either. They are fairly complex 3 piece design and would make for some difficulty molding anyway.

http://dmctalk.org/attachment.php?at...3&d=1548689459

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Originally Posted by RamblinDMC

Thanks so much for the info! I was wondering about thee cutout dimensions of the readouts. I plan on using some LED displays coupled to an Arduino. Once the speedometer project is done, I'll start on the Flux.

Thanks!
Jayce

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Resurrecting this old discussion as I'm about to do similar on the speedo - GPS and Arduino.

I know the original segment displays are no longer available. In looking at what else is our there any recommendation?
The 0.56" seem too small and the 1.2" seem too big.

Also - it looks like at one point there were dimensions for the cut out but it looks like they're gone.
Anyone help with this too?

Cheers
Steve