Tom Hudson posted this on the Space 1999 Props Facebook group, of all places. It’s an incredible teardown of the S3 vac-form Mk VI B, showing the construction, design, electronics - what a dream! It looks like it’s two different VI B units - one with the thicker hinges and an early one with the tiny hinges. Note the slotted screw by the EMRG button, as per this thread.
There’s some really great insights here, particularly that the ABGD lights are 4 x small rectangular LED modules glued together!
A couple of tricorders Ed and I built for Star Trek: The Next Generation. The older of the two is a real wreck now. The story: Ed got a call from Paramount on a Monday – they needed new working tricorders the next week. That gave us 5 days to make three of them. I banged out the circuits in two days and shipped them to Ed; he made the cases and finished them. I had none of the parts I really needed to build them the way I wanted, so I used what I had on hand. The circuit barely fit into the case, but it had DIP switches so they could turn the various lights on and off, and a couple of trimpots for adjusting the sequential LED speed. Funny detail: You can tell when they started using our props on the show – the originals had the four big LEDs to the left of the display blinking 1-2-3-4 top-to-bottom; Due to a wiring mistake, ours blinked 4-3-2-1 bottom-to-top. So we could always tell right away when watching the show when they were using our props! More details on individual photos.
The later revision tricorder we built for Trek. MUCH heavier-duty hinges so they stood up much better under filming. Also better LEDs. Same cheap paper labeling…
One of the first 3 tricorders we made – in pretty sad shape. The battery is a 6-volt unit that fits in the flip-open bottom, power was fed through the hinges.
The tiny hinges on the original tricorder prop just couldn’t take the beating of real-world use. They had wires soldered to them to feed power from the battery in the bottom compartment to the electronics in the top.
Close up of one of the original 3 we made. If you look closely at the “Alpha” lamp, you’ll see that it’s actually 4 rectangular LEDs – it’s all I had on hand at the time. Later I went to a larger, single LED module which looked much better. On the right, the screen was made with a 35mm plastic slide frame, so the Paramount team could position a regular 35mm color slide for whatever image they wanted.
I don’t have a battery right now, but you can make out the graphics we did for the screen on the later version. There were a couple of incandescent bulbs to backlight it. The cases, by the way, were always clear PETG vacuformed plastic (same stuff as plastic soda bottles)
The insides of the bottom compartment of the original tricorder, showing the battery holder
The bottom of the original tricorder. Labels were just adhesive-backed paper printed at a Massachusetts print shop. Note the dark gray metal filings sticking out at the bottom – more on that later
Inside the bottom compartment of the original tricorder. The silver thing in the bottom is a magnet. So that the tricorder would automatically turn on when the actors flipped it open, I designed it so there was a magnet in the bottom and a magnetic reed switch in the top – opening it would activate the switch and turn on the power without the actor having to do anything.
Closeup of the later tricorder. You can see the white rectangular viewscreen compartment (light bulbs inside) and the L-shaped circuit board
Velcro on the standard scanner
The little scanner (non-functional) fit into a pocket and was held in place by velcro.
Access panel in the back. The later series tricorders used smaller, custom surface-mount circuit boards so there was room for the battery to fit in the main body. We made custom battery holders by vacuforming styrene sheet over the top of the 6V battery so it press-fit in place. In this photo you can see the two surface-mount trimpots that let the crew adjust the blinking LED speed.
Back of the later version tricorder with access panel in place (gets held in place with two button-head cap screws)
This is the inside of one of the original 3 tricorders we made, I designed and built the circuit in 2 days with what I had on hand. It barely fit inside! a 556 chip provided two timing pulses and the two 4017’s ran the sequentia; LEDs. Huge discrete trimpots, transistors and resistors!
Another view of the later version tricorder.
The 4th revision of the tricorder driver circuit board. We usually made them in batches of 3, and I made little improvements on each batch. This was a surface-mount unit, all hand-soldered. 1992.
The other side of the tricorder revision 4 driver board