For the belt circuit prop that the GBs wear on their
belts, you need to replicate a 1980s SANYO ICC 808D or
a Minolta Minolcom calculator circuit board.
These things are rarer than rocking horse shit now, and go for
$$$$ when they appear on eBay (which is rarely)

Here is a screen shot of a movie belt gizmo
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Here is the Sanyo circuit board
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You will need 14mm capacitors, I got these from eBay
seller ellyexcess but you may have to do some Googling or searching on eBay as they are hard to find!
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Here are the correct size Nixie tubes from eBay seller
Nixiestore.
You want the IV-9 Numitron tubes. Or do a generic eBay search for "IV-9 Numitron" and they always come up.
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PDF of the circuit board and all the chips can be found HERE - all correctly sized, just print out and you're set! Courtesy of Jairus Whitley.
This is the underside of the circuit board,
flip this over in Photoshop so it's a mirror image, to
get it the right way round, resize the width to be 95mm
then print it out on photo paper using max dpi.
Here are all the dimensions - use these
to draw a paper template on graph paper, then use that
template to cut out a base board on some stiff plastic:
Max width of the board is 95.5mm
Max height of the board is 147.6mm
Overall width of the edge connector is 72.6mm centered
on board
Left edge connector is 44.9mm
Right edge connector is 24.7mm
Height of edge connector is 9.8mm
Side indents are 2.3mm deep
Side indents start about 49.3mm from the bottom (not including
the edge connector) and are about 40.9mm tall
The exposed glass part of the gas-discharge
displays is about 25.7mm tall and 10mm wide
The white chips are 23mm tall by 16.5mm
wide (excluding legs) Metal window cover ones are about
1m thick while the non windowed ones are 2mm They are
elevated off the board give or take 3mm
The black ICs are 20mm wide by 12mm in length
and 3.9mm tall, they are elevated off the board give or
take 1mm
The pillow shaped IC in the bottom right
is 30.6mm by 12.5 and 3.5mm thick...
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Here is my plastic one, sprayed a dark green.
And below is with the photo paper printout glued in place,
then coated with some varnish to keep it in place.

Looks convincing huh? ;o)
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Here are the Nixie tubes with the correct
colour wires - you have to buy the wire, strip off the
plastic cover, and slot it over the Nixie wires. There
are 2 black, 2 yellow, 1 green 1 white and 1 red, on each
Nixie
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For the black caps that run along the top
of the Nixies (see HERE),
use flat styrene and styrene tubing, available from model
shops

Measure the flat styrene so it's the same width as your
circuit board, then position the 8 circles evenly along
it
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Make this sloping shelf, also the width of the circuit
board

Then glue them together, prime, and spray black. This
will then glue onto the top of the circuit board - the
Nixies slot into the circles, and glue them to the sloping
base.
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Use the solder points on the photo of the circuit as
drilling guides for the Nixie wires - we had to drill
4 holes higher up though as the Nixie wires wouldn't reach
otherwise! Also use the photo solder points as guides
for the capacitors.

Click to enlarge - looking good now! Just have to make
the fake chips from Styrene and then drill more holes
and slot in fine brass bars for the chip "legs"
and then random other capacitors and things down the left
hand side.
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Using brass round wire about 1mm, holes were drilled
in the board and the wire bent into an elongated staple
shape, and pushed theu the holes then Araldited on the
rear.
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Then print out a scan of the white chips, glue to white
styrene, then Araldite on top of the brass wire.
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Black chips were mocked up in Photoshop then printed
on photo-paper and glued onto 3mm perspex. Random resistors
and capacitors also glued on. All done now!
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Smaller part of belt circuit - awaiting a couple of old
Chips then all done!!!
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You need to find a black tape measure holder like the one pictured HERE but make sure the dimensions are such that the board slots in snugly and is gripped in place.
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