This assembled kitset is offered “as-is” and is most probably only useful for parts (due to the age of the design) with the 12 button keypad of particular interest.
Back in the 1990’s, Dick Smith Electronics offered a wide variety of electronic kitsets, ranging from beginner level to more advanced – this kitset was one of the latter.
I liked to build (when I could see properly and hold a soldering iron without shaking!) kitsets like this “just for fun” and although it was a LONG time ago, I built this combination lock, checked that it worked and then put it away! The project never got any further off the ground.
Unfortunately I did not keep the schematics or any documentation so the new owner is “on their own” in this regard but I strongly suspect that the keypad is going to be the only item of any real interest anyway. The design is pretty rudimentary by today’s standards so if anyone was wanting to keep the kitset in it’s present fully assembled form, it would probably only be for museum purposes!
On with the description …

DICK SMITH ELECTRONICS – Electronic kitset
Function: Electronic compination lock
Kit ID: ZA-1450/1451 (keypad PCB)
Circa early 1990’s
Two separate PCB’s (single sided), one being the ‘brains’ and the other the electro-mechanical keypad.
12 keys and each key contact looks to be separately accessible.
2 extra connections for the RED 5mm LED near the keypad (indicating all systems are go when the correct code is entered)
Once the correct code has been entered, the miniature 9V relay on the electronics board operates and the SPDT contacts are accessible on the Green rear connector.
Coding is via hardwired links near where the keypad connects to the electronics board.
3x 4000 series IC’s are used, these being 4017, 4093 & 4518
PCB DIMENSIONS:
Keypad: 85mm x 50mm x 12mm height
Electronics: 105mm x 50mm x 25mm height (determined by the miniature relay)
Short interconnecting colour coded ribbon cable which can be folded back over itself, insulation placed between the two boards which then results in a nice ‘compact’ keypad unit. There are predrilled holes which allow for this type of installation.
COSMETIC CONDITION
USED Assembled
CLEAN
Actually only powered up once I think, to establish that it worked and then never used again. The keypad in particular is ‘like new’

Now packed into a sealed clear plastic packet to keep everything ‘dust free’ while waiting for a new owner