Bank LED map

Bank map is simply visual indicator of port 32765. It can be build into ZX Spectrum 128k, ZX Spectrum +2 (grey case) or any other 128k machine where 74LS174 is used for port 32765.

Part list:
1 x 74LS138 or MH3205 (clone of LS138)
1 x 74LS04
4 x 470R resistor
2 x 100nF ceramic condensator
some wires
small universal board

I made this bank map without any board - I sticked LEDs and two sockets directly to +2 case, then I connected everything according schematics. There is first revision on pictures below, so the wiring is different from actual schematic, but function is same. I'm recommending to blacken contact spots on LEDs - e.g. put black tape between LEDs.


LEDs set-up
LEDs set-up.
LEDs underside
LEDs underside.
Logic placing
Logic placing.
Finished and working
Finished & working.


Boot & Spectrum command
Boot, then enter 48k mode.
Machined on bankmap.
Bank & mem together I
Bank & mem I.
Bank & mem together II
Bank & mem II.
Bank & mem together III
Bank & mem III.