Speccy ROM+Diag

I had a Spectrum on the way from the UK...  I knew it would need a new keyboard membrane - but would it otherwise be healthy?  Could I order a Steamcard Pro and have it arrive in time? No.

Could I design myself a card that met my needs and could be delivered in a week?  It turns out that indeed I could.

My minimum requirements:

• Works with the original 16K and 48K Spectrums.
• Support for standard 16K Spectrum ROMs, including popular diagnostics.
• A reset-switch and indicator LED.
• Indicator LEDs for the +5V, +9V, +12V and -5V rails.
• Pads (pins) for each expansion-port signal available for easy access with 'scope or multimeter probes.

I decided to support both 28 and 32-pin PROMs for a possible 64 ROM images and rotary switches to choose between them.

Not quite!  But I didn't do too badly:

• I made a couple of silly errors with the Silkscreen markings.
• The mysterious jumper blocks are overkill and some are possibly redundant.  It's also really hard to describe what they're supposed to do.
• It could use holes at the back for support 'feet' - it's a little floppy.

Still!  It does what it says on the tin and works perfectly for my purposes.

That's a good question.  If you are looking for a state-of-the-art super-duper ZX-Spectrum diagnostics cartridge, then get a SteamCard Pro.

If, however, you want a small, simple hardware project for your 16K or 48K Spectrum, then perhaps the Speccy ROM+Diag card isn't a bad place to start.

Check back very soon for links to the pcb-files (gerbers), the Bill of Materials and a detailed build-guide.