Retro Challenge: In Which One Finds One's Towel.

The middle of the year is always a bad time for me entering the Retro Challenge. Between work, tax end-of-year, school holidays and (this year) an overseas conference, little time is left for Retro hacking.  As a result, it has taken me almost two weeks before actually getting anything done. Heck, I hadn't even selected my challenge.

A few weeks ago I bought a bunch of second hand retro gadgets from Trade Me, our local alternative to eBay. These turned up in a big box a week or so ago.

I went though the box, testing each of the units with a fresh set of batteries:

All but the Scrabble Sensor failed to power up at all, or exhibited faults.

I decided to try tackling the Speak & Spell first.  I decided to start by stripping it down. Disassembly was quickly and easily acheived by removing two Philips head screws from the bottom of the unit, and carfully pressing against four concealed tabs in the recesses at the top.  Construction is admirably solid.

There was an after-market ROM pack fitted, and when I removed this I found that the contacts were badly oxidised.  I cleaned it up as best I could, but decided to do further testing without the ROM fitted.

After judicious light application of some 1200 grit and a little Isopropyl Alcohol to the battery terminals, it sprang to life.

The keyboard was the next step.  Several keys were stuck, and many didn't repsond at all.  Overall, the keyboard felt quite fragile, so I decided to pop it out and have a look.  It didn't look good.

Carefully folding back the brittle black plastic sheet revealed the extent of the damage - extensive oxidation to both the copper switch domes and the wires to which they are supposed to connect:

At this point my wife suggested that dinner was almost ready, so she'd rather like to give the kitchen table back, so I quickly reassembled the unit and put it aside. Later that evening I did a bit of searching to see if anyone sold replacement keyboards for the Speak & Spell. I was unsuccessful in that search, but I did find this; a Z80A PIO based interface for controlling the Speak & Spell from a Sinclair ZX81. This looks like a challenge!