While talking computers are old hat today, in 1978, a talking toy like the Speak and Spell was the height of novel tech. [Kevin] found a vintage one, but it didn’t work. It looked like someone had plugged in the wrong power adapter, leading to, undoubtedly, one or more unhappy children. There was some damage that suggests someone had already tried to repair it, but without success.

In addition to effecting the repair, [Kevin] took lots of pictures, so if you ever wanted to peek inside one of these, this is your chance. The case had no screws, just clips, although apparently some of the newer models did have some screws.

In addition to a sophisticated speech synthesizer, the gadget had a sophisticated power supply to drive the vacuum fluorescent display. The power supply board had a suspicious burn mark and a cracked TO-92 transistor.

[Kevin] found that someone had reversed a schematic for a similar power board used in a different version of the toy, but it was close enough. The simple switching power supply used a handful of bipolar transistors. The cracked transistor was one of a pair, so to be safe, both needed replacement. After all, the transistor failing either put a high load on the uncracked transistor or, perhaps, it cracked because the other transistor failed first.

Oddly, after that repair, the device would work with an AC adapter, but not with batteries. The battery voltage is a little lower, so with a little simulation and some changes in components, the device works again, even with weaker batteries. You can see the startup sequence on a scope in the video below.

If you want to explore Speak and Spells yourself, don’t miss the bibliography at the end of the post. Some people swear by these toys. Other people make them swear. If you’d rather build something new than repair, there’s help for you.