Interesting article - I've just partially resurrected a "Pro" Stylophone (Model 350s) for a client of mine - it was horribly corroded internally (battery leakage), and also in need of a decent PSU (as the default 18v supply from two 9v batteries on this model drastically reduces the lifespan of some of the components) running at about 15v.<p>Unfortunately the keyboard and resistor ladder were too badly corroded to make it economically viable to fix it (client didn't want to pay - it would have taken me at least half a day to do it properly, and it's not really worth that when you can get a recon one for £199), so only half the keyboard works well (or as well as a stylophone ever did). The 350s added some interesting extras to the original stylophone - different waveforms (described with names of real instruments which is stretching it a bit), a 'reiteration' stylus (which produced a rhythmic on/off of the note selected with it), and an optical sensor for Wah-Wah or vibrato intensity. I'd imagine that properly built it would have been an interesting machine, although I don't know where it sat price-wise against 'real' synthesizers of the day. The owner has had a few hit songs, and it was interesting to realise that it was the actual instrument I was repairing that featured on one of his hits!<p>Pity that the whole thing is somewhat tainted with the association with Rolf Harris, like so many things from my youth in the 70s in the UK.