Having said that, they were all of the same basic design and layout, and easily recognisable by way of the Stylophone logo in the upper right hand corner of the 6" x 4" x 1.5" (approx.) body.

All were driven by a single 9v PP3 type battery, fitted inside the unit by removing the large rear cover, exposing the underside of the whole circuit board and it's components*.

* There was an exception to this design, which will be discussed later.

The basics are here that you will see on any Stylophone:

On/Off switch
Vibrato switch
Stylus fitted in its' holder
Bright and shiny keyboard!

The stylus fits nice and snug into its' resting position, with its' thin white wire folded neatly underneath. (If it is not folded correctly, the stylus will keep popping out).
This method in itself eventually brought about a problem, in that the repeated creasing and flexing of the lead could result in the outersheath of the wire splitting, or even more drastic, a completely broken wire. I have seen a few over the years where 'mom or dad' has done a quick repair job with the aid of a piece of sellotape.
It is fair to say that some models (or more precisely) the circuits and boards used over the years were far more reliable than others.
While a few of these components are near impossible to obtain now, other 'modern replacements' would need some modification of the circuit board to fit them.

(The Stylophone Sales Center at stylophone.com explain this a little further, where their sale stock is checked beforehand for precisely this eventuality).

The rear of the instrument casing houses a tuning device, which protrudes through a recessed hole in the casing, allowing the pitch to be adjusted if playing along with another instrument.
This is basically a variable resistor soldered directly to the circuit board.

This does the job very well indeed, with any variation in tone usually due to a dying battery, or more often than not - a dirty keyboard, and/or stylus.

The actual 'making' of a note is made by simply applying the stylus tip to the 'keyboard'. This contact completes the circuit, and plays the note of the segment touched by the stylus.
This keyboard is actually part of the one and only circuit board in the Stylophone. It's not that obvious at first glance, but if you remove the back cover and hold the unit up to a light, you will see the outline of the keys shining through the component side of the board.
With this set-up, on the white model shown previously, there are only 3 separate parts, (plus the case of course), to assemble:

Circuit board & Components
Speaker
Stylus

A small group of Stylophones including the 350S model, and Dubreq amplifier.

And its' that simplicity - born out of great design in the first place - that makes the Stylophone such a smashing little gizmo.

a common problem!

Basics

There were plain white ones, black and white ones, wood effect ones, wood effect with volume controls, plain keyboards, keyboards with spacers, and that's even before the actual circuits are considered!.

Instantly recognisable by the keyboard, the stylophone came in many guises through the years, from the late 60's up until the mid 70's.....