‘Prinz’ was the brandname used by the Dixons retail chain in the 1970s and ‘PrinzSound’, naturally enough, referred to their audio products. The name was found on conventional radios, hi-fi separates, etc. but today it seems to have become synonymous with ‘of their time’ items such as eight-track cartridge players and flappy digital clock radios like this one.
This was my bedside radio in the late 1970s and continued to be so until the early 1990s (by which time I was living on my own) when the clock motor expired. I don’t remember the crack on the right-hand side of the front panel – it’s possibly a consequence of languishing at the bottom of ‘that box of stuff which should really be thrown away’ for so many years – and, needless to say, the white casing would have been much whiter when new!
For anybody unfamiliar with this style of clock, it comprises two ‘drums’ with pivoted flaps attached to their circumferences. In each case, a ‘peg’ above the drum holds the frontmost flap in a vertical position, with the flap below it hanging vertically, thereby providing a display face of two flaps height. As the drum turns, the upper flap is pulled below the ‘peg’ and so falls to reveal the next. Therefore, each flap has the top half of one digit on one side and the bottom half of the next digit on the other. The right-hand drum has 60 flaps and turns at one revolution per hour, like the minute hand of a conventional clock; the left-hand drum, however, carries ‘am’ and ‘pm’ flaps and so completes one revolution every 24 hours. In order to bulk out the number of flaps on this drum, each hour is ‘doubled up’, thus giving a total of 48.
So far, so simple. Now here’s the clever bit. During the second half of each hour a ramped raised edge on the left-hand side of the ‘minutes’ drum pushes a ‘catch’ over the right-hand side of the upper hour flap. When this flap is pulled below the ‘peg’, which occurs at around xx:47, it moves just a short distance before being restrained by the ‘catch’. At the last minute (literally!) the raised edge of the drum ends abruptly and relinquishes its grip on the ‘catch’, which is maintained in position by a projection on the left-hand side of the 59/00 flap. And so, by this means, at the top of each hour both flaps fall in unison with a triumphant ‘splat’!
I’m not sure how the alarm mechanism works because it’s largely concealed by the alarm time indicator drum. There is, however, a protuding metal lever which holds a microswitch pressed in (the ‘normally closed’ contact is used, so it is ‘off’ in this position). At the set alarm time this lever drops back with a prominent ‘clunk’ and releases the microswitch. In practice it was usually this ‘clunk’ which woke you up rather than the radio itself! Following this, the lever is slowly returned to its original position by the rotation of the drums and ultimately presses the microswitch back in, giving an ‘on’ time of approximately one hour.
The clock section is completed by a mechanical sleep timer, driven by the clock motor, which can be wound up to 60 minutes and operates another microswitch wired in parallel with the aforementioned one, and a ‘spinny thing’ to indicate that the clock is working (or, as has been the case since the early 1990s, not working).
The radio section is a 9-transistor circuit running from a 6 volt supply and driving a 3 inch speaker, no different to what was found in contemporary lower-cost AM/FM portables. This design is quite competent on AM but not very sensitive on FM (the opposite to equivalent radios from the late 1970s onwards, where the use of dedicated integrated circuits gave vastly superior FM performance whilst the internal ferrite rod antenna was made as short and stubby (i.e. as cheaply) as possible – even where there was space for a longer one – so compromising AM sensitivity). A difference in volume between AM and FM is inherent; even today my local station which can be received with a length of wet string is still quieter than average strength AM signals. The dial is specific to the European market and has the AM (medium wave) band marked by the wavelength in metres, which must look rather strange to the younger generation today.
Whereas modern clock radios have a captive length of wire for an FM aerial, this one has a screw terminal to attach your own. In the early days I can well remember stringing long wire around my bedroom trying to get the best signal (I knew nothing about quarter-wave and half-wave lengths back then!). There is also a short piece of wire protruding from the back, attached to a ‘ground point’ in the radio circuit, for connecting to the screen of a coaxial downlead. I can vaguely remember my father fitting this but can’t recall if the proposed external aerial was ever implemented. In later years though, benefiting from being in an area with a generally stronger FM signal, the customary 3ft length of wire sufficed.
The clock is lit by a miniature neon lamp, and back in the late ’70s I can remember thinking that it would be cool if the radio dial was illuminated as well. It wasn’t until the 1980s, when the unit was opened up, did I discover the shattered remains of a ‘grain of wheat’ bulb intended for that very purpose! It must have been broken since manufacture – quality control at the Taiwanese factory where it was assembled was clearly non-existent. As I recall, a 12 volt bulb was fitted which gives adequate illumination with the 6V supply and has the advantage of an effectively infinite life (unlike the clock motor!). The difference it made was a revelation!
Controls are relatively few. The inner part of a dual-concentric knob on the left-hand side adjusts the clock and can only be turned in a clockwise direction – it goes without saying that this type of clock can’t be turned backwards! The outer part sets the alarm time and can only be turned anti-clockwise – the ratchet has three steps per hour, giving ‘on’ time options of approximately xx:17, xx:37 or xx:57. On the top surface can be found the aforementioned sleep timer plus switches for manual/auto and AM/FM. The tuning knob mirrors the clock/alarm set controls and behind this is the combined on/off and volume control. And behind that, not visible in the photograph, is an earphone socket which was used extensively in the earlier years, not for its intended purpose but for feeding both an external speaker and a cassette recorder!
The public affection for flappy display technology should not be underestimated; the nostalgia surrounding the erstwhile departure boards at airports and large railway stations is particularly noticeable. It’s still possible to buy clocks like this, usually uncased with the whole mechanism on view. As for me, I have no aversion to a ticking clock or the one-second pulse of a quartz movement when going to sleep, but how I ever managed with this Heath Robinson (or Rube Goldberg, for those on the other side of the Atlantic) contraption on my bedside table, with its periodic clicks and splats, is beyond my comprehension today!
The Technojunk Files 