....and a magnet (somewhere not to nearby) for finding the blighter....
....and a magnet (somewhere not to nearby) for finding the blighter....
It flew like a bird from the tweezers' mandibles and pinged twice on the hard floor.
A sweep with a strong magnet failed to produce anything.
so . . . . I have reached out to the Mighty John for help.
I'm hoping they're not special screws, unique to the Quasar, and that general ones will fit.
I have managed to bodge the job by tightening the other screw and then simply putting the back on, although whether the terminal is now touching the inside of the case back I do not know. It is ticking away though!
Thanks to all posters (and Matt for linking to this thread)
Bloody fascinating to a tech minded Smiths fan who grew up down the road
Thanks for all the patient cataloguing, recording, surmising and piecing together
Ok, I think I can tell a consistent tale from start to finish. I'm not promising that it is correct in all the details, but it fits what we know so far.
I like poetry. One of the reasons I like it so much is that it is so constrained. There are arcane rules of rhythm and meter and so on. A good poem works around and through all the constraints on it to leave you with something that feels like changing anything would be a step away from perfection and the words on the page are all that they could ever have been.
I've said it many times before, but every watch is a compromise and, to a certain degree, like poetry, it is how well that a watch movement manages the compromises and constraints of being a watch that is the measure of its greatness.
The Smiths Quasar really has its work cut out. Not only does it have the usual constraints of the size of the case, but it also has another constraint: the size of the integrated circuit in 1974. The reason that early quartz went for low frequencies like 8190 is simple - they literally didn't have room for enough transistors to divide a larger number. By '74 the situation was improving, but not by much.
As if that isn't enough, the power of the battery also severely restricts how many transistors (and how rapidly they charge and discharge) the watch can have and also the ways that electrical energy can be converted to mechanical energy. So the other reason the very first quartz went for low frequencies was to save power. Smiths made a tactical decision to go the other way.
In base two, there probably isn't enough power to step down from a high frequency lenticular quartz without draining the battery too fast, even if there was enough space on the available integrated circuit. What is certain is that Smiths chose not to have a quartz that resonated in a multiple of two. However, had they wanted to they could have had 1,048,576 or 2,097,152. Omega in their ship's marine chronometer, rather than their wrist one, opted for the simple but large and comparatively power hungry 4,194,304hz. I'm not doing the maths for their 2,359,356hz wrist chronometer! E
But I have for the Smiths: I think Smiths solved the problem by starting with as large a division as was practically possible. There are only four prime numbers below eleven - 2,3,5 and 7 and, for a variety of practical reasons, it's almost certain these are the numbers Smiths would have worked with.
So here's my idea of how the Quasar works.
When a battery is first inserted and the crown pushed in, an oscillator circuit on the integrated circuit will begin to, well, oscillate. This sends a fairly unstable and harmonic oscillating signal down one of the six 'legs' of the integrated circuit to one one of the two 'legs' attached to the quartz crystal. This will cause the quartz to vibrate. As the quartz is either a tuning fork:
https://www.youtube.com/watch?v=lxsM9Jv0OD8
or a disk not unlike a tingsha:
https://www.youtube.com/watch?time_c...ature=emb_logo
That is tuned to a pure note, then, as long as the signal is applied to the quartz it will chime, at a very high, pure, frequency, just as a tuning fork or tingsha would.
However, the quartz doesn't just give off sound (which we can't hear) it also releases an electric current as it vibrates. This pure oscillation returns to the integrated circuit (IC) down the other leg attached to the quartz crystal and up another of the six legs on the IC. This signal then goes to the divider circuit.
The signal oscillating at 1,548,288hz is then divided by 7 by the first dividing circuit giving 221,184.
This is divided by three by the next circuit giving 73,728
This is divided by three by the next circuit giving 24,576
This is divided by three by the next circuit giving 8,192
This is divided by two by the next circuit giving 4,096
This is divided by two by the next circuit giving 2,048
This is divided by two by the next circuit giving 1,024
This is divided by two by the next circuit giving 512
This is divided by two by the next circuit giving 256
This is divided by two by the next circuit giving 128
This is divided by two by the next circuit giving 64
This is divided by two by the next circuit giving 32
This is divided by two by the next circuit giving 16
This is divided by two by the next circuit giving 8
This is divided by two by the next circuit giving 4
This is divided by two by the next circuit giving 2
This is divided by two by the next circuit giving 1
This is divided by two by the next circuit giving .5
This signal goes through a final inverter circuit and a capacitor and powers the motor windings. There's nothing fancy, just four motor windings all connected together in series. With a square shaped sine wave, the motor moves on the 'tick' and stops on the 'tock', moving the motor by a quarter of a turn every second. This will then be geared up by X4 by the gear train to give a 1 hz tick and geared down by /60 and /60 for the minute and hour hands.
I think that catches it all, but I doubt it's perfect as I'm not an expert and I'm cobbling together bits and bobs from all over, for example, thanks is due to my almost childhood D1 BSA Bantam rectification circuit for helping me fumble my way through the inverter while ensuring that my toolkit still has a pack of blue Rizla in it! However, if my error shakes a real expert out of the woodwork then I'll be delighted
Any comments?
Last edited by M4tt; 18th February 2020 at 08:28.
Re: earlier thoughts about male researchers taking undue credit, there’s the nearer to home example of Jocelyn Bell Burnell and the discovery of the quasar itself https://medium.com/s/the-matilda-eff...t-5362bef36308
Last edited by OhDark30; 16th February 2020 at 11:41.
And just for the fun of it: the Omega 2.4:
2,359,296 /3
786,432 /2
393,216/2
196608/2
98304/2
49152/2
24576/2
12288/2
6144/2
3072/2
1536/2
768/2
384/2
192/2
96/2
48/2
24/2
12/2
6/2
3/3
1
It was worth doing the maths, but only because I hit on the 3 into 2 series almost immediately and the 3 at the end was obvious. I was kind of hoping that it was also a 7 division to start with...