True Story No12


New uses for oscilloscopes

The 3-day week is fading from my memory now. Many readers will never even have heard of it!

At the time we were developing a computer in the corner of the laboratory.

As we'd only been given 9 months to think about it, design it, build three prototypes and to demonstrate a working system to the Australian Government it was hard enough without having only three days a week to contend with.

The restrictions were imposed just after the first prototype had been delivered to the lab.

Those in Industry may remember the hardships.

We were completely disconnected from the mains, or if deemed a special case, allowed only a limited amount of power for all but three days.

This meant that you couldn't work weekends or two days of the normal week.

That is unless one could invent a way of getting round the ban.

Our factory had been fitted with a special device installed at the mains input board.

This operated on our "off" days, and I believe in our case was set to deliver a current of 13 amps, any more than this and the device tripped and all power was removed.

The 13 amps was a figure agreed to cover the minimum security aspects which were agreed to be necessary for a "List X" site (whatever that was).

We had to have a company policeman permanently manning the foyer; or strictly speaking, there were three of them working in shifts.

This wasn't really enough because, during the period, someone broke in and emptied all the cigarette machines. Fortunately they didn't take any cryptographic equipment or secret documents for which they could have got a lot more than a few fags!

Being engineers we had worked out exactly how much power was available to us if we were to come in during the off days.

During the day we could operate the computer and one small oscilloscope.

An AVO, connected to the special mains lead that came several hundred feet from the front door and up the lift shaft, registered the number of amps of power we were using.

Ten Amps was our limit after about 6pm and 5 Amps was our limit during the day.

We worked in two shifts, 12am to 12pm and 12pm to 12am with an hours overlap so we could pass on details of progress, if any, to our colleagues. I worked the former shift with a fellow engineer and a couple of other engineers did the small hours.

It was very cold and snow lay on the ground outside.

After 6pm it got really cold in the lab.

The floor was bare concrete and too cold to stand on, so we had large pieces of fibre insulating board laid in front of the computer.

We had no heating at first but being resourceful we realised that the Tektronix valve oscilloscopes could be pressed into service for this purpose.

We arranged four of these, back-to-front, with their cooling fans blowing warm air over us.

The AVO read just under 10 Amps and things weren't too bad.

About 11pm, everything suddenly went dark.

The two anglepoise lamps went out, the computer display stopped flashing and the oscilloscope fans all stopped running.

We found our torches and went down to investigate.

We were on the fourth floor of the "old building", which had once been a margarine factory, and we made towards the front door of the "new building" which had been added in the 50s.

It took us about ten minutes to thread our way through the ghostly factory.

Finally, we met the security man who sheepishly owned up to having plugged in his ILLICIT electric kettle.

We went home.


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