discharging caps

Sep 07, 2026 Last reply: 1 week ago 257 Replies

Were you working alone?

Just about the only workplace fatality I'm close to was a tech at Varian. Alone in the plant, he bypassed safety interlocks on a TWT supply test cage to speed up his job.

I've had to curtail my hours at places where bodies were unusually scarce. It made no sense to me - for a contractor to be sweating alone in a facility. Was nobody else aware of 'deadlines'?

Usually turned out to be a problem with morale. (. . and why contractors were there . . . )

RL

Not to feed the flames, but cloning hard drives, updating OS or transfering files should preserve that 'modified' date in Windows. Naming 'created' and 'modified' in this back-assward way was just another silly thing that MS did.

Zipped archives are also pretty good at preserving both.

I'm pretty 'lucky', in that I can associate most events within a

3 year window - having shifted locations with ~3 year intervals my emtire life (until the last 10). Associations with place and project do the nudging of memory.

RL

Yes, there is only room for one person at a time in my shed and I don't know anyone who would have the patience to stand and watch me for hours on end.

It sounds as though you had one body too many!

Wyhy does the exact date matter? You and Sloman aren't interested in the electronics, the resistor itself.

Silly old hens.

John Larkin Highland Tech Glen Canyon Design Center Lunatic Fringe Electronics

Only to the extent that you made a fuss about it in the first place.

I certainly am. Worrying about passive components, and how they can go wrong, has been a constant of my electronic career. I've also been worried about active components not doing what they should, and I've probably spent quite a lot longer worrying about that.

You want to pose as somebody who can design electronics, but wherever anybody gets interested in the details of your incomparable achievements you dismiss us as "silly old hens". It's not a great way of moving yourself up the pecking order.

Long-term, neons aren't reliable. They sputter away their own neon.

Varian was our biggest customer for many years, the NMR division.

Other technologies displaced NMR. The superconductive magnets were too expensive. Agilent bought Varian and killed the NMR operation.

I recommend a dead man's harness - sort of a leash on a dog-run - applying weight on the run configured to pull the main breaker for your bench.

It's a bit of a niusance, admittedly, but surprisingly easy to forget, when you go for a coffee break. . . . . .

. . . and it doesn't so much back you up, as make it safer for the next body that comes along to turn off the lights and to lock up, as the name implies.

RL

All this discussion about the date! It actually turned out to be helpful to me. I bought a really cheap camera to capture quick images that only needed to be recognizable, not even sharply focused (although they are in focus). Just 2 days ago -09/22/2026- I took a photo and printed it out. It's the first one I've printed, but it's the 17th photo from this camera (bought early this year). The other 16 are in files. The date on the printout is 08/15/2026. I didn't even know that the camera time stamped the images. The photos in files aren't a problem as the documentation is all dated, but the 17th is of a tomato plant a friend was asking about and the date would mislead her.

So - thanks for the "date" portion of this thread! BTW the printer has the correct date - I just have to go into settings on the camera.

Ed

I use my Samsung phone as a dumb telephone and as a camera. It's an amazingly good camera, actually four cameras. It always knows the date and time.

Well, it's a good RPN calculator too, a simulation of an HP42. Once you learn RPN, you can't go back.

That's way too much trouble. We just use interns.

Not always true. People other than John Larkin have managed it.

The local hospitals are still full of Magnetic Resonance Scanners. The Nuclear tag worried patients so it got dropped from the name.

If Varian lost money on the operation, they were probably doing something wrong. Super-conducting magnets are expensive, but other manufacturers still seem to be making money by building and selling the technology.

<snip>

What technologies _displaced_ NMR?

Jeroen Belleman

Not very helpful on ths occasion, the equipment had already been switched off for some time. Even if the 750v shock were from live equipment, if it had been across my chest I would be dead regardless of whether the breaker operated.

There is a big switch by the door marked "Master Switch" and an arrow pointing to "OFF".

Nothing has. MRI scans are still the preferred technology for many investigations. There are some interesting enhancements such as the use of hyperpolarised Xenon for lung imaging and function analysis.

That's indeed what I believed.

I see. Atoms with an odd number of protons and/or neutrons can resonate in a magnetic field and there are lots of applications of nuclear magnetic resonance other than medical imaging.

Jeroen Belleman

Indeed. I got taught about it as an undergraduate chemist - not about any imaging application, but because it could provide stuctural information about complicated organic chemical compounds.

My first encounter with the imaging application was at EMI Central Research just before I left (in 1979) when - as senior engineer - I got invited to a company presentation about a nuclear magnetic resonance imager they were planning to develop. I even asked why they weren't planning on using a super-conducting magnet and got told that they weren't suitable for generating a scanned magnetic field.

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