Scoot on over for a wheely tricky mystery with an electrifying solution
- Reference: 1634286613
- News link: https://www.theregister.co.uk/2021/10/15/on_call/
- Source link:
Today's story comes from "Kristian" (not his name) and takes us back to the era of punch cards, tape stations, and hard disks the size of washing machines.
Our hero was a travelling technician, blatting around the Nordic countries offering repair, support, and general technical hand-holding services for customers with deep enough pockets to afford the big iron of the time.
[2]
Some used a very advanced CAD/CAM system for textiles, which required relatively high-end HP minicomputers (likely something from the 16-bit 2100 series and its many derivates, which ran from the 1960s through to the 1990s).
[3]
[4]
"I had just installed a new system at a site that manufactured, among other things, bras," he told us.
The computer room itself was the very latest in modernity and style. "The flooring," explained Kristian, "was some new-fangled synthetic that was supposed to be conductive so as to guard against static electricity." The cabinets and consoles were custom crafted from metal. All very impressive, and probably expensive, stuff.
[5]
But all was not well at the site. The boss of the team was convinced that the mysterious beige and grey box had taken a distinct dislike to her. Every time she went to the main console (a terminal perched atop the computer and hard disk), the system would abruptly shut down.
The problem also only happened to her. The other users did not get the same treatment from HP's finest.
[6]Fatal Attraction: Lovely collection, really, but it does not belong anywhere near magnetic storage media
[7]Computer shuts down when foreman leaves the room: Ghost in the machine? Or an all-too-human bit of silliness?
[8]Check your bits: What to do when Unix decides to make a hash of your bill printouts
[9]Electron-to-joule conversion formulae? Cute. Welcome to the school of hard knocks
High-end lingerie not to be denied, a support call was placed: "The system was a male chauvinist," the complaint went, "and clearly hated her guts."
Our hero professed himself a bit confused. Other than in the fever dreams of movie makers, computers were not sentient and certainly did not take against specific users. This customer was, however, adamant and understandably very upset. So a call-out to the site was made to both unruffle feathers and get to the bottom of the problem.
Nothing was obviously wrong. Kristian watched other users come and go from the console. The team leader, however, had no such luck.
[10]
"As soon as the lady in question scoots over in the office chair and approaches the console terminal, system promptly shuts down!" he told us.
A mystery indeed.
A solvable mystery, however. "It did take me some trial and error to pin down what was happening," Kristian told us, "but I figured it out."
He opted for a simple demonstration. The room lights were turned off and the curtains drawn. He then sat himself down on the boss's chair and wheeled himself over to the metal desk with the console.
"Lo and behold," he said, "as soon as the chair was within a centimetre, a nice blue spark jumped from the chair to the desk, and the system promptly shuts down."
It transpired that the fancy chair used by the boss had plastic wheels, and the boss was the only one with a desk within "scooting distance" of the terminal. A single scoot would generate enough charge to upset the HP minicomputer.
"The floor was just false advertising," Kristian said.
Ever had a hardware failure that turned out to have nothing to with the hardware at all? Or staged your own Poirot-style denouement to demonstrate your cleverness? Of course you have. Send your story to [11]On Call . ®
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[6] https://www.theregister.com/2021/10/08/on_call/
[7] https://www.theregister.com/2021/10/01/on_call/
[8] https://www.theregister.com/2021/09/24/on_call/
[9] https://www.theregister.com/2021/09/17/on_call/
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It is a not so well known fact
that Wimshurst was inspired by pissing about on his roly chair in the office.
Makes a change...
OK, so how many were expecting it to be her own lingerie static rather than the office furniture and fittings?
Especially given the production output of the factory...
Paris, well for so many reasons...
I worked for a while with a company making mainly signal conditioning equipment - temperature transmitters, trip amplifiers, small scale signal multiplexers etc. They also sold a few thermocouple and resistance thermometer temperature sensing elements.
We had a customer return a resistance thermometer to us as "inaccurate and fluctuating".
Unlikely, we thought. A resistance thermometer is a coil or foil wire sensor that is 100 ohms # 0°C. 138.5 ohms @ 100°C 119.4 ohms @50°C. it inside a mineral support, inside a stainless steel tube which is closed at one end and has four leads coming out of t'other, sealed in with a dob of epoxy snot. The sensor slides into a fabricated pocket that as a big terminal chamber at the top, where the wires across the pant connect. Very simply, nothing to go wrong.
The office guys were scratching their heads. I had a decent amount of experience in the real world and asked what these sensors were monitoring. Turns out it was a cool, humid and generally damp application somewhere on board ship.
The leads coming out were insulated with glass fibre based sleeves (the alternative being PVC or PTFE). That was enough for me to suggest checking for any conductivity between sensing element and probe body. Loads of it.
The damp simply had gotten into the terminal enclosure of the thermowell and wicked down the insulation, obliterating the accuracy of the sensor.
Really simple for someone who's worked in the real world.
Snap!
We had a similar sensor but at 10k and made to specific overall dimensions and trailing leads etc. We ordered in batches of 200 for incorporation into a bigger machine. During assembly-tests, a number were found to be faulty: one side conducting to earth. Supplier QA was alerted and the problem resolved on new batches.
However, there were many others out in the field and despite internal checking, some of these were displaying intermittent failure. Returning a completed machine for rectification involved cranes, transport plus significant re-work. All in all very expensive for a relatively low-cost, minor component which in the past had been considered ultra-reliable. Since one side of the sensor was always 'grounded' within the control unit, the interim solution was to exchange the wires....
Yes, static is a thing
I remember a colleague and I standing in a police control room, rubbing each other with balloons.
Re: Yes, static is a thing
Oi, this is not that sort of a website!
Yes - I mentioned this before on here.
Back in the mid-late 90's Toshiba ventured into the desktop PC arena with some quite nice units (and as a digression I LOVED Toshiba laptops - so well built and performed better than the then top-range Compaq's and Dell's etc).
A lady called in that her monitor had gone pop one morning.
A replacement was duly sent out. A week later she called to say that the same thing had happened, so once again a replacement was sent out.
Another week passed...yep, same call comes in. This time, Toshiba instructed that they wanted an engineer to visit and watch what was happening as a pattern had been noted - the call came in mid-morning every Thurs (or might've been Friday), so the engineer was despatched with a new screen and instructions to the lady to ignore them and just do what she would normally do.
It turned out that she had a potted plant on top of the screen with no bowl or saucer underneath. Every Thurs morning she would water the plant and a couple of hours later, the water would find its way through the pot and drip into the screen.
When the screen was being replaced, she'd obviously moved everything off so no pot to be seen and just enough water through to cause the damage but not enough to spot obvious water ingress.
Apparently she'd done this for years but the old screen must've had vents in different places as it never happened on that.