Comment by remyp | Hacker News Reader

Comment by remyp | Hacker News Reader

This reminds me of a “bug” I found when working for a company that sells package lockers to apartment buildings. We used iPads for the user interface and had monitoring in place to alert us if an iPad went offline.

At only one location with two iPads one would go offline almost every day (but not every day) between 12pm and 1pm, for 10-20 minutes. Never the same time of day, and never the same length of time. It was always the same iPad, the other one on that network stayed online the entire time.

We replaced the iPad and the problem persisted. Finally I got fed up, put my phone on silent, ignored everything, and watched the Dropcam feed for the 2 hours near the usual time. Slowly I saw the sun light up the lockers, eventually shining on the iPad. Ten minutes later, after sitting in direct sunlight, it went offline. As the sun moved, the iPad went back in to shadow and came online on its own.

It was overheating and shutting itself off until it cooled down. The time changed because day lengths change, and the days it didn’t go offline were cloudy.

This reminds me of a story one of my college professors told about the days when he helped automate factories in the 80s. Every night, the control server hey installed would go offline around 1am then come back up a few minutes later. It was never the exact same time or duration. After a few days of diving through the code with no progress, one of his co-workers decided to stay up all night at the factory and just watch the server. Around 1am, the cleaning lady came in, unplugged the server and plugged in her vacuum.

That co-worker later went on to invent the Roomba. /s

There's a lot of permutations of this story including life support systems in hospitals I find them all apocryphal. The cleaning staff would notice right away if they just shut down a huge computer. Esp. in the 80s I doubt it even used the same outlet as a regular vacuum cleaner.

Some of them even had the mains wired directly into the case, so you couldn't unplug without an ax.

Correct, this is just an old urban legend

https://www.snopes.com/horrors/freakish/cleaner.asp

I too have heard this story, yet I had this exact problem at a k-8 school district, the staff would unplug the power to my t1 each night.

At one time I lived in an apartment building just outside of Seattle that had public retail space in the lobby. To allow residents and their visitors in after hours, a fancy touch screen was installed where you could enter an apartment number and it would phone the apartment where someone could then punch a number and unlock the door. Standard stuff.

Except that the touch screen could be activated by rain. In Seattle.

There was a small cowl over the apparatus to keep regular rain off, but if there was any wind at all, it was very easy for drops to be blown onto the screen and it would start phoning apartments in the middle of the night.

Amazingly, this was among the building's least troublesome faults.

Ha!

Many years ago I had an optical mouse that would act erratically in the afternoons (just wouldn't register movement). It seemed to be ok if I squeezed it while I was using it so I figured it was a connection somewhere. Eventually I realised that it was the afternoon sun streaming in through the plastic seam and somehow stopping the sensor.

Reminds me of a wireless mouse I had that would intermittently become stuttery, but would usually fix itself whilst I tried to troubleshoot. I eventually realised that my laptop was between the mouse and its receiver, and any higher than normal utilisation of WiFi would interrupt the signal. Moving the receiver to the other side of the laptop completely resolved the issue.

I lived in an apartment in Fl and during the month of August and into September, every afternoon my cable would cut out for several hours. Happened every year for the three years I was there and only during that part of the year. Could never get Comcast to get a tech out there during the correct time frame, but they had a box mounted on one wall and that time of year it got direct sunlight and I suspect heat was to blame.

I too had air temp heat related outages with Comcast. They finally dug up and replaced the equipment in the street.

I worked for a cable ISP helpdesk once and during a particularly hot summer I vividly remember an on/off outage where we'd be getting regular updates from the field guys along the lines of: "We opened the doors and it works now." and "It failed again but we got a fan from the neighbors and that seems to help!"

In the 90s I was working a summer job as a forest fire fighter, and one morning the radio kept constantly beeping on one channel. Nobody could figure it out until a couple of hours later we got a call about a fire on a hillside on the other side of town. It turned out there was a radio repeater on the hill and the fire had burned through its power line, so it was beeping to tell us it was running on batteries.

I setup several emergency call beacons at a college (push a button, and 911 is immediately dialed, and a big blue light on the pole strobes, to help police find you). After 2 weeks of random alerts for a single beacon, we eventually determined it was the sun hitting the face of the device, expanding the button a bit. Rotated the face of the device 90 degrees, and never had an issue again.

Just curious, but what was the ultimate "fix" you landed on? Did you simply move the machine out of the path of the sun? Add a visor or something to the screen or window? Add something to cool the device down when it overheats? Switch to a different device entirely?

We added a $25 sun shade/hood type thing around it and the problem went away. Made the screen easier to see as well!

Reminds me of a story an old coworker told me. He was working as a repair tech back in the days when computers had tape drives. He was called out to a military base where they had just moved their computer one floor up, because the tape drive kept glitching. It would start up fine but then error out some seconds later, seemingly at random. After staring at this for quite some time he finally decided to stretch his legs and wander to the window. And what did he see, but a radar antenna rotating around. The glitches happened every time the antenna was pointed in his direction. On the lower floor it was out of the beam so there wasn't any problem.

I was working in a place that used to be a food store. Talked to the former owner, they had a big problem with all the freezers turning off during the nights and when they came to work all food was unfrozen and had to be thrown away. Turns out the timer to the sign outside was connected wrong and also turned off the freezers in the night. I do understand them, the electricity wiring in that building was not fun to work with... The place had been several different stores, all adding to the cables and connections over the years.

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