Debugging my wife's alarm clock(ntietz.com)
ntietz.com
Debugging my wife's alarm clock
https://ntietz.com/blog/debugging-my-wifes-alarm-clock/
86 comments
> I think what this really suggests is that the transformer and power supply are providing multiple voltages. The +9V rail is broken, but the other rail (maybe +5V) for the LED display is fine.
There's a reference design in the LM8560N IC PDF that suggests that the additional secondary winding is only used to drive the display, and all other electronics is powered off the main rail.
The 10V cap is kaput and it can't filter the input power, 9V just acts as a filter (even a discharged one). The OP should replace the cap with a 16V one, because a 10V cap on a 9V rail just isn't right..
There's a reference design in the LM8560N IC PDF that suggests that the additional secondary winding is only used to drive the display, and all other electronics is powered off the main rail.
The 10V cap is kaput and it can't filter the input power, 9V just acts as a filter (even a discharged one). The OP should replace the cap with a 16V one, because a 10V cap on a 9V rail just isn't right..
Older wall clocks used synchronous motors which would literally move the second hand using the waveform from the A/C power. As loads on generators went up, the effective RPMs went down, causing downstream power to run at slightly slower than 60Hz. It was so heavily used that power stations used to run "fast" catch up on any cycles they fell behind at night so that there were exactly 86,400 in a 24h period to prevent clocks from running fast or slow.
Amusingly you'll see stories like this when power companies fail to maintain 60Hz on average over a day:
https://www.reddit.com/r/explainlikeimfive/comments/xscztp/e...
Amusingly you'll see stories like this when power companies fail to maintain 60Hz on average over a day:
https://www.reddit.com/r/explainlikeimfive/comments/xscztp/e...
I remember this happening in Belgium, where they detected it quite like a month after the fact.
Everybody got a letter in the mail (yes, snail mail!) explaining when they were going to run the system fast for a couple of hours to catch up.
Everybody got a letter in the mail (yes, snail mail!) explaining when they were going to run the system fast for a couple of hours to catch up.
It may not be used so much for clocks now, but you can still buy cheap timed power switches that use this method.
For example: https://www.argos.co.uk/product/5440524
For example: https://www.argos.co.uk/product/5440524
Wall clocks use batteries nowadays, but some clocks in devices permanently connected to mains power still use its frequency - e.g. my Siemens kitchen oven, which promptly was off when there were some synchronization issues in the EU grid a few years ago. You'd think that in an appliance that costs several hundred euros, a quartz crystal wouldn't really move the cost needle, but as long as they can get away with it most of the time, why spend more money?
A quartz crystal can still drift, while the AC frequency is being regulated to stay within a few seconds per year, for free (for the manufacturer).
These were very common in the last century and many continue to be used today: https://en.wikipedia.org/wiki/Telechron
Can I get a straw poll on people who still use a dedicated alarm clock?
I was born 1990±2, but I have always been an old soul. I've been waking up to BBC Radio 4 since I was a teenager.
My current one used to belong to my dad, it's a Sony dream machine with FM/AM, circa 2002.
I was born 1990±2, but I have always been an old soul. I've been waking up to BBC Radio 4 since I was a teenager.
My current one used to belong to my dad, it's a Sony dream machine with FM/AM, circa 2002.
I still use one, in part because I don't want to require my phone in my bedroom.
(Sometimes I have it in my bedroom sometimes not, just depends on where I happened to leave it when I go to bed. I do not look at the phone in bed).
I have had this particular alarm clock for literally 35 years. What I prize about it is the ability to set the alarm time with two big dials on front, instead of having to press next-next-next buttons on the bottom.
I do not know what I will do when it finally breaks.
I can't find a picture of it online, I'm not sure if I'm describing it in a way anyone understands, it does not seem to be a well-known alarm clock. It is one (of many) "Sony Dream Machine" models, but most don't have this feature. The front has two big dials side by side. The left one has 24 marked positions, for each of the 24 hours in the day, color-coded for day and night. the other on the right has 12 positions for the 60 minutes in 5 minute increments. So you can just turn one and turn the other to easily set the alarm to whatever time you like (well, whatever time on 5 minute increments!)
(Sometimes I have it in my bedroom sometimes not, just depends on where I happened to leave it when I go to bed. I do not look at the phone in bed).
I have had this particular alarm clock for literally 35 years. What I prize about it is the ability to set the alarm time with two big dials on front, instead of having to press next-next-next buttons on the bottom.
I do not know what I will do when it finally breaks.
I can't find a picture of it online, I'm not sure if I'm describing it in a way anyone understands, it does not seem to be a well-known alarm clock. It is one (of many) "Sony Dream Machine" models, but most don't have this feature. The front has two big dials side by side. The left one has 24 marked positions, for each of the 24 hours in the day, color-coded for day and night. the other on the right has 12 positions for the 60 minutes in 5 minute increments. So you can just turn one and turn the other to easily set the alarm to whatever time you like (well, whatever time on 5 minute increments!)
Could you take and upload a picture of your alarm clock? You have made it sound very intriguing.
Here ya go!
https://ibb.co/KrkdqMg
https://ibb.co/KrkdqMg
Is it similar to this model?
https://www.radiomuseum.org/r/sony_dream_machine_ez_4.html
I've never had one - I was just also curious, so I scrolled through more Dream Machine images than I should have.
https://www.radiomuseum.org/r/sony_dream_machine_ez_4.html
I've never had one - I was just also curious, so I scrolled through more Dream Machine images than I should have.
Ha, that's interesting, good find! It is similar, but mine doesn't have the (faux?) wood framing and doesn't look quite as much like it's from an alternate timeline!
i would have thought the picture you found was from the 70s or something, but it says circa 1990 same as mine, who knows!
Here's a photo from right now of mine, still doing it's job continuously since circa 1990:
https://ibb.co/KrkdqMg
Mine also has "Power Back Up for Clock (9V)" which is a nice feature. With a life 9V battery, if the power goes out, it doesn't show the time and won't sound the alarm, but it keeps the time, so when the power goes back on it still has good time, and your alarm will still go off. For an intermittent power interruption in the middle of the night.
It occurs to me that some people have never actually experienced an old digital clock, but the more typical way to set the alarm (or time) was two buttons on the BOTTOM of the thing, one labelled "hour" one labelled "minute", and you had to pick up the device and press or hold each button to increment that portion of the time: 9, 10, 11, 12, 1, 2, 3, etc. Truly terrible UX! But universal for a couple decades! In my opinion the ones above were really an innovation! Which never caught on (probably were patented) before the decline of non-computerized digital alarm clocks.
i would have thought the picture you found was from the 70s or something, but it says circa 1990 same as mine, who knows!
Here's a photo from right now of mine, still doing it's job continuously since circa 1990:
https://ibb.co/KrkdqMg
Mine also has "Power Back Up for Clock (9V)" which is a nice feature. With a life 9V battery, if the power goes out, it doesn't show the time and won't sound the alarm, but it keeps the time, so when the power goes back on it still has good time, and your alarm will still go off. For an intermittent power interruption in the middle of the night.
It occurs to me that some people have never actually experienced an old digital clock, but the more typical way to set the alarm (or time) was two buttons on the BOTTOM of the thing, one labelled "hour" one labelled "minute", and you had to pick up the device and press or hold each button to increment that portion of the time: 9, 10, 11, 12, 1, 2, 3, etc. Truly terrible UX! But universal for a couple decades! In my opinion the ones above were really an innovation! Which never caught on (probably were patented) before the decline of non-computerized digital alarm clocks.
Oh wow! That thing is fantastic! It is Sony doing what it does best; namely, making great consumer electronics.
I want one. Those big dials are super fun to use by all appearances too.
I want one. Those big dials are super fun to use by all appearances too.
I have used dedicated alarm clocks until the death of my parents, and then I have retired the clocks. One of them was a Sony clock/radio that might have been similar to yours, which I had given to my mother because it had very big digits, so she could see the time clearly from a long distance.
Another alarm clock had been built by my father, some 50 years ago, from medium-scale integration TTL circuits, before the apparition of dedicated integrated circuits for clocks. It still worked perfectly, and because it used a thermo-compensated quartz oscillator it had a much higher accuracy than the cheap quartz clocks or watches that can be bought now.
Since then, whenever I need an alarm or to know the time, I just use a smartphone or computer. I was born much earlier, so I have used dedicated alarm clocks for several decades, but I do not like to use superfluous things, so I no longer use dedicated alarm clocks (or wrist watches or TV sets etc.).
That does not mean that I do not like clocks, either mechanical or electronic. I like them, but I do no longer need them, so I like to examine them like I like to examine some ancient sword, which is beautiful, but for which I do not have any use in my daily life.
Another alarm clock had been built by my father, some 50 years ago, from medium-scale integration TTL circuits, before the apparition of dedicated integrated circuits for clocks. It still worked perfectly, and because it used a thermo-compensated quartz oscillator it had a much higher accuracy than the cheap quartz clocks or watches that can be bought now.
Since then, whenever I need an alarm or to know the time, I just use a smartphone or computer. I was born much earlier, so I have used dedicated alarm clocks for several decades, but I do not like to use superfluous things, so I no longer use dedicated alarm clocks (or wrist watches or TV sets etc.).
That does not mean that I do not like clocks, either mechanical or electronic. I like them, but I do no longer need them, so I like to examine them like I like to examine some ancient sword, which is beautiful, but for which I do not have any use in my daily life.
I do. Like many others, it's primarily so that I don't have to bring my phone into my room. I spend way too much time on my glowing pocket rectangle as it is.
It's some Sony radio clock, given to me by a relative 8-10 years ago, likely from Walmart or someplace similar. I have it set to the local classical station which is usually more pleasant to wake up to than the beeper. (Though occasionally, train horns in the distance will sound like trumpets, and I'll wake up and have to determine if it's a literal false alarm or not!)
One strange thing about this clock is, it seems to have a half-implemented support for dimming the display. You can get the display to dim by mashing the snooze bar, but once it's dim there's no going back unless you pull the plug and the backup battery. I saw a thread on a forum once about people discussing this odd behavior, but nobody seemed to have any explanation.
It's some Sony radio clock, given to me by a relative 8-10 years ago, likely from Walmart or someplace similar. I have it set to the local classical station which is usually more pleasant to wake up to than the beeper. (Though occasionally, train horns in the distance will sound like trumpets, and I'll wake up and have to determine if it's a literal false alarm or not!)
One strange thing about this clock is, it seems to have a half-implemented support for dimming the display. You can get the display to dim by mashing the snooze bar, but once it's dim there's no going back unless you pull the plug and the backup battery. I saw a thread on a forum once about people discussing this odd behavior, but nobody seemed to have any explanation.
I do.
My eyesight is so bad that, without my glasses, I cannot see the numbers on my iPhone, even when using the big number display in standby mode. About a decade ago I got a cheap no name thing off of Amazon with a 4” high LED display. That I can see!
My eyesight is so bad that, without my glasses, I cannot see the numbers on my iPhone, even when using the big number display in standby mode. About a decade ago I got a cheap no name thing off of Amazon with a 4” high LED display. That I can see!
Story time. It's Christmas, I'm 10yo, I've asked for and received a projection alarm clock from my parents.
I rushed to bed that night, set the clock, turned the lights off, got into bed, took off my glasses and... realised I couldn't see the projected time on the ceiling.
I rushed to bed that night, set the clock, turned the lights off, got into bed, took off my glasses and... realised I couldn't see the projected time on the ceiling.
I'm very nearsighted and the giant LED clock has been awesome.
I use a dedicated alarm clock.
Recently, I have built my own: <https://masysma.net/37/dcf77_vfd_raspi_clock.xhtml>
Before that (and now for redundancy, I think my own one still has some minor bugs), I used a cheap one by "OK" <https://www.mediamarkt.de/de/product/_ok-ocr-310-2172968.htm...>.
I don't like that I have to mash some tiny buttons to set the "OK" up and also to stop it. The LED that shows that the alarm is active is also hard to read for me. Hence I tried to improve upon this in my own design. I also found a solution to avoid the backup battery, but it is probably not what the "general public" would like to have either :)
Recently, I have built my own: <https://masysma.net/37/dcf77_vfd_raspi_clock.xhtml>
Before that (and now for redundancy, I think my own one still has some minor bugs), I used a cheap one by "OK" <https://www.mediamarkt.de/de/product/_ok-ocr-310-2172968.htm...>.
I don't like that I have to mash some tiny buttons to set the "OK" up and also to stop it. The LED that shows that the alarm is active is also hard to read for me. Hence I tried to improve upon this in my own design. I also found a solution to avoid the backup battery, but it is probably not what the "general public" would like to have either :)
Weirdly Nintendo released an alarm clock this month:
https://www.nintendo.com/us/store/products/nintendo-sound-cl...
Seems a strange thing to do in 2024.
https://www.nintendo.com/us/store/products/nintendo-sound-cl...
Seems a strange thing to do in 2024.
[deleted]
> Nintendo Switch Online required
So it's an alarm clock that checks your subscription is still active before waking you up. Welcome to the future. I hope AWS doesn't go down around 6:45am.
So it's an alarm clock that checks your subscription is still active before waking you up. Welcome to the future. I hope AWS doesn't go down around 6:45am.
No. It's just a pre-sale for members. From below: "For a limited time*, paid Nintendo Switch Online members in the United States and Canada can purchase Alarmo online via the My Nintendo Store before it is available to purchase by the general public."
I think the subscription is just required for the pre-sale before general sale. I really hope you're wrong about the sub being required for the damn thing to work, but it would not surprise me.
Born in 1983. I do, because I don't want my smartphone in the bedroom and I have more trust in a more trivial device. I got a Wake up light by Philips I wouldn't switch for a phone, and a very small Casio pocket clock when I travel. This device is LOUD and I love it ;)
You should have 3 copies of your data, on 2 different mediums, at least 1 one in a different location.
I strongly believe that in the same way you should have at least 2 alarm clocks, one of which is of a different type. I strongly believe that you should use your phone and a dedicated alarm clock. Apple has released bugs that caused the alarm clock not to run, or do so at a wrong time. Likewise it is always possible for your normal alarm clock to lose power or run out of battery.
Having both failures on the same day is a lot less likely.
I strongly believe that in the same way you should have at least 2 alarm clocks, one of which is of a different type. I strongly believe that you should use your phone and a dedicated alarm clock. Apple has released bugs that caused the alarm clock not to run, or do so at a wrong time. Likewise it is always possible for your normal alarm clock to lose power or run out of battery.
Having both failures on the same day is a lot less likely.
I do set a second alarm if I'm waking up for something particularly important - say a flight, but for a regular work day? I think one is good enough.
You don't need software bugs, if your power goes out at just the right time and the phone doesn't have enough charge to last you through the night, there goes your precious alarm. Same if you e.g. don't fully push the charging plug in.
Ask me how I know.
Ask me how I know.
> I strongly believe that in the same way you should have at least 2 alarm clocks, one of which is of a different type
Very HN. And a redundant mode of transport to work, a backup fridge on a redundant power source.
I draw the line after spare coffee grinding and brewing facilities.
Very HN. And a redundant mode of transport to work, a backup fridge on a redundant power source.
I draw the line after spare coffee grinding and brewing facilities.
It's been only four days since a phone alarm would have let me sleep through giving a talk. Android rebooted, somehow got stuck in a reboot loop (I think), discharging faster than the crappy charger charged. Luckily jetlag worked in my favor for once...
So I'm late for work once. Who cares.
I've been trying to find one that isn't full of ESP chips or phone chargers for a while, or at least one with a nice flashable chipset. They seem pretty rare these days.
The first half of your comment implies a design from the 70s (which is my preference), but the second half contradicts that and is beyond my understanding. If you flashed an alarm clock, what would you make it do?
The aesthetics and functionality are key for me.
I like the 70s style, I don't like the invasive elements of modern tech. I do like them however when I have full control over them.
> If you flashed an alarm clock, what would you make it do?
No idea, but it might be fun to get it to pick a random global streaming radio station, keep its time in sync via NTP, set it remotely from another device, use it as a remote key for a safe or door, etc. When you control the tech, the limits are whatever you set.
I like the 70s style, I don't like the invasive elements of modern tech. I do like them however when I have full control over them.
> If you flashed an alarm clock, what would you make it do?
No idea, but it might be fun to get it to pick a random global streaming radio station, keep its time in sync via NTP, set it remotely from another device, use it as a remote key for a safe or door, etc. When you control the tech, the limits are whatever you set.
Not too hard to build your own. Lots of tutorials based on i.e. ESP32 chips, various blinky light options. Google "Adafruit clock" to get started.
Thank you. I'll take a look!
I've got a wake-up light, probably 10 years old by now. It's a dumb machine, no wifi or QI or anything, but it's got a leg up over "old-fashioned" alarm clocks; the clock is red lights and dimmable to "barely visible in daytime", it's a very adjustable light from just enough to not stumble to burning out retinas (and comfortable reading in-between), it's got a radio and builtin "gentle waking up sounds" that are actually pretty horrible because of the tinny speakers. But preferable over morning radio that's usually announcers laughing or terrible music.
Downsides: Very expensive, it stopped working at one point but I replaced the power adapter and it was fine, tinny speakers like I said, and its design is round and on a very narrow base so it'll topple whenever you smack its touch sensitive surface to snooze it.
Before that I had a traditional alarm clock with yellow letters, radio, the works, had that for like 20 years before replacing it. The letters on that were stupidly bright so we stuck an unused photo film in front of it with tape.
Downsides: Very expensive, it stopped working at one point but I replaced the power adapter and it was fine, tinny speakers like I said, and its design is round and on a very narrow base so it'll topple whenever you smack its touch sensitive surface to snooze it.
Before that I had a traditional alarm clock with yellow letters, radio, the works, had that for like 20 years before replacing it. The letters on that were stupidly bright so we stuck an unused photo film in front of it with tape.
We just went back to one. For a number of years we let a phone do this job.
Then on one super rough day, both my wife and I were just drained! We hit the bed and were gone, snoozing hard.
Well, neither of us managed to have a phone charged well enough to wake us up and so we just didn't! Kid late for school, late for work, late, late... total pig of a day.
I picked up a $10 clock almost exactly the same as our old one, which did not survive our last move.
Now it has a fresh 9V battery and is set a bit behind the phones. It is the backup.
And we both kind of like having it again. We get a time display at a glance and it does wake us up nicely without being brutal.
These things are simple tech, but useful, low hassle tech too.
Then on one super rough day, both my wife and I were just drained! We hit the bed and were gone, snoozing hard.
Well, neither of us managed to have a phone charged well enough to wake us up and so we just didn't! Kid late for school, late for work, late, late... total pig of a day.
I picked up a $10 clock almost exactly the same as our old one, which did not survive our last move.
Now it has a fresh 9V battery and is set a bit behind the phones. It is the backup.
And we both kind of like having it again. We get a time display at a glance and it does wake us up nicely without being brutal.
These things are simple tech, but useful, low hassle tech too.
I do. I have a Muji one.
I don’t allow anything more complicated than that, a light and a book in the bedroom.
I don’t allow anything more complicated than that, a light and a book in the bedroom.
I was born two years after you and I'm always using an alarm clock, which saves me from worrying about my phone before going to bed (I just worry about batteries once a year instead). Though it's a simple beeping model from 15 years ago, I've never tried to use radio as an alarm clock.
I do! I still use my Ramos clock [0], which unfortunately isn't being made any more.
[0]: https://www.kickstarter.com/projects/2074185253/ramos-alarm-...
[0]: https://www.kickstarter.com/projects/2074185253/ramos-alarm-...
Me too! I even repaired it when the speaker failed. The creator was very helpful in telling me the model of speaker and giving me some tips for opening the thing.
I use one, a General Electric clock/radio unit from 1982. I bought it about a year ago so I could use my FM transmitter hooked up to my computer to send audio at specific times. It's just nice to have a dedicated device sometimes.
I do! Bought one at Ikea for 5€.
I use one because the sound on my android refuses to work (I am pretty sure it's a software bug, not a hardware failure, but i have no proof).since otherwise, the phone works correctly, i am not replacing it..
I use one because the sound on my android refuses to work (I am pretty sure it's a software bug, not a hardware failure, but i have no proof).since otherwise, the phone works correctly, i am not replacing it..
I went out of my way to buy an old Sanyo radio alarm clock so that I don't have to rely on my phone or keep it on my bed side table. The neat flip digit display is a bonus.
One dial to set the time, another to set the alarm.
One dial to set the time, another to set the alarm.
I have a handful of Realistic Chronomatic clock radios scattered about the house, including one at my bedside. The LED digits are large, and the alarms are loud - basically, exactly what I want in an alarm clock.
My wife uses a Radio Shack alarm clock that looks nearly identical to the one in this post. It broke recently and I fixed it by removing about 3 inches of the power cord where it attaches to the transformer.
I have since I had to switch to an iPhone for a new job about 9mo ago.
Someone in their design team decided alarms are optional and that sometimes they should just go off silently for reasons.
Utterly stupid feature I didn’t have time to figure out so back to a real alarm clock for waking up on days it’s important to do so.
Whoever decided to make alarms “adaptive” at Apple must have never had a real actual honest job in their life. Utterly infuriating.
Someone in their design team decided alarms are optional and that sometimes they should just go off silently for reasons.
Utterly stupid feature I didn’t have time to figure out so back to a real alarm clock for waking up on days it’s important to do so.
Whoever decided to make alarms “adaptive” at Apple must have never had a real actual honest job in their life. Utterly infuriating.
Yes, lots of times I have to double check: "Hey Siri, turn off the music in 1hr" => Timer => "StopMusic()"
...but then if you re-use that timer (accidentally) it will be "sticky" to stop playing instead of chiming.
Super frustrating! For as good as Apple's UX can be, they have some really bone-headed behaviors and designs in their core apps.
...but then if you re-use that timer (accidentally) it will be "sticky" to stop playing instead of chiming.
Super frustrating! For as good as Apple's UX can be, they have some really bone-headed behaviors and designs in their core apps.
Good riddance!
I never had the patentice to fuss with actually setting the alarm using the irritating multiple-mode/single-button controls and extra layer of complexity of multiple alarms, alarms for weekends, and whether you want a pre-selected radio station to play rather than the buzzer. To make it worse, when I did wake up groggy to the alarm I invariably hit the largest button to make it stop-- snooze, only to be further irritated when it would go off again as I was having breakfast.
I never had the patentice to fuss with actually setting the alarm using the irritating multiple-mode/single-button controls and extra layer of complexity of multiple alarms, alarms for weekends, and whether you want a pre-selected radio station to play rather than the buzzer. To make it worse, when I did wake up groggy to the alarm I invariably hit the largest button to make it stop-- snooze, only to be further irritated when it would go off again as I was having breakfast.
I didn't check the date on mine... but also a Sony Dream Machine. Probably same or similar vintage.
Update 10/27: A few readers have pointed out to me that it's likely a bad capacitor, which cap it is, and how to test that and/or fix it!
When troubleshooting old electronics, rule #1 is "check the caps". Electrolytic capacitors are the most common failure item in solid-state devices. This alarm clock predates the infamous capacitor plague but the finite and somewhat short lifespan of electrolytics has been known since their invention.
When troubleshooting old electronics, rule #1 is "check the caps". Electrolytic capacitors are the most common failure item in solid-state devices. This alarm clock predates the infamous capacitor plague but the finite and somewhat short lifespan of electrolytics has been known since their invention.
> which cap it is
One of my led wall lamp died. I opened the driver/transformer and has a very suspictious capacitor with a curved top.
Anyway, I just bought a $3 driver replacement in front of my home. (I'm bad at soldering, so I'd probably need a whole afternoon to try to fix it).
One of my led wall lamp died. I opened the driver/transformer and has a very suspictious capacitor with a curved top.
Anyway, I just bought a $3 driver replacement in front of my home. (I'm bad at soldering, so I'd probably need a whole afternoon to try to fix it).
Weirdly I ran into something similar many years ago. I took a similar alarm clock and hacked it to connect it the alarm signal to a stereo system with two 12 inch subwoofers. It was very very very loud. Neighbors could hear it a street over.
Anyhow, I had to update how it powered the internal speaker (which I was taping into) because it was a little bit too much and the thing would reset.
I’d go into more details but it was trashed and it’s been about 20 years since …
Anyhow, I had to update how it powered the internal speaker (which I was taping into) because it was a little bit too much and the thing would reset.
I’d go into more details but it was trashed and it’s been about 20 years since …
I'd love an alarm clock that can replicate the sounds of my teenage youth via playing classics such as "Extreme Mario Dubstep - Yoshi Bass Drop (Womp Womp Edition Remix)"
That shouldn’t be too hard these days. You can go the expensive route and use a raspberry pi but I know you can use something simpler. You can def do it for cheaper but an RPi does allow you internet connectivity and a buttload of other possible automations. Hell, add a zwave adapter and you can have the alarm flash your smart lights, and more!
I had one of these clocks in the past. I remember the clock working without a battery at all. The battery is only necessary if you want to unplug the clock and move it somewhere else without having to reprogram the time.
Or if the power goes out. Where I live, there are at least several outages per year.
Most places in the world that are slightly more exposed to weather than average run the risk of power outages. That'll be anywhere from Norway to Texas to Australia. In other parts of the world blackouts may be enriched by lack of grid capacity or incompetence.
> Most places in the world that are slightly more exposed to weather than average run the risk of power outages
Heavily depends on how exposed the infrastructure is, I'd say. I currently live in Spain and been experiencing way more power outages than in Sweden, where I was born and raised, even though the weather is much more extreme in Sweden. Main difference, as far as I can tell, is that Sweden mostly digs trenches for all sorts of cables and infrastructure, while Spain tends to (still) hang cables in the air and on the outside of walls. I still get my fiber from a cable that comes hanging down from the front-side balcony of my flat here in Barcelona, and that's the official installation from my ISP.
Heavily depends on how exposed the infrastructure is, I'd say. I currently live in Spain and been experiencing way more power outages than in Sweden, where I was born and raised, even though the weather is much more extreme in Sweden. Main difference, as far as I can tell, is that Sweden mostly digs trenches for all sorts of cables and infrastructure, while Spain tends to (still) hang cables in the air and on the outside of walls. I still get my fiber from a cable that comes hanging down from the front-side balcony of my flat here in Barcelona, and that's the official installation from my ISP.
I had the same experience when I lived in Germany back in the 80/90s. All the infrastructure was underground so the only time we had a power outage was when someone was digging and hit the line. I always bring this up now days living in Georgia where a strong wind can knock out power for a few hours.
It is very annoying because a PC motherboard using a coin-cell battery to maintain the clock can often go years without changing the battery (yes I know many of them will eventually leak but it can take decades).
There's also a US-wide time signal on WWV/WWVB - WWVB having a very simple binary-coded decimal time signal at 35 bits per minute.
Alarm clocks could dispense with the battery entirely by using non-volatile storage for the settings and alarms then using the WWVB signal to set the time. Upon resumption of power it could easily configure itself with no user interaction required.
Ironically my old alarm clock from the very early 2000s supported WWVB (with a physical switch for local time zone) but it still used non-volatile RAM for the alarm so upon losing power it would come back, get the correct time within a few minutes, but completely lose all alarms. Infuriating then and now.
There's also a US-wide time signal on WWV/WWVB - WWVB having a very simple binary-coded decimal time signal at 35 bits per minute.
Alarm clocks could dispense with the battery entirely by using non-volatile storage for the settings and alarms then using the WWVB signal to set the time. Upon resumption of power it could easily configure itself with no user interaction required.
Ironically my old alarm clock from the very early 2000s supported WWVB (with a physical switch for local time zone) but it still used non-volatile RAM for the alarm so upon losing power it would come back, get the correct time within a few minutes, but completely lose all alarms. Infuriating then and now.
I've got a label printer that uses a battery because it needs more current than (pre-pd) USB, but needing a battery when you also have AC seems a poor design. Especially a non rechargeable one.
I am not sure I have ever owned more than one desktop alarm clock, but I have used a few, and in my experience by the time a real power failure occurs the 9v backup batteries have drained to the point that it resets anyway.
I have also lived in a country where blackouts quite rare, usually just local blackouts due to a tree hitting a powerline, so in any given year I wouldn't expect one.
I have also lived in a country where blackouts quite rare, usually just local blackouts due to a tree hitting a powerline, so in any given year I wouldn't expect one.
Probably the transformer is bad or maybe a cap dried up, so it's just barely running on wall power.
Caps dry out but transformers don’t go bad unless dropped or something like that.
Sometimes if they get to hot or following many many heating/cooling cycles the insulation varnish on the transformer windings starts to fail leading to short circuit issues.
The varnish can wear down, but yes likely a cap
This
That's intriguing! I was under the impression that the mains frequency varied, which is why mains hum is useful for dating recordings. It appears there is some drift (but why?), although they aim to keep the average stable over a certain period. The article states that the device primarily relies on mains frequency for timekeeping, using the crystal oscillator as a backup. I found that unexpected, though I'm not well-versed in either topic.
The mains frequency is literally how fast the generators in power plants are turning. If the load on the grid increases, those generators slow down slightly and more natural gas/coal/heat needs to be added to increase the frequency again. This whole process is quite complicated as not every plant can react in the same time. Some plants are always at 100% capacity, while others are dedicated to governing the frequency.
So there are small fluctuations, often between 0.2 Hz around the base frequency, but the average is very close to the theoretical 50/60 Hz. And for an alarm clock that is good enough.
So there are small fluctuations, often between 0.2 Hz around the base frequency, but the average is very close to the theoretical 50/60 Hz. And for an alarm clock that is good enough.
A while back, this happened in the US:
The North American Electric Reliability Corporation (NERC) discussed a proposed experiment that would relax frequency regulation requirements. https://www.nerc.com/pa/Stand/Project%2020101422%20Phase%202...
Was that made permanent, or reverted? I thought I've noticed the accuracy of my older line clock being worse... trending fast.
From https://en.wikipedia.org/wiki/Utility_frequency#US_regulatio...
The North American Electric Reliability Corporation (NERC) discussed a proposed experiment that would relax frequency regulation requirements. https://www.nerc.com/pa/Stand/Project%2020101422%20Phase%202...
Was that made permanent, or reverted? I thought I've noticed the accuracy of my older line clock being worse... trending fast.
From https://en.wikipedia.org/wiki/Utility_frequency#US_regulatio...
I had no idea that digital clocks time themselves by by measuring the mains frequency. And that this is an intended, albeit very minor, function of the power grid! It's amazing how things that provide only a tiny benefit to any individual but has an effect on such a massive scale that people actually sit down and spend time making it work.
"Over a decade old" is technically true, but probably an understatement, to me it looks like something from the 1980s or maybe 90s? Apparently it's old enough to not have "planned obsolescence" designed in...
Fascinating. I thought mains frequency was variable, which is why mains hum can be used to date recordings? It seems that there's some drift (why?) but they try to keep the average constant, over some window?
The article mentions the device prefers to use the mains frequency for timekeeping, using the crystal oscillator only as a fallback. I found this surprising, but I don't know much about either of those things.
The article mentions the device prefers to use the mains frequency for timekeeping, using the crystal oscillator only as a fallback. I found this surprising, but I don't know much about either of those things.
I am no expert but from what I read & remember: it can have fluctuations and lagging behind or leading "real" time but it gets corrected and synchronized back later
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I think what this really suggests is that the transformer and power supply are providing multiple voltages. The +9V rail is broken, but the other rail (maybe +5V) for the LED display is fine.
So the alarm chip and the alarm sounder is running only from the 9V battery. If the battery is weak, then the sudden power demand from sounding the alarm is too much, the voltage dips and the chip resets.