I have seen that also in an Estyma LED clock, except that they'd clipped the ear horn off to open the path to the sounder a little more. I think it's actually a magnetic earpiece - the crystal ones of that age always seemed to me medical-pink with a clear ear horn.

I had a Radio Shack LED clock in the '80s or '90s (based on the clock module RS sold back in the day) that also used an earphone as the alarm sounder.

@@theelmonk Yes magnetic, and the transformer is part of the oscillator, as the chip outputs DC voltage only. Most common use for these chips was in stove ranges, to provide the clock for cooking, with the alarm output driving a loud buzzer or an oscillator, so you would set the alarm to the finish time, and be able to come back and check. On all the time, typically at full brightness, they did tend to cook the display, and also the electronics, seeing as it was typically right above the hot plates as well.

@@theelmonk Yup, the crystal ones also tended to be larger diameter

You could almost say it's _flapping in the wind._

I did an old 'hack' for this chip in my Heathkit years ago to summon the Seconds display and Time Hold functions.

@@FranLab cool! :) How long ago was that?

@@KeritechElectronicscheck out Fran's past videos for the Heathkit Seconds Display hack.

@@FranLab jut

Yes, that would be nice to hear the alarm. Maybe be she will make a follow up video to play the alarm ⏰️

Back in the late 1930's, a time when nearly all speakers used electromagnets (field coils) and all headphones were piezo crystals, Brush Mfg (maker of microphones and phono pickups) patented an 8" full range *piezo* speaker using a giant Rochelle Salt crystal. I don't know if it was ever actually put into production, but it sure would be interesting to hear one! Unfortunately, Rochelle salt crystals tend to crumble with age and exposure to moisture and vibration, so it is unlikely that any examples have survived (for those who are unfamiliar, modern piezo crystals are some sort of ceramic crystal, developed by Motorola). I read an article about this speaker online somewhere, posted with a portion of the patent info. I also discovered that some people grow Rochelle salt crystals in their kitchen simply for the fun of it and because of the sheer size and beauty that can be obtained.

Also used with the single transistor to make an oscillator, as the alarm and snooze outputs of the chip are simply logic levels, so you need the external oscillator, which is the transistor, the capacitors and the transformer, to make a audio oscillator, which then can drive the earpiece directly as well.

@@SeanBZA What is snooze output?

@@TheSimoc Don't know, but is on datasheet, probably just mutes the alarm or radio while snooze is active, so that the lights on the alarm side or radio backlight stay on to show snooze, or to light up a LED indicating it is in snooze mode.

@@SeanBZA Aah, something like that makes sense. Seemingly not used to feed any audio oscillator though. Which was the implication I got from your comment, and got me confused. Btw thanks for your detail about the oscillator anyway.

probably similar reasons custom lcds are cheap.

We've got a teny weeny VFD calculator at our local hackerspace. Real cuteness for the tube that displays numbers that are like 8 millimeters high :). And I got it to work.

I have such calculator now, it called "Elektronika MK 61". I often use it at school. It slightly modified, I've replaced batteries with Li-Ion cell and added little charge board. Now it can be charged with the original power adapter (not charger, cuz it was not designed to use any rechargeable power source in it). It takes to charge about 10 hours (5v, 0.1A), but I can charge it faster with onboard USB (cell and board are installed in battery compartment) (5v, 1A). Why I did this? The original metal parts just were fully corroded and some were crumbled, they were unrepairable. It not the only thing I’ve replaced in it. I also replaced a power switch (reason why previous owner (my math teacher) gave it to me) and power filter condensator. One more interesting fact about this calculator: in 2 times older, then me. When I searched for the problem of crashes, I’ve found the scheme of it. I was really surprised, when I found almost everything about debugging and repairing it. All waveforms, components, even size of some components and pinouts of CPUs. It was not service manual, it was regular thing like user guide. About the user manual: it 200 pages long. Yes, not 20, 200. It tells how to test the calculator, how works programing, how to program it and it contains some mathematical, physics, accounting problems. When I used it, I felt all that care about end user. When you buy it, you get full user guide, that tells everything from turning it on, to solving problems with the using programming, scheme of it, so you can repair it at yourself, power adapter and leather-like case. You understand that this product has only one goal - work, until it can't cover user’s requests. Even if it will be after 36 years.

My grand aunt used to work with a Casio Personal M-1 .... and always wondering the high pitch noise .... pretty packed inside, 2 boards. It is a mervel they got this calc running on 2 AA's with a pretty decent battery life.

@@Ender_P.K Sounds really interesting piece, reminding of the fond side of communist memories (Elektronika was a Soviet brand). DIY friendly user documentation was common, there were Soviet cars having pretty comprehensive instructions for mechanical repairs, as well as specs and electrical diagrams in their *user* manuals.

Some must be sacrificed in order that others may function.

That chip has the 50/60 hz option when a pin is either Vcc or Gnd, and like all products it would be made for a specific market.

If this was made for use in Japan it would also have a 100v input instead of 120.

Many late model VCRs had these too, only the displays were under w a red-tinted plastic cover, giving the digits a grey look.

The thing to remember about the snooze switch is that it's likely to take a lot of abuse from people who just woke up and are not happy. If you use a standard switch in that application, I guarantee you'll have warranty returns.

Those switches for the settings are pretty much standard parts, the right angle ones would have been special order items, but the straight ones, meant to be PCB mounted behind a panel, were off the shelf items used by the million in all radios as power and band selector, later on as radio or tape selector when cassette decks were put in, with a separate switch to provide power to the audio stage, along with a diode, from the cassette motor switch. All outputs from radio and tape were commoned on the amplifier, just which one got power determined what was heard.

Yeah, I LOVE the look of VFDs over LEDs or LCDs, they're so much nicer IMO. In case you're that way inclined you can get VFD modules which are drop-in replacements for HD44780 style LCDs.

VFDs were common in VCRs, there were many different display layouts produced. I have also seen a 10 digit calculator with VFD, it ate batteries real quick.

Same in my $4 smoke alarm.

It's right here - kzfaq.info/get/bejne/r8iYZKxprK-snYk.html

@@FranLab Thank you!

I have a GE SpaceSaver under-cabinet clock/radio that seems to have a very similar display as tube as well, though the AM/PM are a little less compressed. Its easy-clean touch pad controls, rectangular red LEDs, and green/blue VFD all still work perfectly.

A sign that they are being run with too much current - Many times they want to push the brightness, but it will limit the life of the display.

Yes. I pay extra for that.

Me too, but its getting harder to find old clocks where they're still in good condition.