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An inside look at a unique and very compact vacu-fluorescent display clock made by the same company that made the LUMITIME electro-mechanical clock I profiled last week. Enjoy!
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14 thoughts on “Lumitime: the next generation”
  1. Avataaar/Circle Created with python_avatars Pascal Nelson says:

    I had this exact clock, but labeled MFJ, for many years. I won it as a door prize at a hamfest. Ended up giving it to GoodWill during a move a few years back. Was still working perfectly.

  2. Avataaar/Circle Created with python_avatars Scott Grammer says:

    Hey, Fran. It's not a crystal earpiece. It's an 8-ohm magnetic earplug. Too small for crystal. The transformer makes it easy to drive. Parts Express still sells them for a buck and a half. See if you can't detect a magnetic field from it.

  3. Avataaar/Circle Created with python_avatars Keri Szafir says:

    Oh my, this VFD is just lovely! Definitely a thing of beauty and a joy for ever 🙂
    Got a Soviet VFD just like the one DiodeGoneWild recently posted a video of. It's kinda cute to see VFD clocks from both sides of the Iron Curtain appear on YT roughly in the same time. I'm kinda pressed with repairs and projects, held back by lack of energy and budget… but time allowing, I'll be making a multi-timezone clock with it, showing the time at different labs of the Global Electronics Hacker Network, haha :).

  4. Avataaar/Circle Created with python_avatars Pellervo Kaskinen says:

    Quite interesting! I built my still in use alarm clock from a kit in 1979. It is different in two ways. First it has red LEDs. Second, it has 24 hour display (my wiring choice). I remember wondering why it had 30 V power. And how it COULD have such high voltage. Turned out the chip was PMOS type and indeed rated for some over 30 V supply. I never have had any other PMOS chip in my hands.
    At some point the plastic case had twisted enough to pop open. I forced it back in shape and secured it with 1.5" wide transparent packing tape. At the same time I added a bigger capacitor to hold up the operation through at least 20 seconds of power drop. And unlike your clock, it has a crystal time base. 40+ years and it still runs fine. Although I have added a Radio Shack roof projection clock as well. That one has a VLF time sync, but only the 12 hour AM/PM operation without any option for 24 hour display mode.

  5. Avataaar/Circle Created with python_avatars Shaun Tremayne says:

    When I bought my parents first electronic radio alarm clock it was very funny. As set it for 6am and the alarm switched on with them waking to DJ saying "good morning" which they thought someone was in the room so both jump out of bed. So I got a fry up for breakfast that morning being up so early.

  6. Avataaar/Circle Created with python_avatars AnimationGoneWrong says:

    OMG… flakey little "micro switch" for the snooze… I think calling it a "switch" is being rather generous. LOL An earpiece for the "speaker"… single diode rectifier… wow… you'd swear it was made out of spare parts Tamura had laying around. But hey… it works!!! For DECADES! You can't argue with that kind of a design. Loved this video. ❤

  7. Avataaar/Circle Created with python_avatars Alan Canon says:

    The blue of the VFD reminded me of my TI Dataman arithmetic learning toy from 1977. It ran on a 9 V battery. I wonder if the VFD in it needed a higher voltage, and if so, how it was synthesized from 9V.

  8. Avataaar/Circle Created with python_avatars UpLateGeek says:

    Very cute! I bought an open frame VFD clock kit from China as a Christmas present for myself last year. I suspect it was quite a lot more expensive than this cute little clock would have been, adjusted for inflation. Plus you wouldn't have had to put it together yourself. But where's the fun in that?

  9. Avataaar/Circle Created with python_avatars BKD70 says:

    When I was young, I had a vac fluorescent alarm clock that I'm sure had the exact same display in it as your Lumitime there. The snooze button was touch sensitive rather than being a real button. The font on the AM/PM looked identical with that goofy looking "P" in the PM. I can't remember the brand of it, but after years and years and years the display finally got so dim you couldn't read it anymore unless the room was completely dark.

  10. Avataaar/Circle Created with python_avatars dentakuweb says:

    When I saw the hole on the bottom and saw the white plastic the first thing that came to mind was a cheesy little earpiece like that.
    It's a good way of making use of old stock that nobody was ever going to use for it's original purpose anymore.

  11. Avataaar/Circle Created with python_avatars mikeselectricstuff says:

    MM5316 – that brings back memories of when I worked in a local shop repairing warranty returns of clock radios & similar consumer stuff. There was another pin-compatible version, the MM5387, which could drive either VFDs or LEDs

  12. Avataaar/Circle Created with python_avatars Don Moore says:

    The MM5316 is what makes this so simple to construct. It was designed to run VFD and LCD displays. The displays I used run on only 22 volts, the MM5316 has a wide range of 8 to 29V. That display is not multiplexed.

    Notice that the transformer has two secondary winding pairs. One is low voltage AC (eg 6.3V) to run the filaments. I used a series resistor when I built mine in 1982 off the main winding, which is not the right way to do it. Later I added a LM4872 square wave generator to power the grids, and referenced it to ground – which is correct.

  13. Avataaar/Circle Created with python_avatars Kiki Lang says:

    Huh? That's what my wife's father's clock radio with and eight track player has. The switches are a little goofy. I think I'll oper her up, and fix it. I might take out the eightrack, and put in a CD player while I have it open…. Ha! I just watch your videos. I don't learn anything at all.

  14. Avataaar/Circle Created with python_avatars Ed Luke says:

    The transformer was there for impedance matching. To get alot of output from that piezo earpiece you need high voltage but not much current. The transistor is good at low impedance high current.

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