Just for the Heathkit Fans! Yes, this GC-1107 Digital Clock was my very first electronic build from waaaaay back - and I have found a cool hack/mod to make the first of my projects even better than it ever was.
For further reading check out my blog Heathkit catalog posts:
Highlights of the 1979 Heathkit Catalog - http://www.frantone.com/designwritings/1979HeathkitCatalog/heathkit_catalog_1979.html
Highlights of the 1984 Heathkit Catalog - http://www.frantone.com/Heathkit_Catalog/heathkit_catalog_1984.html
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For further reading check out my blog Heathkit catalog posts:
Highlights of the 1979 Heathkit Catalog - http://www.frantone.com/designwritings/1979HeathkitCatalog/heathkit_catalog_1979.html
Highlights of the 1984 Heathkit Catalog - http://www.frantone.com/Heathkit_Catalog/heathkit_catalog_1984.html
Join Team FranLab!!!! Become a patron and help support my YouTube Channel on Patreon: http://www.patreon.com/frantone
- Music by Fran Blanche -
Frantone on Facebook - https://www.facebook.com/frantone/
Fran on Twitter - https://twitter.com/contourcorsets
Fran's Science Blog - http://www.frantone.com/designwritings/design_writings.html
FranArt Website - http://www.contourcorsets.com
The clock chip is a PMOS chip; NTE still stocks it. My chip went wonky on me and I was able to replace the chip. I have to find the paperwork, but it can be chased down.
EDIT: The chip is part number NTE2061. I had one of the early versions and thus early spins of this chip. The ones I bought in the mid 201x's had many features fixed, including the spurious "*HONK*" from the alarm if the alarm date went by and the alarm was off. (I did not have that 3 pole switch for the back of mine with the speaker cut-out. In any event, that fix is still available.
Ok Fran, figure this one out. Made test changes on the bench before actually doing the retrofit. Soldered a wire to pin 32 and toggled on and off of the Red(AA) and it seemed to work as you demonstrated. Unplugged the clock and performed the operation as you did but when I plugged the clock back in it was STUCK in the minute-second mode(the switch was in the off state). I removed the wires from the switch and it was still stuck. Still puzzled I further found that if I tied Pin-32 to GND it would return to normal but as soon as that wire was lifted off GND, it would revert to minute-second mode. I cleaned around pins of IC-1 but its still stuck. ANY IDEAS? Did IC-1 flake out? UPDATE: Also noticed that a display segment would occasional illuminate when it shouldn't so decided to get IC-1 via ebay and lo-and-behold, not only did it fix the stuck hour-minutes situation but the segment situation is gone and upon firing it up the pm indicator now flashes indicating there was a power failure which it hasn't done in years.
I Love Your Intro, Keep it…
Love seeing the old Heathkit catalogs – my wife and I married in 1978, and she enjoyed building the alarm clock kit with me (GC-1107) which still works great almost 45 years now. We also built the doorbell kit (TD-1069), which served for years until the audio quality broke down – I didn't think at the time to re-cap it. My idea, which I hoped was the subject of your video is to update the clock with an "Arduino" ESP8266 so that it gets the time signal from the Internet wifi. The only downside of the clock all these years has been having to reset it after our (frequent) power outages!
Thank you for this video. I wish I could learn how to do this.
I believe these mods are related to one of their other clocks (GC-1092) which has 6 digits, and the functions you’ve added here. On that clock, I mod’d it to show the alarm set time when touching the top alarm-stop bar. I sure loved HeathKits, I’ve built more then three dozen of ‘em.
I have one of those GC-1106 clocks that I got fully assembled from a thrift store like 15 years ago. I've used it ever since because I love the green fluorescent display. I've never had it apart but knowing it was a kit I think I might, even just to find out what's rattling around inside.
Lot better than the snooze button
I assembled one of these clocks back in the day! Used it for many years but the display went bad. My folks lived about 5 miles from the Heathkit factory and they had a showroom I visited frequently. Really enjoyed the video, Thanks for sharing!
This is long after you posted this, but a neat time "hack" is the fact that any GPS receiver will receive GMT time/date long before it actually has anywhere near enough satellites to get a proper fix, meaning that even in locations that have lots of cover or poor lines of sight (indoors), you can get a time/date pretty easily and GPS is essentially "atomic time". 😉
You just need the most basic $5.00 Chinese GPS module with antenna and a $2.00 Arduino Pro Micro.
Many comments on that resistor – but I should mention that I modified the dimmer circuit some time ago to run at just a fraction of the default brightness to save the phosphors, and since then the filaments just don't pull the kind of current to heat up the resistor anymore. The resistor stays pretty cool now, and the burn in is minimized. ☺