I have been collecting Amperex ZM-1000 tubes for the last few years and built a multiplexed display for them. I figured after 55 years it was time to start coding the Arduino Nano to drive them...
Here is a brief history featuring some of my clocks.
mediatechnology wrote: ↑Sat Oct 20, 2018 7:57 pm Some pics of recent vintage clock restorations.
Sometime between 1969 and 1970 I became interested in building a digital clock.
I was about 12 at the time and began sketching clock circuits using J-K flip flop dividers.
I am "clock boy."
My brother had some surplus RTL (resistor transistor logic) ICs mounted on circuit cards.
I was able to buy some Amperex ZM-1000 "Nixie" display tubes and some Fairchild BCD to Decimal HV driver ICs.
The ICs are mostly MC790P J-K flip flops, some MC789 inverters and a couple of misc gates.
All-in-all there are 19 ICs. (One is underneath on a Veroboard).
I wanted a small display so a multiconductor cable was used to link the "base" logic unit to the display head.
The display sat on my headboard with the clock stashed under the bed.
This was my first major electronics project.
Looking back on it almost 50 years later I realize the logic design was pretty solid.
The execution sucked - but hey - it was my first project and I was 12.
My Dad gets credit for the solid walnut case.
The clock display unit has three Amperex ZM-1000 "Nixie" displays. The hours "1" is a long neon.
The clock base unit uses 19 RTL (resistor transistor logic) ICs mounted on individual plug-in cards.
Most of the ICs are Motorola MC700-series RTL. A CMOS IC was installed "dead-bug" sometime in the 1980s due to failure.
Once I got a couple of Heathkit clocks I retired this unit.
It sat under my father's workbench for years absorbing sawdust, oil and dryer lint.
Sometime in the late 1980s or early 1990's I began phase one of the restoration replacing the 2N3055 regulator with a LM317.
An RTL IC failed and I had to cobble a dead-bug CMOS chip.
I later gave up because I realized it had become an unreliable pig.
The edgecards had became flakey and I didn't want to clean them and the receptacles.
The clock set in the garage and was later moved to the basement.
I decided, almost 50 years later to rescue it.
It took a can of Blue shower, a can of duster and a re-cap to bring it back to life.
Glad I did though.
The clock I restored before this one was an LED clock based on an MM5314.
The solid walnut case was one of my brother's from his "Time Machine" clock kit.
This particular MM5314 was so pretty I had to photograph it.
An early 1970's clock using scrounged LEDs and an MM5314. The "before" photo:
The restoration primarily involved replacing the awful Molex socket strips with a real machined-pin socket.
I had to scrounge for more LEDs since some had bad segments.
The LEDs were then soldered directly to the PC board.
So what does my 2018 clock look like?
The whole logic box is replaced by an Arduino Nano and a TinyRTC.
The display is single-wire WSM2812 RGB.
My how things have changed...
If I can find the schematics of the Ameperex RTL clock I'll post it.
I had to repair it from memory.
