You can read more about these clocks here.

Other Heathkit clocks, like the GC-1000 Most Accurate Clock, the GC-1195, GC-1197, and so on would also be of interest.

• GC-1000
  I have a GC-1000 that needs a replacement pre-programmed Mostek 3870 microprocessor, Heathkit part number 444-293-1 (sometimes noted as 444-293-01). Does anyone have any spares of this part?

• GC-1005
  The GC-1005 uses three Beckman SP-352 two-digit gas discharge displays. Click here for more information about how these displays decay over time.

  The clock chip is a Mostek MK5017 PAA (there are variants of this IC, including MK5017AA, MK5017P and MK5017A). This is a 24-pin dual in-line package (DIP), typically white ceramic with gold-plated pins.
  Click here for more information on the chip. This is Heathkit part number 443-601.

  Spare SP352 displays and MK 5017 clock chips are also of interest, as well as CS-352 (the sockets for the displays) and Dionics chips like the DI-770N and DI-297N (the DI-770 (DI770N) and DI-297 (DI297N) are driver chips for Panaplex displays like these).

Don't worry about whether the clock is working or not. Even if it doesn't function, I can always use the parts.

Speaking of parts, I'm also interested in finding MM5311 and MM5315 clock chips, 7441 and 74141 driver ICs, and Nixie tubes to build and repair other old clocks. (I have more information about Nixie tubes here.)

If you have one of these clocks, or some spare parts, gathering dust or headed for the trashcan, please drop me a line!

For instance, the stopwatch to the left is from 1973, uses Panaplex display elements and requires four 'C' cell batteries to operate.

For more information, click here.

If you have an old digital stopwatch like these that you'd like to part with, please send me an e-mail!

From the 1968 HP Catalog:

2509A Digital Clock is a precision time source used to supply time information to the data system and initiate measurements at predetermined intervals. Time-of-day is available visually and as an electrical output. It supplies time on demand, permitting associated system to operate independently of clock. All solid-state, it features pushbutton selection of timing outputs at intervals from 1 second to 1 hour. Time reference derived internally or from external 1 pps signal. Provision for 100 kHz external reference optional. Easy manual or remote time set. BCD output. Panel height 5 1/4" (133 mm). Price: 2509A, $2,250.

The particular model I'm looking for has an all-black case with a round red lens. A thin silver ring surrounds the lens. The lens itself has "Texas Instruments" embossed in the red plastic. This model is referred to as "Series 500."

I'm looking for a replacement movement mechanism to return this tabletop clock to functioning condition.

The label on the back indicates the following:

• Model Number: 622-300
• Movement Number: 354145E
• Case Number: 5251
• Dial Number: 0334

The response I received from Howard Miller was that this model was last manufactured in 1986 and has been discontinued now for more than a decade. Unfortunately, no parts are available from them.

If anyone has one of these movements, perhaps in a clock they no longer wish to keep, please send me an e-mail.

I'm looking for the actual 5214 device, or at least more information about it (like a picture or dates of manufacture?).

The cover also has a few scratches on it, so either a replacement or a good way to clean and smooth the existing one would be welcome.

As you might expect, I'm looking for a manual.

The tens-of-seconds digit doesn't light up, but the clock itself appears to keep time. Also, one of the three push buttons on the bottom appears to be missing or broken. So, I expect I'll be needing spare parts as well.

There is a mention of this clock on page 50 of Michael Robbins' book Electronic Clocks and Watches. The caption reads 'A TTL clock with seven segment incandescent display.'

An ESE (E.S. Enterprises) sales brochure from 1973 doesn't show the ES-10, so it's either an earlier product that was discontinued, or it was introduced after 1973. The closest device in the brochure is an ES 112 Digital Clock, which shows hours, minutes and seconds and has three controls (fast advance, slow advance, and hold) for setting the time. ESE also offered a kit version of this clock as well as a twenty-four hour model (the ES 124).

The brochure lists ESE headquarters as 506 Main Street in El Segundo.