The displays are self contained modules hera must have used in a number of their products. A local 7805 regulator - they run on 16V AC - a 741 op amp, a CA3161 BCD to 7 segment decoding driver and at the heart of it a CA3162 analog to digital converter for 3-digit multiplexed and BCD encoded output.
TIP140.PDF
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Datasheets
Bun's Lab
The displays are self contained modules hera must have used in a number of their products. A local 7805 regulator - they run on 16V AC - a 741 op amp, a CA3161 BCD to 7 segment decoding driver and at the heart of it a CA3162 analog to digital converter for…
They measure a voltage and that can be adjusted with this single and multi turn pot.
Everything tracks and displays correctly now. The old filter caps are still fine enough. I will still replace them though, once I get around to ordering them.
I picked it up many eons ago for 20 bucks on ebay. Now somehow it goes for 90-100?? With some people even asking outrageous 200 for it. The specs certainly haven't gotten any better. What is it with this inflation of retro gear prices lately?
The operation manual dates to October '79. It's already driven by a microcontroller, a MOSTEK MK3870 with 64 bytes of scratch RAM, 64 bytes of executable RAM and up to 4k of mask ROM.