The far right column is part of the matrix as you would expect. It's the column adjacent that seems unusual. I guess if the decoding is there for it, you could illuminate a + sign with that column.
On Monday, June 10, 2019 at 12:38:49 PM UTC-5, gregebert wrote: > > I cant figure out why there is a duplicate column of LEDs on the far right > side. > > The IC is probably a custom BCD-to-segment driver specifically for > discrete LEDs. There is only 1 resistor on the board, so the driver IC > probably does the current-limiting. > I'm fairly certain the IC is not MOS/CMOS, so it's probably still OK (not > damaged by ESD), and it should not be too difficult to reverse-engineer the > connector pinout. > > If the LEDs are wired in-series, you can estimate the required > power-supply voltage by measuring the forward voltage of 1 LED (roughly 2V > @ 10mA). > > If they are parallel, I would assume 5V operation. The 120 ohm resistor > would give 23mA thru an LED that has a 2.2V drop and a 5V supply. See how > many LEDs are connected to it. > > Nice find, and I hope you win the auction. > -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send an email to [email protected]. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/ba4f5206-7dad-4b09-81eb-7d30b97dca2c%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
