Yes the displays are very nice. I was thinking a clock with a few more decimal places might be interesting.
On Thursday, December 31, 2020 at 6:13:41 PM UTC-6 gregebert wrote: > Those are NICE displays. So, you have a total of 20 boards x 4 per board = > 80 LED displays ? Someone went to a lot of effort to wire-wrap those > instead of making a PCB. > > The logic is very simple: MC14511 BDC-to-7 segment decoder, two 74161 > shift registers. As Bill said, you should be able to reverse-engineer this > fairly easily, and then you would need just a few simple signals to control > the shift-registers (clock, data, clear). You could even use some > pushbutton switches to test it out; just be sure to de-bounce the clock > signal. The data and clear signals dont need de-bouncing. > > > > On Thursday, December 31, 2020 at 2:19:22 PM UTC-8 Bill Stanley wrote: > >> Correct, these are a differential receiver to receive the serial (BCD) >> information, 2x8 shift registers to convert to parallel BCD and 4 BCD to >> seven segment LED drivers. >> >> With a bit of sleuthing, the schematic can be reverse engineered, reverse >> engineer the serial format and build or use a COTS CPU like Pi to display >> anything you wish. >> The power supply connector also probably has the serial data (look for >> wires going to the AM26LS32). Somewhere there will be a connection to >> inject that serial stream. >> >> >> -Bill- >> >> >> On Thursday, December 31, 2020 at 1:30:17 PM UTC-8 bani wrote: >> >>> These are not standalone clock displays. They are driven by an external >>> controller over serial. If the controller is not integrated into the >>> PSU, >>> then you are missing the external controller module. >>> >>> Personally I would just design a completely new clock using the LEDs. >>> >>> -Dan >>> >>> On Thu, 31 Dec 2020, Jeffry P wrote: >>> >>> > I purchased a clock display system from a USPS auction about 20 years >>> ago >>> > and recently rediscovered it in my storeroom. There are 20 displays >>> and a >>> > power supply. The displays were housed in a metal enclosure that has a >>> > window cutout for the LEDs. The window had a piece of red colored film >>> and >>> > the LEDs were behind. When I plug the power supply in it will light >>> all 0's >>> > and a decimal point (as seen in photos), but will not start keeping >>> time. >>> > I'm willing to send one of these boards( at my expense) to someone who >>> can >>> > help me get the thing keeping time again. I've attached a few photos >>> with >>> > descriptions of chips that are on the board and voltages measured at >>> the >>> > power supply connector. >>> > >>> > Thank you, Jeffry >>> > >>> > >>> > -- >>> > 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 view this discussion on the web, visit >>> https://groups.google.com/d/msgid/neonixie-l/85636c40-6036-40b9-9426-24310206c979n%40googlegroups.com. >>> >>> >>> > >>> >> -- 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 view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/d0c13683-6f51-429f-827e-3e273ac999b3n%40googlegroups.com.
