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/1a1055f4-03af-4374-b0f9-9457763de2e2n%40googlegroups.com.
