I recall that back in the late 1990's, my local post office had a giant USPS logo'ed LED clock on the wall behind the counter that counted down to the millennium. I was very impressed with it and wondered what they would do with it after the count hit zero on January 1, 2000. Well it turns out that after the countdown ended, it became a regular clock. I was hoping it would basically be the end of the program and that they would appear for sale. Never did find out what happened to it as my post office moved about a 1/2 mile away to a larger facility as my community kept growing and the clock was not at the new location.
On Sunday, January 3, 2021 at 4:10:11 AM UTC-5 Alex wrote: > I would suggest that these were never actually used as clocks, due to > their somewhat homebrew look. I suggest they were weighbridge / scale > displays which may of been constructed to give a large readout, driven from > the aux port on a scale unit. Would make sense for a postal service to have > many of those for vans loading up rather than lots of clocks... > > On Saturday, 2 January 2021 at 15:35:06 UTC Jeffry P wrote: > >> I can find lots of clock circuits that are for lower voltage LEDs, but >> these LEDs are 12v. >> >> On Thursday, December 31, 2020 at 4:19:22 PM UTC-6 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/da2c17c5-fb5d-4fdd-94c3-63aec8f4bc93n%40googlegroups.com.
