Trak Systems 8820 GPS Station Made some progress, LCD was repaired by several cleanings with a lint free cloth and alcohol of the PCB to display contact and careful realignment on assembly. Also removed flat washers which were causing a short between board and case.
The Laser jet III display was very similar but the connector was wrong so it is not the same. My next issue is the RS232 ports which do not appear to work. The closest socket to the RS232 remote I/O connector is empty, it is a 16pin DIP labeled U42. Also in the area is three sockets for the GPIB option which are also missing. My best guess is that U42 is used to customize the interface Hardware handshake and DTE or DCE so maybe I need a jumper block ? I can enter the correct date as MM/DD/YY but it is displayed as 1908 not 2008. As soon as the unit has tracking and locked the date is updated back to March 1989 and the number of days in the display is wrong again. If I don't find an updated firmware to fix the date then may have to hack the main processor eprom to fix the date. A simple fix would be to inhibit the date update and allow hour, minute, second GPS update. Would have to insure the date would roll at 24:00. If so the patch could correct the number of days except for leap years and I can keep the Magnovox GPS. The GPS DO section is working fine as the PPS signal is unaffected by date issues. Would like to have some info on the Magnovox engine like pin out so if it does need replacement I can make the mods to the interface board. Stanley _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
