[time-nuts] HP Z3817A Reverse Engineering (continued)

[Christopher Hoover]

Hello fellow nuts.

Long time.

This is 14 years in the making as my notes when I put this away are dated
2009, but I finally figured a few things out and got the Z3817A to
discipline the E1938:

-------------------------------- Receiver Status
-------------------------------

SYNCHRONIZATION ............................ [ Outputs Valid/Reduced
Accuracy ]
SmartClock Mode ___________________________   Reference Outputs
_______________
>> Locked to TIMEREF2: stabilizing freq       TFOM     3             FFOM
  1
   Recovery                                   1PPS TI +0 ps rel to TIMEREF2
   Holdover                                   HOLD THR 1.000 us
   Power-up                                   Holdover Uncertainty
____________
                                              Predict  432.0 us/initial 24
hrs

ACQUISITION ........................................... [ TIMEREF2 1PPS
Valid ]
Tracking: 0 ____   Not Tracking: 0 ________   Time
____________________________
                                              TIME     --:--:-- [?] -- ---
----
                                              GPS 1PPS Invalid: not tracking
                                              ANT DLY  --
                                              Position
________________________
                                              MODE     Hold

                                              LAT      --
                                              LON      --
ELEV MASK --                                  HGT      --
HEALTH MONITOR ......................................................... [
OK ]
Self Test: OK  | Int Pwr: OK   Oven Pwr: OK   OCXO: OK   EFC: OK   GPS Rcv:
OK


I documented my findings here:

  https://github.com/charlieh0tel/ee_stuff/tree/main/projects/z3817a

and here (partial schematic of the power/interface board):

  https://github.com/charlieh0tel/ee_stuff/tree/main/projects/z3817a

Thanks to Peter Grounds for help back in 2009.

I suspect it wants Motorola/i.Lotus on the RXD, but I didn't have a chance
to try that.  NMEA sentences from a Furuno from a 58503A didn't do anything.

I still would like to dump the MPU Flash.

-ch
ES 73 DE AI6KG