[time-nuts] HP 58503A GPS time and frequency receiver - How do I determine why the ALARM LED is on?
Dr. David Kirkby (Kirkby Microwave Ltd)
drkirkby at kirkbymicrowave.co.uk
Wed Jan 25 10:08:58 EST 2017
I've got an HP 58503A purchased from China a couple of years ago. It has a
bit of a hard life, having been in water at some time. But it seems to work
ok, as far as I can tell. Today there was a power failure for 5 minutes or
so. The red ALARM LED is on. It is not clear to me why, although of course
I'm aware there was a power outage, which almost certainly caused this,
although I can't be 100% sure.
Could it be that the log is full? I had a program running trying to get the
position multiple times in a loop, to get some sort of average, so I can
well believe I filled the log up. But this was a few weeks ago. The log is
clearly full .
scpi > diag:log:read:all?
Log status: Full
Log 001:19970504.00:00:00: Log cleared
Log 002:19970504.00:00:00: System preset
Log 003:19970504.00:00:00: Power on
Log 219:20170107.05:30:17: Position hold mode started
Log 220:20170107.05:30:57: Holdover started, not tracking GPS
Log 221:20170107.05:31:03: Survey mode started
Log 222:20170107.05:33:04: GPS lock started
Nothing has been logged since 7th January. I know for a fact there was a
power outage on the 19th and today (25th), so I suspect the log being full
has NOT caused the ALARM light to come on. A fault, that is not logged, has
scpi > SYSTEM:STATUS?
------------------------------- Receiver Status
SYNCHRONIZATION ............................................. [ Outputs
SmartClock Mode ___________________________ Reference Outputs
>> Locked to GPS TFOM 3
Recovery 1PPS TI +9.5 ns relative to
Holdover HOLD THR 1.000 us
Power-up Holdover Uncertainty
Predict 432.0 us/initial 24
ACQUISITION ................................................ [ GPS 1PPS
Tracking: 6 ____ Not Tracking: 1 ________ Time
PRN El Az SS PRN El Az UTC 15:03:50 25 Jan
5 23 186 73 24 21 252 GPS 1PPS Synchronized to UTC
13 84 110 81 ANT DLY 0 ns
15 59 289 94 Position
20 45 245 96 MODE Hold
28 51 76 104
30 27 68 83 LAT N 51:39:04.155
LON E 0:46:36.381
ELEV MASK 20 deg HGT +45.55 m
HEALTH MONITOR ...................................................... [
Self Test: Err Int Pwr: OK Oven Pwr: OK OCXO: OK EFC: OK GPS Rcv:
The self-test shows an error, but no indication what the error was, as the
log was full.
I have a fairly good idea what may have happened. Sometimes when the unit
is powered on, the voltages on the PSU appear to go out of spec. I'm not
convinced this is really happening, as a multimeter on peak hold could not
catch any glitch, but I have not tried a fast scope.
I'm just wondering if there's anything else I can do to see what caused the
LED to come on. I suspect if I execute the self-test, it will pass and the
light go out, but I'd rather find the reason before doing that.
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