Problems getting board to lock into 10MHz GPS.
History:
1. L20 was lifted so replaced with ~ 5uH SMD inductor
2. 12V power was loading down 5V supply and squealing - removed DC/DC daughter board and using separate 5V and 12V supplies.
What appears good:
1. Boots up and can communicate through 4-pin RS232 connector.
2. Completes site survey
3. Has 10MHz at output of OSC close to 10MHz.
4. Has output at 1PPS MCX connector.
Problem symptoms:
1. Will not feed through 10MHz clock after successful site survey. Can force 10MHz output at MCX connector by toggling MACI button on PCB.
2. LED:GPSLock = 0 which probably means the system is not attempting to output the 10MHz clock.
3. OUTPut:STATe = UNLOCK and SYNChronization:FFOMerit = PLL unlocked ; Indicates problem with PPL for the 10MHz OSC
4. status shows #H/W FAIL ---------- [ LINK ] and #OPERATION ALARM --- [ EFC ], Not sure what LINK is. EFC possible "Electronic Frequency Correction"
?
5. ALARm:HARDware? = NONE; After all this I would think there would be a hardware alarm !!??
6. Tried changing "satellite elevation mask" (GPS:SAT:TRAC:EMAN) to different values but made no effect.
So it appears the PLL is failing is related to EFC. Is there some hidden setup I'm missing? Any signals to check?
UCCM-P > SYST:STAT?
-------------------------------------------------------------------------------
090-03861-03 serial number W********* firmware ver 1.0.0.2-01 LINK mode
-------------------------------------------------------------------------------
Reference Status __________________________ Reference Outputs _______________
XX Ref 8KHz 0: [LOS]
TFOM 9 FFOM 3
UCCM-P Status[OCXO WARM]
>> GPS: [phase: -1.96e-06, adjusting freq]
ACQUISITION ................................................ [ GPS 1PPS Valid ]
Tracking: 5 ____ Not Tracking: 6 ________ Time ____________________________
PRN El Az C/N PRN El Az GPS 12:15:21 06 JUN 2016
1 23 253 33 10 7 147 GPS Synchronized to UTC
3 38 313 34 22 62 292 ANT DLY +0.000E+00
14 36 75 38 23 11 293 Position ________________________
16 23 176 31 25 11 38 MODE Hold
32 29 85 43 26 47 151
31 60 27 LAT N **:**:**.***
LON W **:**:**.***
HGT +***.** m (MSL)
ELEV MASK 10 deg
-------------------------------------------------------------------------------
UCCM-P > status
- UCCM Slot STATE -
1-1. #Now ACTIVE STATUS ---------------- [OCXO Warm]
1-2. #Before ACTIVE STATUS ------------- [Wait for GPS]
2-1. #Reference Clock Operation -------- [Not Used]
2-2. #Current Reference Type ----------- [GPS]
2-3. #Current Select Reference --------- [GPS 1PPS]
2-4. #Current Reference Status --------- [Ref Analyzing]
#GPS STATUS ----------------------- [Available]
#Priority Level ------------------- [GPS > LINK]
#ALARM STATUS
#H/W FAIL ---------- [ LINK ]
#OPERATION ALARM --- [ EFC ]
3-1. PLL STATUS ------------------------ [Enable]
3-2. Current: PLL MODE ----------------- [OFFSET OBSERVATION MODE]
Command Complete
UCCM-P > OUTPut:STATe?
UNLOCK
Command Complete
UCCM-P > LED:GPSLock?
0
Command Complete
UCCM-P > ALARm:HARDware?
NONE
Command Complete
UCCM-P > SYNChronization:FFOMerit?
PLL unlocked
Command Complete
UCCM-P > SYNChronization:TFOMerit?
Greater than 1E8 ns
Command Complete