Posted Tue, 19 Mar 2024 15:37:20 GMT by Kalinchuk, Paul
I bought a DPO7254 oscilloscope that seems to work fine except that it keeps falling an SPC. All the channels seem to work. The only thing I see is that channel 2 and channel 4 are not exactly on 0 but maybe 1.5mV lower then 0. 
How can I get the error codes to see why the SPC is failing?
Posted Tue, 19 Mar 2024 16:55:02 GMT by Teles, Afonso
Details on how to use the built-in instrument diagnostics are on page 4-26 of the service manual: https://www.tek.com/en/oscilloscope/dpo70000-mso70000-manual-6
Posted Tue, 19 Mar 2024 17:48:13 GMT by Kalinchuk, Paul
I seen that already but I guess I’m missing something. The diagnostics tests do not have any faults. Thanks for the response.
Posted Tue, 19 Mar 2024 17:55:09 GMT by Teles, Afonso

That's interesting, might hint that your acquisition hardware is good but some of the SPC hardware is bad.

Posted Tue, 19 Mar 2024 19:54:24 GMT by Kalinchuk, Paul
I took it apart and checked resistance on all relays. I powered them up one by one and they all are within 0.1Ohm between contacts. I’d like to see what the reason for the failed SPC so I can at least have an idea what channel is causing it. 
Posted Tue, 19 Mar 2024 22:15:43 GMT by Kalinchuk, Paul

I was able to locate the error logs, seems like SPC is failing due to a missing trigger on channel one? Channel one trigger seems to work fine though. Here is the error log:

SHOWTIME: SPC: starting 17:59:54
SHOWTIME: SPC starting step : Set SPC defaults
SHOWTIME: SPC completed step : Set SPC defaults 00:00:01
SHOWTIME: SPC starting step : Get Temperature
SHOWTIME: SPC completed step : Get Temperature 00:00:00
SHOWTIME: SPC starting step : Hfd144 safe 50ohm values
SHOWTIME: SPC completed step : Hfd144 safe 50ohm values 00:00:01
SHOWTIME: SPC starting step : A2D linearity cal
Linearity cal took 5 passes
SHOWTIME: SPC completed step : A2D linearity cal 00:00:18
SHOWTIME: SPC starting step : Hfd144 Null input current
SHOWTIME: SPC completed step : Hfd144 Null input current 00:00:06
SHOWTIME: SPC starting step : Gain Normalize hfd144
SHOWTIME: SPC completed step : Gain Normalize hfd144 00:00:02
SHOWTIME: SPC starting step : A2D gain/offset pass 1
A2D gain 194 - 450; A2D offset 80 - 794
SHOWTIME: SPC completed step : A2D gain/offset pass 1 00:00:32
SHOWTIME: SPC starting step : Et Cal
SHOWTIME: SPC completed step : Et Cal 00:00:13
SHOWTIME: SPC starting step : Demux Phase Cal
digPhaseCal succeeded
SHOWTIME: SPC completed step : Demux Phase Cal 00:00:03
SHOWTIME: SPC starting step : A2D interleave
SHOWTIME: SPC completed step : A2D interleave 00:00:21
SHOWTIME: SPC starting step : A2D gain/offset pass 2
A2D gain 192 - 449; A2D offset 80 - 793
SHOWTIME: SPC completed step : A2D gain/offset pass 2 00:00:14
SHOWTIME: SPC starting step : A2D gain/offset pass 3
SHOWTIME: SPC completed step : A2D gain/offset pass 3 00:00:00
SHOWTIME: SPC starting step : A2D gain/offset cleanup
SHOWTIME: SPC completed step : A2D gain/offset cleanup 00:00:00
SHOWTIME: SPC starting step : Hfd144 varigain DAC
SHOWTIME: SPC completed step : Hfd144 varigain DAC 00:00:03
SHOWTIME: SPC starting step : LF Comp for M668
SHOWTIME: SPC completed step : LF Comp for M668 00:00:03
SHOWTIME: SPC starting step : Hfd144 offset DACs
SHOWTIME: SPC completed step : Hfd144 offset DACs 00:00:06
SHOWTIME: SPC starting step : M668 offset DACs
SHOWTIME: SPC completed step : M668 offset DACs 00:00:04
SHOWTIME: SPC starting step : Hfd144 stepgain
SHOWTIME: SPC completed step : Hfd144 stepgain 00:00:11
SHOWTIME: SPC starting step : M668 stepgain
SHOWTIME: SPC completed step : M668 stepgain 00:00:12
SHOWTIME: SPC starting step : Hfd144 Bandwidth limit gain
SHOWTIME: SPC completed step : Hfd144 Bandwidth limit gain 00:00:02
SHOWTIME: SPC starting step : Hfd144 offset
SHOWTIME: SPC completed step : Hfd144 offset 00:00:09
SHOWTIME: SPC starting step : M668 offset
SHOWTIME: SPC completed step : M668 offset 00:00:05
SHOWTIME: SPC starting step : Hfd144 offset gain-correction
SHOWTIME: SPC completed step : Hfd144 offset gain-correction 00:00:40
SHOWTIME: SPC starting step : M668 offset gain-correction
SHOWTIME: SPC completed step : M668 offset gain-correction 00:00:41
SHOWTIME: SPC starting step : Gain Validation
SHOWTIME: SPC completed step : Gain Validation 00:00:00
SHOWTIME: SPC starting step : Trig gain/offset/hysteresis
** 1B failed -- no trigger found. **
18:04:11:125[2456] caltrig.cpp:calTrigGainOffsetAndHysteresis(123) error calibrating gain/hysteresis on channel 1
CAL: SPC returned an error in step Trig gain/offset/hysteresis
SHOWTIME: SPC: failed and quit 00:00:10
total time 00:04:17
CAL: SPC failed
DRAM is Mt_ddr2_512M_667

Dram Calibration results:
-------------------------
DramCal has PASSED on all Demuxs

DRAM is Mt_ddr2_512M_667

Dram Calibration results:
-------------------------
DramCal has PASSED on all Demuxs

digPhaseCal succeeded

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