Products > Test Equipment
Gould Ultima / Nicolet Accura DSO software needed.
shakalnokturn:
Thanks for the uploads...
Now because of that, once I get CH4 sorted, I feel I ought to install a windows XP on a much faster mainboard / CPU. No doubt that will get me into a whole lot of extra trouble.
What was wrong with your PSU?
--- Quote from: Parus on June 24, 2021, 11:34:00 am ---btw. 4-ch interleaved, full BW, 8 bit is one of the auto calibration tests
--- End quote ---
Yes I noticed that as I've been through a few auto-calibrations myself.
Funnily it does not throw an error when calibrating that mode, maybe I'm foolish in assuming it should if something is wrong. :-BROKE
Searching around the system files I noticed there were several versions of the Jungo drivers:
GNT_PCI_4700_9050_V503.inf
GNT_PCI_2730_V505.inf
GNT_PCI_4700_V522.inf
GNT_PCI_4701_V522.inf
GNT_SYNCHRO3_V522.inf
I was expecting my scope to use the GNT_PCI_4700_9050_V503 driver as the slow acquisition board is PLX9050 based but it doesn't. Maybe I ought to experiment forcing other drivers to see how it behaves on 4 channel interleave.
Does your cal error actually show anything obviously wrong when looking at a waveform in ETS such as a very jagged / jumpy waveform with sample points out of sequence?
I'm not sure where the calibration is stored and if all in a single place, I've attached whatever seemed calibration related on my scope (CalibrationData.dat / CalTestResults.txt / VGen.log) maybe replacing CalibrationData.dat and running an auto cal over that will be enough to satisfy yours...
Parus:
If it ain't broken, don't fix it. Specialy a mainboard upgrade is a bit useless and might fail. It's very timing sensitive, changing the more advanced settings in the bios other than default often makes the system hang. My NT4 system had errors that I could not repair with the standard install cd because it was a high security version (that made me smile), no USB support, obsolete network and a terrible user interface. I have upgraded CPU, memory (windows really likes that), networkcard and a extra USB card to create a bit of extra head room for a "newer" OS. With XP running it's just a bit more user friendly but not a better scope. If you are happy with your W2K install, just leave it.
Because this is a little bit difficult to accept for us explorers you can also add a second scratch HD and start experimenting.
For the search enigine archives:
The PSU in the Ultima is a third party Ferrus FP250-710. Itś a low frequency (36kHz) push-pull smps with 3 separate switching circuits on a common PWM, 7 output rails at 700W max total.
A real pain in the nose to work on, no schematics, no info, compact, components hard to reach, testleads don't fit or hitting other components and because of the layout of the 3 circuits on the baseboard no clear separation between prim. and sec. So most of it is hot and can bite humans and equipment pretty bad what made live testing a bit tricky.
My PSU was very dead, no output, not looping in startup and no visible damage. First thing: check primary, all ok DC present. Next: gate signal at the regulated startup rail, present but low and not a happy PWM, at least not enough to pull the FET open. That signal comes from a driver transformer which is just a small ring core with 3 solid wire windings, not a real failure suspect. So I started chasing a short of some kind that pulled the PWM down in the other circuits.
Driver circuit second switcher, OK. Third switcher OK, feedback OK. PWM circuit: SG3525 fully functional but output weak. This is a common old age thing where the open collector output drivers are getting leaky, higher voltage drop, lower output voltage and some extra heat that accelerates this proces. Chip will fail in the near future, specialy if it drives the transformer directly.. Simple fix, just replace. Now with the PWM on level again i'ḿ back to starting point, but this time on the primary side of the driver transformer. Desoldering it's leads, check: open .... shoot.
Easy fix: made with a piece of wire a new primary winding on top of the other, and with this it came back to live.
Next big question is how is this possible? The 100mA running can't even scratch that wire so it must be a combination of thermal and the ultra-sonic coil beating.
PSU fact: it has a small 12V standby DC/DC supply that is powered from the main bulk capacitor. Without powerswitch the complete primary is always on including the divider/bleeder resistors. That explains the 15W standby power usage.
For the calibration i will try a "smart" approach with compairing the files of the old with the new (and yours).
A bit long weekend story, salut
Parus:
After reading the service manual of a Gould 400 DSO i tried the same approach on the Ultima 500 and found the "hidden" section of setup and calibration.
In the GUI go to utils menu with a.o. auto calibration, push the last button of the vertikal screen colunm 4 times and an extra option "engineering" will appear. In this section all the low-level magic can be monitored and calibrated.
I have cleared my sticky Skew/ETS warning, but meanwhile CH2 got very noisy and the trace is jumping around, grrrr
shakalnokturn:
RaymondMack: Thanks for the photos and too bad for the HDD ..
It looks as if the hardware doesn't share much in common with the Ultima 500 after all, the acquisition and front-end PCB's are very different. The common parts seem to be the PCI slow acquisition, front panel, LCD, CCFL inverter. (Maybe PSU?)
Parus: Nice find that secret service menu, I wouldn't have thought of it...
Maybe worth reflowing the resistor network on CH2 as mentioned in a previous post.
If you have removed the coax interconnect make sure the connecors have been mated correctly. If you don't align them perfectly the inner pin can easily plug just next to the two curved spring contacts, giving a poor contact and the symptoms you have.
If this has happened the spring contacts will need realigning slightly. Don't ask me how I know...
shakalnokturn:
Went back inside and see if the CH4 intermittent noise could be solved. Took a few more shots.
In the end the most likely was that there were also weak solders on the other half of the shielding (the one that wasn't almost floating around) and that was causing the problem.
Took a few pictures and found a couple more details in there that didn't impress me: Lowish clearance between the aluminium plate that holds the BNC's and tracks on each input, what looks like solder paste residue, some found on the tops of a couple of SOT-23 packages, worse on the front sides of two of the FE ASICs, over several leads.
Also a tendency the shielding has to rip one of the tracks to a nearby capacitor... (Pictured on CH2.)
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