Dear fellow magnetic managers,
I am writing to update you on the status of my 1995 Varian Inova and to
THANK YOU for the onslaught of e-mails with great suggestions on things
to try for the z0 lock control issue. Your dedication to helping a
fellow AMMRLer is truly amazing!
I tried many of the suggestions, which I'll describe below. Indeed the
issue was with the shim power supply, lower left unit of the console. A
couple of you suggested to reseat these boards, which I did and in the
process blew off some of the 20-year old dust. Many thanks to David
VanderVelde at Caltech, who has the same vintage spectrometer and
provided me with a photo of the lights on the shim CPU board (R-most
board in the shim supply box) and the Agilent part number, should I have
to order a new one in the near future. Via his help I also found the
'reset' button on this board, which made the LEDs go from all on (after
powering up the system) to only 1 LED lit, which is the indication that
this board is working properly.
Also thanks to Tony Montina in Canada who alerted me of the "Super shim
diagnostic", described in the Unity/Inova Technical Manual (chapter 7).
This is a diagnostic tool in which one can use a laptop and connect to
the serial port at the back of the shim CPU, to correctly figure out
what part of the shim supply is not working properly. According to
Tony, the super shim diagnostic runs a test of all of the power rails
for each shim board and the CPU, the CPU is tested, and each shim board
is tested. Fortunately I did not have to take this route, but it is
good to know that it exists and is described in the Varian manual.
Several of you wrote to check the RT shim connections, both at the
magnet and at the J907 port (on my spect) at the back of the console.
Both of these connections were perfectly in place.
A couple of you suggested to check the adapter at the back of the shim
CPU, this is a serial port DB-9 to data jack RJ-45 adapter.
Interestingly the serial connector only has 8 pins (and 9 positions),
and I checked for continuity on all 8 pins. I believe I mentioned in my
original e-mail that I tested the data cable from this adapter to the
MSR board in the main CPU.
A few of you suggested to try using a different account, which I ended
up doing after powering up the spect on Wednesday. I was SO HAPPY to
see that z0 was actually moving AND that the shims loaded and the
numbers were displaying in the start/shims tab in VJ. I believe I'm
safe to say that it was a hardware issue, since everything is behaving
normally in the vnmr1 account as well.
Again, thank you to ALL who responded to my query. I hope I'm not
forgetting to mention any other tests that I did or that you suggested.
With this vintage spectrometer, issues could creep up on a daily basis.
With your help, my spect is back up and running again! :-)
Enjoy your weekend!
Monika
On 8/29/2014 4:15 PM, Monika Ivancic wrote:
> Fellow AMMRLers,
>
> All week I've been bogged down by the following issue and I'm hoping
> and praying that one of you has seen this before and has a good
> solution/suggestion for my issue. I spent almost 3h on the phone with
> an Agilent tech yesterday, and the issue has yet to be resolved.
> First, I have a Varian Inova 500 10.5MHz IF with the host computer
> an hp Z400 with Red Hat, running VnmrJ 3.2A software.
>
> Here are some of the symptoms that I see in VnmrJ 3.2:
> Under the start/lock panel, z0 says that it is at a value of '0'. I
> can move the slider L/R but don't see obvious changes in the lock
> scan. What's more weird, is that the values that get changed with the
> slider, don't update in the "z0 click it" box to the left of that. I
> can change z0 values in the "click it" box, but they don't match the
> value that is changed with the slider. Kind of like no communication
> between the 2 ways possible to change z0. Hmmm...
>
> The other strange thing is that ALL my shim values read 0. Even
> though I load the latest shim file, and I get a message above the
> command line that says "shim file loaded into hardware", when I go to
> the start/shim panel, they're all still at 0. I can load the shims via
> the click box in VJ or use the old fashioned 'rts' followed by an 'su'
> with the same results. Querying each shim in the command line will
> return a number, but this number is not reflected in the VJ start/shim
> panel for the specific shim (ie. z4).
>
> The shim CPU is on and working, with lit LEDs.
>
> I tried testing the data cable between the shim CPU (at the back of
> the console - connects via an adapter to a DB-9 pin connector) and the
> Magnet Sample Regulation (MSR) board on the main CPU.
>
> I switched out the MSR board with one that had been laying around in
> the lab with a note on it from the previous director saying that it is
> still 'squiggly' working (so yes, using a MSR board that we know is
> working may be the way to go).
>
> With the Agilent Tech on the line, we deleted the persistence file and
> reconfigured the 'vnmr1' user (updated the user in VJ). We were able
> to transmit and receive the lock signal BUT can not adjust the
> position/z0.
>
> In the start/lock panel, I have control over lock power, lock gain and
> lock phase, but not z0. The Agilent Tech said he had not seen
> anything like this, so I am hoping one of you has!
>
> Prior to this issue coming up, I had replaced both fans in the main
> Power Supply and one of the fans in the channel 3/4 AMT amps. Prior
> to the fans replacement, we had replaced capacitors in the PTS620 that
> delivers the 1H frequency. I did run a 1H 1D after replacing the
> capacitors in the PTS, and prior to replacing fans, so I was able to
> lock and shim then.
>
> This whole thing is pretty frustrating and we would like to be using
> our spectrometer! :-)
>
> Thank you in advance for your ideas and suggestions.
>
> Cheers,
> Monika
>
--
Monika Ivancic, PhD
NMR Facility Manager (A-212)
Department of Chemistry
82 University Pl.
University of Vermont
Burlington, VT 05405
(802) 656-0285 office
(802) 656-0279 NMR lab
Monika.Ivancic_at_uvm.edu
Received on Fri Sep 05 2014 - 05:05:15 MST