Date: Mon, 17 Jul 2023 16:22:56 +0000
Hi Adil,
I have a few thoughts ...
The first three lines of that error are common and most often indicate that
something is simply wrong with the experiment routing. The fourth line makes
it more interesting. I would be interested to know if the Bruker personnel
had you do any other troubleshooting besides replacing the probe and RF cable.
Also, I assume you're using the default PROTON experiment to make these checks.
If you're not, it's always a good idea to use a known good pulse program for
troubleshooting.
Regarding whether Bruker factory repairs broken parts, as far as I know that's
a local issue - what the local service policies are. There have been some cases
in the US where customer equipment has been repaired instead if simply being
replaced. This usually extends the instrument downtime because in that case,
the amplifier is sent to be repaired and you just have to wait for it to come back.
Since the amplifier replacement also requires the new system be cortabbed, that
most likely adds an extra element of complexity/cost.
Based on the age of the NEO consoles, I would be extremely surprised if any
refurbished parts were available at this point. You can ask Bruker about
the possibility of getting your amplifier repaired instead of swapping it - I'm
not sure how they will respond.
Now, regarding the problem, there are a few things I would try if you haven't
already:
I would try pulsing into a load instead of the probe. And try removing the
preamp from the circuit—pulsing directly into the load (or into the
probe) instead of through the preamp. If either of these eliminated the fault,
there would be useful information there. I would also see what happened if I
set all power levels to 0 - does the error persist in that case?
Sometimes the connections inside the amplifier can work themselves loose.
It might be helpful to take the amplifier out of the console, take the top
off the amplifier, and disconnect/reconnect the little push-on connections.
You shouldn't need to disconnect any of the internal connectors that are screwed
on, but sometimes those little connectors can work themselves loose and cause
problems.
If you have some attenuators and an oscilloscope it might be useful to look
at both the blanking signal sent to the amplifier as well as the output of
the amplifier. You can see if something looks strange with the pulse coming
out of the amplifier and if the pulse extends significantly beyond the end
of the blanking pulse. I would be somewhat surprised if that were the case.
Based on that last line of the error message that I haven't seen before, it
seems possible that the issue is not with the amplifier, but could be with
the preamp instead. So I would be interested to know what happens when you
set the pulse power to 0W or if you pulse directly into a load/probe/whatever
and remove the preamp from the circuit. It seems possible to me that the
T/R switch in the preamp has failed in the receive position and so when you
pulse it's sending the pulses to the receiver instead of the probe - causing
both the mismatch error and the "Transmit RF power detected" error.
Also if you're interested, it might be useful to try detecting, say, 13C if
you've got a standard. If you have a dioxane standard you could always try
first detecting without decoupling, and then try using composite pulse decoupling
(since it uses lower power than the hard proton 90 degree pulse) to see if
the proton pulses are getting to the probe.
Anyway, that's what I can come up with at this point. Good luck.
Cheers,
Mike
[Block U Logo]
Michael Groves (he/him/his)
NMR Operations Manager, D.M. Grant NMR Center
Department of Chemistry
The University of Utah
315 South 1400 East, GH Rm 1487 Salt Lake City, UT 84112
o:801-581-3828
c:385-910-9856
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