RE: AMMRL: Sudden change is 1H Tune windows - No 1H Signal [Solved]

From: Hamish Grant <granth_at_unimelb.edu.au>
Date: Tue, 11 Aug 2015 03:39:24 +0000

Hi again Ken.

We had a very similar experience with our 3-year old Agilent MR400 recently.

I got reports that 1H data was just noise & 13C data was not decoupled. I checked the 1H tuning & got the trace shown below left.

Gradient shimming produced a normal profile & the 13C tuning – at that point – looked normal. I immediately “deduced” that the hi-band RF amp had died (déjà vu!) & contacted Agilent for a quote to replace it. However, a couple of days later, whilst waiting for our system to start the repair process, I re-checked gradient shimming on a whim & this time, got noise. I then checked the 13C tuning (pic below-right) & it was also just noise – not even the hint of a dip as had been observed on the 1H channel.

Immediately got back to Agilent who agreed that the likelihood of both hi & lo-band pulse amps dying within 2-3 days was low & that they would swap the parts order to synthesiser and ref generator boards.

The engineer swapped the synthesiser board first & the system came back to life.

So, we are another data point for your reference. I am thinking – from your comments – that we should seriously consider purchasing another as a reserve if you get enough “negative feedback” about this module’s reliability or lack thereof.

Regards,
Hamish.
-----------------------------------
Hamish Grant
Deputy Manager
Melbourne Magnetic Resonance
Bio21 Institute
The University of Melbourne
Melbourne VIC 3010
Australia
+61-3- 8344 2477
www.bio21.org

[cid:image002.jpg_at_01D0D43B.2288BD10] [cid:image004.jpg_at_01D0D43B.2288BD10]

From: Kenneth Knott [mailto:kknott_at_vt.edu]
Sent: Saturday, 8 August 2015 5:13 AM
To: ammrl_at_ammrl.org
Subject: AMMRL: Sudden change is 1H Tune windows - No 1H Signal [Solved]

Turns out the 1H frequency died on the synthesizer board. Very Frustrating as this is the 3rd time in 4 years we'll be replacing this board. Always one channel or the other - never both.

I'd be curious to hear others experiences with these boards on the MR4 and MR4DD2 systems from Agient/Varian. They seem VERY unreliable.

Thanks

--
Ken Knott
Department of Chemistry
Analytical Services
Virginia Tech

(540)267-6502 (Cell)
(540)231-0885 (Office)
Received on Mon Aug 10 2015 - 17:42:48 MST