AMMRL: Repairing low band amp in Agilent MR400

From: Hamish Grant <granth_at_unimelb.edu.au>
Date: Tue, 28 Jul 2015 02:15:55 +0000

Hi Ken.

We have both a 2006 vintage Varian MR400 & a 2013 Agilent MR400. The low band RF pulse amp on the Varian system failed around 2009 & we got a quote from Varian (still in business) for around $40K to replace the entire bottom rack as you have indicated.

Having spent 25 years working with Varian NMR sales & service, I was intimately acquainted with the hardware configuration & had been involved with many service jobs where the “brick” output modules for the RF pulse amps in Unity/Inova systems had been replaced – at costs varying from ~$2K if purchased by the user directly from AMT (later Herley) to ~$12K as supplied by Varian. The policy to extensively “modularise” the MR400 and solder-connect the bricks to the power supply was, I suspect, an attempt to recover some profit after selling a heavily-discounted spectrometer.

Whatever the original concept was, Varian got cold feet after huge customer pushback and subsequently fitted Molex-connector wiring harness bricks which could be easily replaced within the PS module. Although the system we had purchased was an early model with soldered connections, the very enterprising & sympathetic Varian service guy got the P/N for the separate 300W brick – around $8K as I recall at the time – and cut off the Molex plug to resolder it to the interconnects. Thus, I know that the bricks can be ordered separately & will work in older-style MR400 PS modules.

Sadly, I am unable to locate the quote for this item (the 300W lo-band amp) but we recently thought we had a problem with the 60W 1H amp in our Agilent system & got a quote from Agilent for the following:

[Brick-1H-quote-MR400.jpg]

So – I know that these parts are (were??) available from Agilent & sold separately but can only provide the PN for the hi-band module, I regret.

Hope this helps.

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



From: Kenneth Knott [mailto:kknott_at_vt.edu]
Sent: Saturday, 25 July 2015 2:00 AM
To: ammrl_at_ammrl.org
Subject: AMMRL: Repairing low band amp in Agilent MR400

We have an older Varian vintage MR400 which has a failing low band amplifier. Agilent sells the entire power module (both amps, power supply, and shim controls) as one replacement unit.

Does anyone have any experience servicing the individual amplifiers? Are the specifically calibrated or tuned by Agilent?

Thanks,

--
Ken Knott
Department of Chemistry
Analytical Services
Virginia Tech

(540)267-6502 (Cell)
(540)231-0885 (Office)
Received on Mon Jul 27 2015 - 16:16:55 MST