Date: Tue, 28 Jul 2015 15:58:12 -0400
Howdy Ken,
We have two 2007 vintage MR400's, installed January 2008. The 300
Watt low band amps on both have had to be replaced. The first one was in
2012, and at that time Agilent would not sell us just the low band amp;
but, they did give us a discount on the whole "Power Module", which
included a new low band amp and the new user replaceable components.
The second instrument's low band amp was just replaced this year,
2015. Although, we had to go thru two replacement amps to get a good one.
For this second low band amp they sold us just the 300 Watt amp, Part No:
191656301. This was the soldered version, and we did the soldering
ourselves. I would not recommend doing you own soldering unless you are
comfortable using a soldering iron (a good high power iron), and you know
how to work around a high voltage power supply with big capacitors. You
could also have a few scraped knuckles removing and reconnecting the amp.
Both of our original 300 Watt low band amps did not fail completely,
but just started loosing power requiring longer pw90 values. Someone with
some expertise on amplifiers, and schematics would also help, could
possibly find a fix by replacing some individual component(s).
HTH, cheers, Chris
___ ____ __
| | | | \ / |
| | | | Christopher L. Kojiro, PhD ph: (734)-763-2009
| | | | |\/| Co-Director, NMR Services ckojiro_at_umich.edu
\ \__/ | | | Department of Chemistry, The University of Michigan
\____/|_| |_930 N. University Ave. Ann Arbor, MI 48109-1055
On Mon, Jul 27, 2015 at 10:15 PM, Hamish Grant <granth_at_unimelb.edu.au>
wrote:
> 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:
>
>
>
> [image: 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 <http://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)
>
(image/jpeg attachment: image001.jpg)