Agilent MSD Quad DC fault

[hfredricks]

Hi all,

I'm troubleshooting a "Quad DC fault" on our G1956B MSD. I'm emailing with an engineer but I thought I'd put it out to the LCMS community as well, does anyone have any experience of this kind of error? seems like it could be anything as simple as 'light' dirt to a blown board... I'm happy to get inside if I need to, but right now I'm at a loss as to where to start.

thanks, Helen

[JTM]

First thing to do is to check all of your connections.

A) Check that they are actually connected and the connections aren't frayed/etc. Clean off any oxidation on the pins/connectors.

B) Check the fuses in the back as well.

http://www.chem.agilent.com/Library/Sup ... a03801.pdf

Those are the HP part numbers for the fuses, etc, you might need to get new P/Ns from cust service.

Other helpful links:

http://www.chem.agilent.com/en-US/Suppo ... fault.aspx

That's what you hope for, anyway. If it's the board, then it's a pain.

[mxa]

Hi all,

I'm troubleshooting a "Quad DC fault" on our G1956B MSD. I'm emailing with an engineer but I thought I'd put it out to the LCMS community as well, does anyone have any experience of this kind of error? seems like it could be anything as simple as 'light' dirt to a blown board... I'm happy to get inside if I need to, but right now I'm at a loss as to where to start.

thanks, Helen

Hi Helen - it's marc, I've been emailing you about your 1956B.

For everyone else, I have the same agilent 1956B instrument as Helen, and coincidentally just got the same error the other day, notably the "Quad DC fault" error. After some poking around, and after acquiring the hardware troubleshooting guide (which I can provide to anyone who wants it), it's fairly certain that our "analyzer board"s are bad and need replacement. Agilent charges about $3300 for them. I'm wondering if anyone knows of any companies that either repair or refurbish mass spec printed circuit boards? I heard that GenTech Scientific does some logic board repairs, but apparently not for Agilent instruments, maybe Thermo Fisher ones.

I can probably perform the replacement of the board, but I'm just hoping to get out of paying $3300 for the part!

I found this somewhat generic web page, suggesting that this company fixes the analyzer board (agilent part # G1946-65250), but they don't seem to respond to emails.
w ww.acsindustrial.com/repair-catalog/item-14681.html

Any other thoughts? thanks!
-marc

[AICMM]

mxa, hfredricks,

For what it is worth, contact Cal-tech scientific in California. They may be able to help you with this problem. (Met them at a previous Pittcon.)

Best regards,

AICMM

[hfredricks]

thanks for your suggestions guys, I'm working on it - I'll share the joys / woes when I make a breakthrough!

Helen

[mxa]

mxa, hfredricks,

For what it is worth, contact Cal-tech scientific in California. They may be able to help you with this problem. (Met them at a previous Pittcon.)

Best regards,

AICMM

Hey AICMM --
thanks for the tip. I got in contact with them, and they might help repair the item for less than Agilent would charge for the replacement.

I've figured out more stuff related to this problem, and ultimately I'll post a nice resolution/brain-dump, after I figure out a couple things.

For now, I've learned that the U+/U- cable connects from the analyzer board to the RF coil box. It's a three wire connector, and the middle wire is ground. According to the Agilent 1946 trouble shooting guide, you can test if the analyzer board is working by doing a "manual tune" in ChemStation and trying a couple different masses, while checking U+/U- with a volt-meter. (I believe measuring DC voltage). The connector carries high voltage, and I did shock myself yesterday, so be careful with it It is easy to safely test the voltage with a multimeter though.

According to the troubleshooting guide, depending on the mass you "tune" to, you will see these U+ and U- values:

mass U+ U-
-------- ------ -------
118 +30 -30
622 151 -151
922 223 -223
1522 369 -369

On my instrument, my U+ and U- are +796 and -266 (or +796 and -184), no matter what mass I set the manual tuner to. So they are wrong in magnitude (but correct in polarity). I'm assuming this is an analyzer board issue. The troubleshooting guide says that a broken analyzer board should be producing +0/-0 though. Hmmmm.... Maybe my board is broken in a different way.

Last question, in case anyone knows:

My analyzer board is an agilent G1946-60250, while the replacement that Agilent wants to provide is a G1946-65250. Anyone know the difference between these boards? I'm wondering if the latter one is improved somehow. I.e. does it make more sense for me to fix my 'old' board (~$1000), or throw down a little extra money and get an improved 'new' board (~$3300).

thanks for any hints.

-marc

[eagle039]

Hi,
since two weeks we now have the same "Quad DC Fault" error as you had.
It comes with an other Message "RF Voltage could not be maintained". As we do not have a troubleshooting guide, may you send me yours?
I messured the Voltage of the +U and -U but it's always 9V and I can not manually Tune the MSD because of an Ion Optics Failure.
I'm wondering if this a additional problem or if it depends on the "Quad DC fault".

Best regards


Sebastian

[Metalboat]

Marc,

Would love a copy of the troubleshooting guide.

Thanks
Richard

[mars]

Marc,
I would love to obtain a copy of Agilent 1946 trouble shooting guide if possible.
LC

[mckrause]

Agilent is providing the 1956 boards because they are out of the 1946 boards. There were no significant changes in the functionality of the boards.

If you can get your 1946 board repaired you should. Certain parts are hard to find for the 1946s, and this is one.

If you have a Quad DC fault, it is almost certainly the analyzer boards. They are not rugged.

For anyone wanting a PDF copy of the troubleshooting guide, please send me your e-mail address and I'll e-mail it to you. Mine is:

mckrause@austinanalytical.com

Mark Krause

[jagoeman]

Hello,

Since last week I have a 'sudden' problem om the good old G1946C MSD : the lower mass peaks are too broad, and I can no longer tune due to peakwidth problems.
The ion optics test fails on 'lens1 flatness' and when a 'frequency adjustment' is done it says : Error, no frequency found ! The quad electronics test passes however.
I checked the quad and ion optics, they are clean, there are no cable problems or bad contacts. The RFPA outputlevel checked via the showRF-mass command is OK.
I suspect an electronic problem in the analyzer board OR the coil box OR the RFPA box OR in the power distribution board but I have no real means to find out where exactly.
I'm very much interested in some troubleshooting guidelines or practical tests in order to find out where or on what board the defect might be situated...
The mentioned troubleshooting guide is probably helpfull if someone might still have it. Also any idea is welcome

Kind regards,

Jan

[jagoeman]

Hello Marc,

I'm having the exact same problem as you mentioned. A Quad DC Fault and U+ and U- DC value are +780V and -250V on the cable behind the coilbox no matter what mass is set.
So the values are not zero or too low as often is the problem with a broken analyzer board but too high, and the wrong value.
So I'm curious if and how your problem was finally solved ? Was it in this case also a defective analyzer board ?

Kind regards,

Jan

I've figured out more stuff related to this problem, and ultimately I'll post a nice resolution/brain-dump, after I figure out a couple things.

For now, I've learned that the U+/U- cable connects from the analyzer board to the RF coil box. It's a three wire connector, and the middle wire is ground. According to the Agilent 1946 trouble shooting guide, you can test if the analyzer board is working by doing a "manual tune" in ChemStation and trying a couple different masses, while checking U+/U- with a volt-meter. (I believe measuring DC voltage). The connector carries high voltage, and I did shock myself yesterday, so be careful with it It is easy to safely test the voltage with a multimeter though.

According to the troubleshooting guide, depending on the mass you "tune" to, you will see these U+ and U- values:

mass U+ U-
-------- ------ -------
118 +30 -30
622 151 -151
922 223 -223
1522 369 -369

On my instrument, my U+ and U- are +796 and -266 (or +796 and -184), no matter what mass I set the manual tuner to. So they are wrong in magnitude (but correct in polarity). I'm assuming this is an analyzer board issue. The troubleshooting guide says that a broken analyzer board should be producing +0/-0 though. Hmmmm.... Maybe my board is broken in a different way.

Last question, in case anyone knows:

My analyzer board is an agilent G1946-60250, while the replacement that Agilent wants to provide is a G1946-65250. Anyone know the difference between these boards? I'm wondering if the latter one is improved somehow. I.e. does it make more sense for me to fix my 'old' board (~$1000), or throw down a little extra money and get an improved 'new' board (~$3300).

thanks for any hints.

-marc

[mckrause]

Hello Jan,

Almost certainly a board error. Pretty common; Agilent should still have stock on remanufactured boards. If not it sounds like Henry Bui can help you (Cal-Tech Scientific)

Mark Krause

[jagoeman]

Hi Mark,

Indeed, I replaced the analyzer board with one from a working MS as a test and now it works again.
I will have a look around for a refurbished / remanufactured board.

Regards,

Jan