Chromatography Forum

hi everybody

huge cash prizes for anyone who can solve this one for me!

i have a Thermo LXQ ion trap mass spec which seems to be very temperamental.

we bought the instrument in 2007 - but the main RF board needed to be replaced twice already.

I started having problems with communications on it about a month ago. as soon as the pc goes to standby the instrument looses comm's.
When I reset it, the RF board does not seem to go on ( I checked the vacuum)

the engineers established that there is a fault on the RF board and replaced it.

this only seemed to make the problem worse, with comm's going in the middle of tuning and calibration procedures.

after carefull and time consuming tuning of the RF board and upgrading of the software...... we saw light at the end of the tunnel.... but low and behold.... it did it again on the first calibration I attempted.

to make a long sad story short; if any of you have worked on a THERMO instrument before and experienced this, i'll apreciate any ideas!?!

thanks

Not a "Thermo" solution, but I'd go into the PC's CMOS and Control Panel power options and make sure that it never goes into sleep/standby/hibernate mode. Screen savers should be OK.

Beyond that, make sure Thermo is committed to seeing this issue through and buy the service contract if you have any doubt of this.

Good suggestion.
We had the same problem with other vendors' instrument: the network card went to stand-by loosing the communication. When we changed this behaviour we solved our problem but in all the cases, the service engineer suggested the solution.

I've had problems with communication boards on the PC end that would stop communicating after the PC goes into standby.

What troubleshooting have you done on the PC end?

thanks for the reply DR. PC settings is as it should be, as that was part of the initial problem.
however we can't seem to figure out why it looses comm's with a new board?

will let you know as soon as we find a solution, THERMO is working overtime on this one.

MassSpecM,

We had a similar problem (Sorry, different mfg) in that every time the system resources of the PC fluxuated, communication was interrupted. This was solved by changing the PC CMOS settings as recommended above, and upgrading the system RAM memory.

What are the specs of the computer controlling the instrument? Too little processor speed or RAM memory will cause the computer to "lock up" when running multiple programs, especially memory-intensive ones. Even if this lasts for only a few seconds, it can be enough to disrupt the sensitive MS electronics.

Regards,

A.W.

can't say we've ever had anything that drastic, and I can't really understand the link between losing communications and total failure of internal electronics of the MS.

However, if we turn the PC off while leaving our DecaXPplus (i.e Thermo ion trap but not same as yours) turned on, with the spray chamber open, it loses communications and needs to be reset (which it always manages without trouble). If we do this with the spray chamber closed, it does not. This is completely consistent and always true.

I've always believed this is because the instrument sends continual messages that the spray chamber is open, and gets upset if there is no PC to listen. If the instrument is idle and spray chamber closed, I'm not sure what communication, if any, goes on.

MassSpecM,


What are the specs of the computer controlling the instrument? Too little processor speed or RAM memory will cause the computer to "lock up" when running multiple programs, especially memory-intensive ones. Even if this lasts for only a few seconds, it can be enough to disrupt the sensitive MS electronics.

caged alphinist thanks! will definitely look into it! Do you think that the performance problems on the pc can physically damage MS electronics? (RF board needed to be replaced twice already)

lmh - ours does that as well. or if we replace the source to APCI from ESI or vice versa. - but as you say that is a consistant thing. part of the routine.

thanks

If there's a little hub or switch between the instrument and PC (if it's ethernet), try different ports on it or replacing it if you have another. If the cables were made "in house", try replacing them... these things do go bad, get kinked etc. etc...

hi guys!

almost forgot to send you a reply on this one.

Problem finally sorted;
LXQ and LTQ Rf boards look exactly the same - only difference ONE digit on the serial no.!

so you can imagine why we would have the problems we are having if you have the wrong board in the instrument.

also, installed more RAM! the virtual memory was set too low, as soon as we fixed this, no more "freezing"

the engineer was brilliant! he sat for 2 days replacing hubs, tuning RF boards, taking out power supplies to get to the root of the problem.
and all he asked for in return - a cup of STRONG coffee every hour!

thx for the replies!
now we can work again!yey!