can anyone help? GC-MS HP..5972

[mickygd]

Can anyone help?

My 5972 is not working. We rarely use this one so we had it off (vented and shut down) for about 1 month.

a couple of days ago I turned it on and pumped down because I knew I was going to use it.

Now it gives me nothing. I tried to do an auto tune but I got no peaks and the em volts kept going up (above 2000) so I aborted the tune. We usually get 1253 em volts.

My question, what are the first steps?
I got and paid for refurbishment on this machine and it arrived this summer. It has always worked wonderfully although we rarely used it.

any help is appreciated.

Thanks.

[Consumer Products Guy]

(1) I need to ask: what is the MS temperature (this is different than the transfer line temperature)? Go to View, Manual Tune. Then go Status, Vacuum/Temp Status. Record MS Temperature and post back. The transfer line interface must make real good connection with the detector to transfer its heat properly. Also, Foreline Pressure should read "Pressure OK".

(2) Were you doing the full autotune or the Quick Tune? Anyway, if you were using full autotune, I would select the "reset to Defaults" condition and try that.

[AICMM]

Mickygd,

What does Vacuum status say the foreline pressure is? Do you have a high vacuum guage mounted and if so what is the pressure? When you try to manually tune, do you hear the PFTBA valve click on? If you go into manual tune and look at a spectrum scan do you see anything at all? With the PFTBA off, how much water and nitrogen/oxygen do you see?

Have you thought about contacting someone like MLS Technologies? They are nearby and might be an inexpensive alternative for you to look at.

Best regards.

[mickygd]

Thanks for replying to my post.

to answer your questions...

I did the quick auto tune.
the MS source is 121 deg C
foreline pressure is 57 mtorr

I will try a manual tune....i didn't hear the 'click' when I did the auto tune like I usually do. Anyway I did a standard run with 5 ppm PAH and got no peaks.

P.S. I've scheduled MLS to come out in Jan for routine checkup so I'll get the full lowdown then....maybe I'll be helping others by then on this forum.

thanks.

any thoughts on a next step?

[AICMM]

mickygd,

Normally you get a filament emission error message, but have you flipped over to the other filament.?

Fore pressure is fine, temp is fine, now the question is what do things look like from manual tune.

Best regards.

[Consumer Products Guy]

mick - I think you found your main issue: your MS temperature is extremely low, it should be at least 175 degrees C. Check your transfer line temperature, it should be maybe 280 C, that is where the MS gets its heat. If the transfer line temperature doesn't meet its set point, that's your problem. If it DOES reach its set temperature, sounds like you'll need to vent, remove MSD, and tighten the transfer line fitting to try to get better contact so the MS will heat, then re-assemble and pump down. This is a relatively common issue, the newer models have their own heat source.... And usually when the filament is burnt out the error message is "No emission current", so I don't think that's your issue.

[mickygd]

I did a good cleaning on the ion source and it's resolved.

I think what happened was that having the machine off for so long in addition to haveing helium continuously on gummed up the source.

I guess two months of impurities in the helium added up to a lot.

Thanks to everyone, I've learned a lot.