GC/MS turbo pump not speeding up

Discussions about GC-MS, LC-MS, LC-FTIR, and other "coupled" analytical techniques.

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Agilent 5973 MS coupled to 6890 GC; was up and running and about 2 years ago, when project was over, post-doc using it vented the system and shut everything down.

Went to set it back up today and we're having issues with the turbo pump not ramping up. Rough pump seems to be working properly, no signs of a leak (plugged MS interface) - when powering up the MS it says "System vented" and if we select Pump Down, it starts up and we hear the turbo kick in, goes to about 30% speed then starts dropping down towards 0, all within 2-3 minutes. Checked vent valve, analyzer door seal, pressing while pumping down but somehow this seems to me to be indicative of something different than a large leak (the quick turbo pump speed drop-down), no?

Attempting to pump down through ChemStation, get the message "Pump Down error: MS status fault 400" and "Difficulty with the fan. The high vacuum pump is not ready. The system is in VENT state (high vacuum pump off)". Took the cover off and the fan seems in front of the turbo seems to be running fine and if we blow air over the top rotor of the turbo pump, it seems to spin properly...

Any suggestions would be appreciated.
Trishia wrote:
Agilent 5973 MS coupled to 6890 GC; was up and running and about 2 years ago, when project was over, post-doc using it vented the system and shut everything down.

Went to set it back up today and we're having issues with the turbo pump not ramping up. Rough pump seems to be working properly, no signs of a leak (plugged MS interface) - when powering up the MS it says "System vented" and if we select Pump Down, it starts up and we hear the turbo kick in, goes to about 30% speed then starts dropping down towards 0, all within 2-3 minutes. Checked vent valve, analyzer door seal, pressing while pumping down but somehow this seems to me to be indicative of something different than a large leak (the quick turbo pump speed drop-down), no?

Attempting to pump down through ChemStation, get the message "Pump Down error: MS status fault 400" and "Difficulty with the fan. The high vacuum pump is not ready. The system is in VENT state (high vacuum pump off)". Took the cover off and the fan seems in front of the turbo seems to be running fine and if we blow air over the top rotor of the turbo pump, it seems to spin properly...

Any suggestions would be appreciated.
I had this problem. There are two fans. One cools the turbo pump and one cools the electronics. Both have rpm indicating leads. If either fan is stopped or are still spinning but outside the rpm limits you will get that fault. They run about $155 each. They are easy to replace. I got mine from full spectrum analytics (720)482-1408. Mine are 24V from the label....
Panaflo DC brushless 3GO4CW-1A Model FBA12G24H DC24V 0.3A
If you can match that spec exactly they may be cheaper But I could not find any and I am unsure what rpm limits the 5973 hardware is looking for.

EDIT: I just checked my instrument log. That was 4 years ago. The one in my electronics drawer was frozen. I don't remember if the fans were identical so you had better check the labels on both. FSA billed them as two different fans $155 each but I only kept one of them. So, I think those specs were for the turbo pump fan on the front of the unit. I replaced it and got no joy and then it turned out to be the electronics drawer fan.
LALman wrote:
I had this problem. There are two fans. One cools the turbo pump and one cools the electronics. Both have rpm indicating leads. If either fan is stopped or are still spinning but outside the rpm limits you will get that fault. They run about $155 each. They are easy to replace. I got mine from full spectrum analytics (720)482-1408. Mine are 24V from the label....
Panaflo DC brushless 3GO4CW-1A Model FBA12G24H DC24V 0.3A
If you can match that spec exactly they may be cheaper But I could not find any and I am unsure what rpm limits the 5973 hardware is looking for.

EDIT: I just checked my instrument log. That was 4 years ago. The one in my electronics drawer was frozen. I don't remember if the fans were identical so you had better check the labels on both. FSA billed them as two different fans $155 each but I only kept one of them. So, I think those specs were for the turbo pump fan on the front of the unit. I replaced it and got no joy and then it turned out to be the electronics drawer fan.


Can you give me a bit more information on how you accessed the electronics drawer and its fan?

Thanks!
When you pull off the cover of the 5973, you can see the fan blowing upward. A bit of it is directed against the sideboard by the cowling on the sideboard. If you don't feel a small breeze from that fan, that is probably the problem.

With the power OFF; make sure its OFF and unplugged. The high voltage can kill you.
you can remove the side panel (left side as you face the front) and under that is a bare brushed steel panel that is held on by friction and EMF shielding. Remove that and the fan is accessible. Looking at mine, it looks like it is held in place by plastic peg gromets. If you pull them upward by about a quarter inch, from above, they relax the expansion grip on the fan. You should be able to pull gently down on the fan and bring it out. The fan has a speed sensor lead so you need an exact replacement or the MS electronics will conclude the fan is defective and give you the same fault.
LALman wrote:
When you pull off the cover of the 5973, you can see the fan blowing upward. A bit of it is directed against the sideboard by the cowling on the sideboard. If you don't feel a small breeze from that fan, that is probably the problem.

With the power OFF; make sure its OFF and unplugged. The high voltage can kill you.
you can remove the side panel (left side as you face the front) and under that is a bare brushed steel panel that is held on by friction and EMF shielding. Remove that and the fan is accessible. Looking at mine, it looks like it is held in place by plastic peg gromets. If you pull them upward by about a quarter inch, from above, they relax the expansion grip on the fan. You should be able to pull gently down on the fan and bring it out. The fan has a speed sensor lead so you need an exact replacement or the MS electronics will conclude the fan is defective and give you the same fault.


Thank you - I figured it out later this morning but it's good to have the info written out there for the next people who run across the issue. The fan in the electronics compartment was in fact not spinning, but when I unplugged/replugged it (after taking it out), it started up again. I was then able to pump down normally, but I think I might still replace the fan, since it seems it cause some issues later down the road. Thank you so much for the help!
Its just a matter of time till it fails out of the rpm spec if its slowing down. Copy out the specs on the fan and start looking for a replacement.
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