Is this a 5971 or 5972 MSD? Connecting ionization gauge?

[lespaul]

Hi everyone,

I'm finally setting my GC-MS (HP5890/5972) system here in our lab.

The top cover on the MSD states its a 5972, however when I remove it there is a sticker saying its a 5971. Does anyone know how to tell the difference between a 5971 vs 5972?

Here are some photos of my system so you get a better idea: https://imgur.com/gallery/XKvUiuw

My second question, is how do I connect my ionization gauge. We currently have a 59822B (without the cable) and I'm wondering if it will work with my 5890/5972. I've seen other systems with this same gauge so my guess is it will work. Or do I need the (newer) 59864 ionization gauge? The size of the tubes on the MSD are vastly different, hence my confusion.

Any assistance with this would be greatly appreciated.

Thanks,
A GCMS newbie

[James_Ball]

I can't open the image at work, but the 5971 had a one piece cover and to get to the analyzer you had to remove everything facing forward and to the left, it exposed all the analyzer and electronics areas, the 5972 had a two piece cover where just the top would lift off allowing access to the analyzer and you had to remove the lower portion to have access to the electronics and gauge tube area.

If you are looking at the sticker on the top board of the analyzer it could say either since the analyzer itself was interchangeable. The difference is in the electronics, mostly the main board and the power supply. Any 5971 that received a new power supply after the 5972 came out got the 5972 power supply.

I am not sure on the ion gauge tube, the 5971 came with the huge one just like on the 5970, but at some point they switched to the smaller tube but I am not sure if the cables were the same.

[LALman]

Hi everyone,

I'm finally setting my GC-MS (HP5890/5972) system here in our lab.

The top cover on the MSD states its a 5972, however when I remove it there is a sticker saying its a 5971. Does anyone know how to tell the difference between a 5971 vs 5972?

Here are some photos of my system so you get a better idea: https://imgur.com/gallery/XKvUiuw

My second question, is how do I connect my ionization gauge. We currently have a 59822B (without the cable) and I'm wondering if it will work with my 5890/5972. I've seen other systems with this same gauge so my guess is it will work. Or do I need the (newer) 59864 ionization gauge? The size of the tubes on the MSD are vastly different, hence my confusion.

Any assistance with this would be greatly appreciated.

Thanks,
A GCMS newbie

I don't think those first pics resemble a 5971. The triode tube and tune valve have separate connections with the vacuum chamber and that is not what I see on my 5971 unit. My unit looks exactly like your confirmed 5971.

My 5971 setup looks like that last photo where the tune valve and the vacuum gage all t off of the same stem. Mine originally came with the big vacuum tube and HP 59822B gauge. But I found out I could use a triode tube and the 59864B ionization gauge (the tube fitting will take both). So, I switched because I had an extra 59864B. Long story but had to find a new one fast and then was able to repair the old one. You do need the new cable. But its not too expensive ~$110.

[benhutcherson]

As said, the "small" triode type gauge as used on the 5973 will fit even a 5971. I still have the "big" gauge on my 5971 at work, but service one that has that type of gauge. If mine ever goes out, I'll probably put the triode type gauge on it as the big gauge can-quite literally-be painful for things like accessing the cal gas vial(people who have heard me talk about it can usually spot when I've had to get at one because of the particular pattern of scratches it leaves on my hand).

I wouldn't get too concerned about the quads having a 5971 label on them. I'm pretty sure I've even run across documents that described how to upgrade a 71 to a 72 in the field. There's honestly not a ton of difference between them.

[James_Ball]

As said, the "small" triode type gauge as used on the 5973 will fit even a 5971. I still have the "big" gauge on my 5971 at work, but service one that has that type of gauge. If mine ever goes out, I'll probably put the triode type gauge on it as the big gauge can-quite literally-be painful for things like accessing the cal gas vial(people who have heard me talk about it can usually spot when I've had to get at one because of the particular pattern of scratches it leaves on my hand).

I wouldn't get too concerned about the quads having a 5971 label on them. I'm pretty sure I've even run across documents that described how to upgrade a 71 to a 72 in the field. There's honestly not a ton of difference between them.

Don't the factory 5972s use a large O-ring similar to the 5973 instead of the large flat gasket to seal the top plate to the analyzer? That would be another way to identify which model it is.

As Ben mentioned, many of the 5971s were upgraded to 5972s in the field, which gave the ability to adjust the filament current and a more reliable power supply.