Chromatography Forum

We have a HP GC/MS 5890/5972 not being used frequently. About 6 weeks ago, we had a power failure during weekend, and the system turned on by itself when the power was back. However, the 5972 MSD front panel lights were off and the diffusion pump was cold, although rough pump and diffusion pump fan were working. Gauge controller gave me a pressure around 5 millitorr and I was pretty sure that the rough pump line wasn't leaking. I left the pump running that day and thought to check diffusion pump later, but when I came to work the next day, the MSD front panel power lights were on, and diffusion pump became warm. I thought maybe the system had to be turned on in a certain sequence, and I had to let the rough pump working for a while before the diffusion pump could start.

Unfortunately, the same problem happened once again two weeks ago. But this time, no matter what sequence I shut down and turned on the system, I couldn't bring MSD back on. I changed rough pump oil and diffusion pump fluid, the pressure from gauge controller was still around 5 millitorr. I opened the top cover of MSD and found the ion gauge was on. I've contacted Agilent, at least two tech support reps told me that I may have either mainboard or power supply down. But, if the power supply for MSD isn't working, should the ion gauge be on?

I'm going to check diffusion pump cable/plug and MSD power supply, but before I mess up with everything, I hope that maybe someone out here have experience on this old model and could give me some advice. Is it really a problem from mainboard? If so, is there any way that I can fix it? Are there any other reasons that make MSD off?

I don't want to just throw the machine out of window. Any comments are highly appreciated!

I have the same setup minus the diffusion pump. The power suppy of your MS and Gauge control should be different. Did you check the breaker? I had something similar occur, it required replacing the motherboard...if I remember correctly...the cause was traced to an electrician haphazardly flipping breakers. Sounds to me like you may the the assistance of a service technician. Good luck.

Thank you, ydm27. I checked the main board power supply following the hardware manual. All the voltages were about half of required. I'm going to check the power distribution board and cables. do you remember where the breaker is? If the main board is totally broken, I don't know if we can afford to buy one.

I can't help you on the reasoning for only getting half of the voltage. As for the breaker, check at the main breaker box in your lab. Ideally, it would have been label by an electrician at installation. In my case, each GC/MS has a dedicated breaker. Fortunately, I did not have to purchase the board so I cannot give you an estimate on the cost. I would suggest a search for company that refurbishes MS's. I was referred to and now use Alpha Omega Technologies - http://www.aoti.net/ - Their customer service is great and their technicians are very knowledgeable.

Thanks again. I called Alfa Omega and was told main board OK, but power supply board need to be replaced. Now waiting for the decision...

Sheedo,

Just serviced an 5971 MS with a very similar problem, only half the voltages. There are two power boards, the power supply and power distribution. One is basically a transformer board and the other is a switching supply. About a $1000 dollar difference between them. I my case it was the switching supply that was bad. Another possible vendor, MLS Technologies (on the web.)

Best regards.

Thank you AICMM.
Just want to follow up with our HP MSD 5972. I got the new power supply board and put it on this afternoon. All the voltages from test points reach the value they're supposed to be. Now, diffusion pump is on and the vacuum is lowered to about 2.3 mtorr. Everything is working fine! I will tune the MSD tomorrow.
Again, thanks everyone!