Top Board - is physically mounted to the top stainless steel manifold plate and is primarily responsible for the RF power generation and peak control, peak width and peak location.  The  Top Board seems to be the most fragile board of the hp 5971 msd and hp 5972 msd.  Non-existing or inconsistent peaks are the main clues to a bad top board.  While RF power generation and control is a complicated engineering application, it is a board that can be relatively easy to repair.  Send it to us and we'll troubleshoot it and repiar (or replace) it for you.

I/O board - is otherwise commonly known as the "SmartCard".   The smartcard is the rectangular board to the left of and plugged into the Main board.   There are several versions of Smartcards and (for the hp 5971 and hp 5972) after the Smartcard I are all backwards compatible. The  Smartcard I can be identified by "Discrete" memory chips soldered directly to the board.  All Smartcards NEWER than the Version I, have memory in the form of RAM Sims, much like the RAM memory SIMS found in your desktop personal computer.  Go to our page:  http://cssco.com/smartcard-id  for easy id.  The Smartcard is the "Brain" of the mass spectrometer and is in fact a mini computer.  It has several micro processors and lots of memory.  It is responsible for the HPIB communication, control of the mass spectrometer scanning, data acquisition, data buffering and data manipulating.  Troubleshooting of this board is limited to "Initializing" (testing HPIB communication ... SCINIT at the comman line). hard reset - for newer boards,  and "Profiling" in manual tune.  Profiling with a bad Smartcard (in manual tune) can identify a memory SIM error.

Main Board - is the large SQUARE board mounted on the front of the electronics chassis (right side board if you are facing the two boards).  Most of the control functions are placed on the main board and there is little to trouble shoot.  Testing of the DC power supply can be done by probing the test points on the main board.  (See our blog entry for troubleshooting the DC Power Supply)   This is the main mechanism used to troubleshooting the DC power supply.    However, a bad main board can  "Pull Down" the DC power supply.  Disconnecting the DC power supply from the main board and testing the power supply directly can help troubleshoot a bad main board.  It never hurts to remove all connectors (power off of course) and make sure none of the pins of the connectors or recipticals are bent.  We've seen that happen !  Other than that - remove and replace a bad or suspected main board with a known working main board, or send it to us for testing. 

Power Distribution Board / Vacuum Controller Board

Power Distribution Board (PDB) - is both the primary distribution node for the the incoming power and the board that starts and controls the diffusion pump.   The PDB is stuffed under the manifold, behind the electronics chassis (sheet metal where main board and I/O board are mounted).  It is rare that this board dies, but it does happen. 

The beauty of this board is that it fully controls the diff pump with or without the PC and Chemstation up and running.  Get the manifold under vacuum and power on the MSD.  This board will take over and turn on the diff pump when the vacuum is low enough and provide the "Diff Pump On and Hot" signal when appropriate.  The board also provides a red led to indicate that the diff pump is powered on and running.  You can see the red led through a one-half inch hole in the chassis back behind the smartcard near where the power cord comes in. 

There are only 5 boards (assemblies) in the HP 5971 and HP 5972 MSD.  Over the next few blog entries we will assist you in troubleshooting each of these modules.

O-Rings for the HP/Agilent can be purcased directly from Agilent  but they can be rather expensive.  Now that the HP 5972 and HP 5971 is so old, finding the right o-rings can be problematic.

If you have an HP 5971 or Agilent 5972 MSD and you can't get the diff pump to turn on there are only a few possibilities.  1)  You have a massive leak and the diff pump controller board won't allow the diff pump to turn on.  2)  The DC power supply in the MSD is dead and can't run the pump controller board,   and 3)  The diff pump heater is dead.  

HP 5971 and HP 5972 Mass Spectrometers have difussion pumps and on the frame of the diffusion pump are two sensors.  A   Too Cold Sensor, the bottom (white wires) and the Too Hot Sensor, the top (red wires).   The signal from the sensors report to the startup and run electronics of the Power Distribution Board.

If your Autosampler has run thousands of samples like mine, it might be a little sluggish these days. Here's how to PM your Autosampler system and maybe get another six to twelve months of continued use from it.

Mass Spectrometry is a analytical technique that makes and sorts molecules based on mass.  In order to make and move ions, a sufficient vacuum is required.  In order to make a good vacuum, GCMS Mass Spectrometers need o-rings.

Most o-rings, once put in place are never disturbed and are good for years but eventually they need to be attended to.  Most are easy to get to and are inexpensive and can just be replaced.  Such as for the rough pump, diff pump, ion gauge, calibration valve, etc...