Jumpers on the board of a HP 5971A Mass Spec.

[LtStorm]

Hey, just signed up here after plodding around the site for a while. I've spent the past few months working on an old Hewlett-Packard 5971A MS to try to get it back in working order. So far we've made great progress by cleaning the source, quadrupole, and replacing the electron multiplier, as well as updating to a slightly newer version of the ChemStation software we use with it (version A.00.00 to C.02.00...), but we're still having a few problems.

So, we've had "excess signal" problems we still haven't solved when we try to autotune the machine. The autotune seems to go fine, but then right at the end it opens the PFTBA valve a second time, as it's presumably trying to do a last spectrum scan, but this causes it to bomb out with the "excess signal" error.

So, my actual question is; we've noticed a jumper on the mainboard of the MS labeled as "Excess Signal: Enable/Disable." It's currently set to Enable, and we're assuming it would allow us to select whether or not the machine cuts everything off when it detects an excess signal. What I'm we're wondering now is what the effect would be of Disabling the jumper. Mostly whether it would risk damaging anything (in the short term, that is) from being switched over. And further, what effect switching it would have on our attempts to autotune.

Anyone have any experience with this machine, or this same issue on another machine, that could offer advice?

We're preparing to start really tinkering with manual tuning it, but if this would get the autotune running properly it could save us some trouble. Wouldn't be so annoying if it didn't look like the autotune ran fine, then it bombed out after it finish and dropped all its work.

Thanks in advance for any help.