Chromatography Forum

Please can someone help with this problem please?
Our HP 5973 MS, which has been sitting in pieces for a while has recently been cleaned and then reassembled. It has two new filaments installed. This was fine and tuned fine. A blank sample of hexane was run by a student and gave a reasonable TIC. A second injection was carried out and nothing. No peaks no trace on the screen.
I then tried tuning and water/air checks and all I get is noise with count numbers in the single figures but as you run the auto tune it does pick up the occasional peak with a count in the hundreds. The the tune fails and gives the error message “error: Tune action stopped: Gain and offset = 0 and peaks are too narrow”
When I have tried running a sample using a previous stune file I get noise with counts in the range of hundreds. But no trace with the atune file that was ok previously.

The EM voltage when trying to run a sample is 1765.
Any help and/or advice greatly appreciated.

Is there PFTBA in the tune vial?
Try another type of tune such as s tune to see if it will tune.

Is there PFTBA in the tune vial?
Try another type of tune such as s tune to see if it will tune.

Tried other tunes. Even if there was none surely I would get a trace when running sample though?

Try restoring a previous tune file which looks good and save it as the tune file.

Or // as your instrument has been sitting out for a while, make sure that all the wires are where they are supposed to be (in the msd), bake the MSD and try retuning. If this doesn't work then try to restore a good previous tune file.

Or // as your instrument has been sitting out for a while, make sure that all the wires are where they are supposed to be (in the msd), bake the MSD and try retuning. If this doesn't work then try to restore a good previous tune file.

As I say it was working and did run some toluene in methanol samples previous to what I said before. So I think the wires are ok. I tried an old tune file, that didn't work and have now checked the PFTBA and purged the valve afterwards. Which made no difference.

Could this be a multiplier problem?

I ask this because the noise only gives a count in single numbers but with the occasional peak flashing up during an attempted tune but they only have a count in the hundreds.

Or // as your instrument has been sitting out for a while, make sure that all the wires are where they are supposed to be (in the msd), bake the MSD and try retuning. If this doesn't work then try to restore a good previous tune file.

Sily question, how do I bake the MSD?

OK doing that now.

Anyway, I am going home to stick my head in the oven.

Do you here a click from the pftba solenoid valve, it could have failed so the the msd is not getting its pftba.

We had a power supply to the HED go bad a while back. I can't remember now all the specifics to the symptoms we were having but this sounds similar. We also had a main/side-board go bad on the '73's a couple times. This caused unpredictable issues. Not just all signal vs. no signal. I hope neither of these are the problem for you as they tend to get pricey to repair.