Chromatography Forum

Equipment: Agilent GC-MS 5973 - 6890N

Quick question. A few weeks ago, the system was running fine but now after having it shut down for a week or so for software installations, the foreline pump does not fire up when the MSD is powered on. The rest of the system seems to power up just fine because the LCD shows it initializing and everything.

To troubleshoot, I swapped the two fuses in the back of the panel with working fuses from our second MSD and the pump would not fire up. I have moved the pump onto our second GC and it works just fine. Agilent suggests a new board but I wanted to fish for some more things to check before I dive into that repair bill because they usually rush you off to the billing department before going through troubleshooting steps. Thanks!

I assume the foreline pump is what I usually call the rough pump. If the pump works it would seem to be that the GC/MS is not sending power to the plug that the rough pump plugs into. I guess you can get that fixed through Agilent but I think I'd rather just plug the pump into the wall.

Like he said, make sure the pump works by bypassing the MS.

Also, never run that turbo fan without the roughing pump. Can lead to problems.

Hi, I fix this problem all the time--you blew a fuse probably during a storm or power cycle.

You can put an extension cable on the rough pump power cable and plug it into a normal wall outlet in order to keep working. Do not run the turbo w/o rough pump.

Your problem is you blew a fuse on your MSD electronics module. Replacing this is easy, but you have to take off the MS covers, and unplug everything. If you have a contract call Agilent, if you don't feel comfortable doing it don't do it yourself.

While the instrument is vented and powered off take off the side panel/cover. Unplug everything between the sideboard and electronics module. Unplug everything connected to the back of the electronics module. If you are unfamiliar with what goes where take a picture so you can get it back together correctly.

Once everything is unplugged there is a small piece of plastic on top of the power button (on the front of the MS) that you pop out using a flat head screwdriver. There is also a thumbscrew near the end of the analyzer that must be loosened to remove the electronics module. Once those are removed/loose the E-Mod just slides out, be sure to do this carefully so you don't snag any of the cables on the sideboard.

Set the E-Mod on a clean table and there is a cover on each side which you can just pop off using your fingers. There are several fuses, just look for one that is black or obviously blown.

You can get a replacement from Agilent, or probably from a local HW store I don't think its a special fuse.

Thanks very much for your helpful and detailed instructions on the problem and how to access the ac board on the electronics module. It helped out my lab enormously and I appreciate the time you took to reply to the original query.

No problem, this is a very frequent issue but easy enough to solve--hopefully you aren't the last to be helped by the post haha. I recently fixed another one of these last week and had to run out to radioshack to get the fuse (it says on the fuse what kind it is, I think 4 A 240 V.)

When I replaced the obviously blown fuse I turned it on and blew the one next to it, so make sure to get a 4 pack . There are fuses on both sides of the electronics module but the ones you want are clear glass not ceramic.