1100 MSD Power problem

[PierceDublin]

Hi,

Picked up a second-hand an 1100 LC/MSD for our lab last year and it was worked really well until we turned it off and then tried to turn it on again. It just didn’t come back on. Not a light, not a sound. Mains power supply and power connections were checked and found to be fine. Anyway sent it back to the company we bought it from and they replaced the analyser board and the power module. They also suggested that the roughing pump should be powered directly from the mains, and not via the MSD, which we did. Got it back and it worked well until this morning when we came in and found that the LED light on the front was red. The diagnostic page indicated “high vacuum off” even though the turbos seemed to be working. Anyway ended up turning it off again and when turned on again nothing happened. I’m at a loss to explain what’s going on. Again, mains power supply was checked and found to be fine. Plug, fuse and wiring from mains to machine were also checked and found to be OK as well. Rod connecting front switch to the switch on the power unit at the back is also OK. Any suggestions as to why there would be a total power failure in the machine even though power is going into it would be most appreciated. We’ve been running a 5973MSD for 14 years and it has never given us a problem like this.

Thanks in advance,

P.

[lmh]

I'm not sure this is going to help, but I think your current problem is totally unrelated to what happened before. Before, you had no lights, no sign of life whatsoever, and the main power supply had gone. It's slightly under-specced, and can easily be destroyed if anything (roughing pumps!) draws an excessive current. That's almost certainly why your supplier suggested running the rough pumps as stand-alone. Also, it's embedded at the back of the instrument under everything else and you have to practically take the whole thing apart to change it...

If you've got a light (red!) then this time the power is fine. There are other reasons why high vacuum might appear to be missing, for example if the ion guage has failed (but I don't know if they often do in 1100 MSDs, or whether the turbo pumps continue to run if it fails).