Hi Brian,

we had a similar problem a few years ago on a Delta S. The fuse had to 
be replaced after every black out (these things always happen during the 
  weekend or after midnight...). After replacing we had to shut down the 
Delta S completely (main switch, all pumps off!) and had to wait for few 
seconds. Only replacing the fuse and switch on the Combivac did not 
help. It seemed to me that the Combivac needed a "reset".

Before I figured out the trick, I phoned around to find someone to 
repair the unit. You may contact the manufacture of the Combivac. I 
think it was Leybold vaccum GmbH, Cologne, Germany, now: 
<http://www.oerlikon.com/ecomaXL/index.php?site=VACUUM_EN_services_contact>

Other companies from the vacuum business having experience with Finnigan 
machines may also worth a try (all in Germany):
<http://www.mascom-bremen.de/html/en/0/index.html>
<http://www.masstech.de/en/>

regards,
Robert

Brian N. Popp wrote:
> Hi All
> 
> We have had some problems with our MAT 252. Roger Husted has helped us 
> significantly with the problem but we have now run into an equipment 
> supply wall.
> 
> The Problem
> 
> Hawaiian Electric Company gave us a belated Christmas present the other 
> night when the entire Island of Oahu lost power, which plunged our 
> future president's vacation rental and our laboratory into complete 
> darkness. Everything but the MAT 252 more-or-less bounced back. On the 
> 252 none of the fore vacuum LED lights on the front panel are 
> illuminated but all high vacuum lights remain on and the analog gauge 
> provides no reading regardless of which button is depressed. We are 
> unable to turn on the ion source and high voltage. On the other hand, 
> all three turbo pumps are working (green lights on TPH controller 
> illuminated and we can hear them spinning/singing).
> 
> The Culprit
> 
> We suspected a blown fuse/circuit and Roger suggested first checking the 
> Combivac IT 251 - as usual he was on the mark. Caution - the mains fuse 
> on the Combivac IT 251 when blown still can show resistance so it took 
> me a week to recognize that we had a blown fuse (I hope I will not make 
> that mistake again). Any new fuse that is installed promptly blows when 
> the Combivac is plugged in.
> 
> The REAL Problem and Requests
> 
> Finnigan is out of stock and there is no anticipated time when the 
> Combivac IT 251 stock will be replenished. I assume this means that 
> Finnigan cannot get hold of any new or rebuilt units.
> 
> Does anybody know 1) a company that will rebuilt a LH Combivac IT 251, 
> 2) if wiring schematics are available for this unit, or 3) if used ones 
> are available (I checked eBay already)? Any other suggestions are welcome.
> 
> Apparently there is a fail safe mechanism inside the Combivac IT 251 
> that shorts (and stays shorted) if, for example, there is a power surge. 
> Unfortunately, our electronics folks could not see anything obvious when 
> it was opened.
> 
> I appreciate any help that folks can give us and will post results when 
> we resolve the issue. The Combivac IT 251 is also used on 
> Delta-S/DeltaPlus with differential pumping.
> 
> Thanks much and aloha.
> 
> Brian
> 
> Brian N. Popp
> Department of Geology and Geophysics
> 1680 East-West Road
> University of Hawaii
> Honolulu, Hawaii 96822
> Phone - (808) 956-6206; Fax - (808) 956-5512
> E-mail - [log in to unmask]
> Web page - _ http://www.soest.hawaii.edu/GG/FACULTY/POPP/bpopp.html_