[labnetwork] MDA System 16 service

[John Shott]

Michael:

While I don't really know of a source that still services these devices, 
I do have a couple of thoughts:

1. The institution with which I was formerly affiliated took a MDA 
System 16 out of service in January 2012.  Last I knew ... as of late 
last year ... it was still sitting around in the basement.  While it has 
not been in service since January 2012, it was fully functional at that 
time.  You might want to contact Mary Tang or Carsen Kline at Stanford 
to see if they would ship all or part of it up the coast to you to see 
if that would get you over your short term need.  Of course, I can't 
guarantee that they still have it or that they would be willing to part 
with it ... but it's hard to imagine what plans one would have for such 
a piece of equipment.  It was used for 16 channels of hydride detection.

2. Have you at least checked the main power supplies for ripple with 
either an oscilloscope or a combination of AC and DC voltmeters?  Many 
"vintage" pieces of equipment with simple, brute-force power supplied 
develop "bizarre" symptoms as their electolytic capacitors dry out and 
lose the ability to store a charge.  I've brought many pieces of 
equipment back to life ... even without circuit schematics ... by 
looking at the ripple on the supposedly DC supplies and replacing two or 
three electolytic capacitors.  I expect that a number of the other 
members of this community with extensive equipment diagnosis experience 
... which sounds better than saying "old timers" ... will agree that 
they have solved many equipment problems in old equipment by simply 
replacing the tired, old main electolytic capacitors in the DC power 
supplies.  While you may be well beyond this stage in your own 
diagnosis, I would at least make sure that your problem could not be 
solved by replacing $10 worth of electrolytic capacitors. Of course,  I 
should add the appropriate caution (which is not needed in your case) 
that you need to exercise caution anytime you have the cover off a piece 
of electronic equipment with 120 VAC exposed ... particularly given the 
fact that if you are probing the main DC supply your probes will be 
dangerously close to the live, mains voltage.  Note:  my guess is that a 
few 10s of mV is acceptable ripple ... but anything over a volt of 
ripple is certainly problematic assuming that this piece of equipment 
used either 24VDC or 15VDC supplies.

Good luck,

John

On 8/30/2016 5:37 PM, Michael Khbeis wrote:
> Dear Colleagues
>
> We are replacing our MDA system 16 in the next 6-8 weeks and are 
> having reoccurring glitches where the MDA loses track of our hydrides 
> monitoring module. This of course triggers a fault in our HPM panel. 
> Does anyone have a point of contact for parts/repair of these legacy 
> systems? We need to limp along for just a few more weeks.
>
> Gratefully,
>
> Dr. Michael Khbeis
> Washington Nanofab Facility
> University of Washington
> Fluke Hall, Box 352143
> (O) 206.543.5101 <tel:206.543.5101>
> (C) 443.254.5192 <tel:443.254.5192>
> khbeis at uw.edu <mailto:khbeis at uw.edu>
>
>
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