As Mark Rance points out there is a well known symptom of capacitor failures in the PTS power supplies that results in spikes in the spectrum at 2 times the AC frequency, 120 Hz in the US, and presumably 100 Hz in Europe. This typically manifests itself in a modulation of the PTS output that is often readily observable looking at the output on an oscilloscope. It is difficult to find the exact replacement capacitor from electronic suppliers (I assume PTS must have the particular one custom made for them), however a similar one is available made by Sprague, 11000 uF 25 V, which although physically a little bigger does work in my experience, having made this replacement multiple times on PTS units. You may be able to get an exact replacement from PTS.
David Live
Senior Research Scientist
Complex Carbohydrate Research Center
University of Georgia
315 Riverbend Rd.
Athens, GA 30602
706-542-6262
________________________________________
From: Rance, Mark (rancema) <rancema_at_UCMAIL.UC.EDU>
Sent: Friday, June 6, 2014 3:59 PM
To: Matthias Findeisen
Cc: Ammrl_at_ammrl.org
Subject: RE: AMMRL: PTS repair
Hi,
You might want to check with PTS about a certain capacitor in the power supply - it is a well known issue to them and my understanding is that they typically replace that capacitor when a unit is returned to them for repair. We found that the symptoms of these capacitors going bad could be quite variable and sometimes subtle. Its probably not the source of your problem if you have a relatively new instrument, but for older instruments it is something worth asking PTS about. You can get replacement capacitors from them and instructions about how to replace the capacitors on site.
Mark
Mark Rance, Ph.D.
Professor
Dept. of Molecular Genetics, Biochemistry and Microbiology
University of Cincinnati College of Medicine
231 Albert Sabin Way
Cincinnati, Ohio 45267
e-mail: Mark.Rance_at_UC.Edu
phone: 513-558-0066
________________________________________
From: Matthias Findeisen [matthias.findeisen_at_uni-leipzig.de]
Sent: Friday, June 06, 2014 3:43 AM
To: Ammrl_at_ammrl.org
Subject: AMMRL: PTS repair
Hi folks
does anybody knows, who does repair Synthesizer PTS 620-dual (in Europe)?
Obviously we have 100 Hz spikes in spectra (i.e 10ms spikes in FID).
An electronic professional checked the power supply, but this seems not to
be the reason.
Thanks.
Cheers
Matthias Findeisen
(Univ. Leipzig, Germany)
Received on Sat Jun 07 2014 - 10:02:33 MST