I've only worked on the PTS-500s but if this is the same capacitor as they
use in there they can be found at Newark Electronics, mfgr. Nichicon, part
#18K7074 (10,000uf, 25V, axial leads). And again, if it's the same as the
PTS 500, one of them usually carries ~10VDC and the other ~20VDC. If on
either of them the DC voltage is far off, or the AC ripple is more than a
percent or two, they could be the problem and should probably be replaced.
John T.
On Sat, Jun 7, 2014 at 4:02 PM, David H Live <dlive_at_ccrc.uga.edu> wrote:
> 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)
>
>
>
--
JWT
Received on Mon Jun 09 2014 - 08:51:48 MST