Re: time-nuts Digest, Vol 233, Issue 9 > > ---------------------------------------------------------------------- > > Message: 1 > Date: Sun, 10 Sep 2023 17:19:07 +0100 > From: David Kirkby <drkirkby@kirkbymicrowave.co.uk> > Subject: [time-nuts] Power supply buzzing in HP 58503A GPS receiver. > To: "time-nuts@lists.febo.com" <time-nuts@lists.febo.com> > Message-ID: > <CAGweRBcbe114D+OvYq2QrgofmbTtc1OHRsPmZdGDcBe0+nFmHQ@mail.gmail.com> > Content-Type: text/plain; charset="UTF-8" > > After about 6 months of being powered off, I switched on my GPS receiver > yesterday. The PSU is buzzing quite loudly. Sound file at > > <https://www.kirkbymicrowave.co.uk/noisy-PSU-in-HP-58503A-GPS-time-and-frequency-standard-recorded-10th-Sempember-2023.m4a> I could hear your voice, but not the buzzing. I have two suggestions. First, get a mechanic's stethoscope, and poke around. Here is one: .<https://www.amazon.com/Lisle-52750-Stethoscope-Kit/dp/B0015DLMOO/ref=sr_1_5?keywords=automotive%2Bstethoscope&qid=1694442384&sr=8-5&th=1> Second, I use a spectrogram app on my iPhone, and it would tell one a lot about what's going on. The app is Spectrogram. The following may be a later release> .<https://apps.apple.com/us/app/spectrogram-pro-with-super-smooth-60hz-update/id415301721> Joe Gwinn

Guys, Having worked on a number of switching power supplies I have found that if it is making a squealing noise that is quite audible that is because the supply is working into a short circuit. It is shutting down and restarting at an audible rate. This could be an external short or a short internal to supply itself. I suggest making a few Ohm meter checks. Mike Bafaro WA9ZEO -----Original Message----- From: Joseph Gwinn via time-nuts <time-nuts@lists.febo.com> Sent: Monday, September 11, 2023 9:38 AM To: time-nuts@lists.febo.com Cc: Joseph Gwinn <joegwinn@comcast.net> Subject: [time-nuts] Re: Power supply buzzing in HP 58503A GPS receiver. Re: time-nuts Digest, Vol 233, Issue 9 > > ---------------------------------------------------------------------- > > Message: 1 > Date: Sun, 10 Sep 2023 17:19:07 +0100 > From: David Kirkby <drkirkby@kirkbymicrowave.co.uk> > Subject: [time-nuts] Power supply buzzing in HP 58503A GPS receiver. > To: "time-nuts@lists.febo.com" <time-nuts@lists.febo.com> > Message-ID: > <CAGweRBcbe114D+OvYq2QrgofmbTtc1OHRsPmZdGDcBe0+nFmHQ@mail.gmail.com> > Content-Type: text/plain; charset="UTF-8" > > After about 6 months of being powered off, I switched on my GPS > receiver yesterday. The PSU is buzzing quite loudly. Sound file at > > <https://www.kirkbymicrowave.co.uk/noisy-PSU-in-HP-58503A-GPS-time-and-frequ ency-standard-recorded-10th-Sempember-2023.m4a> I could hear your voice, but not the buzzing. I have two suggestions. First, get a mechanic's stethoscope, and poke around. Here is one: .<https://www.amazon.com/Lisle-52750-Stethoscope-Kit/dp/B0015DLMOO/ref=sr_1_ 5?keywords=automotive%2Bstethoscope&qid=1694442384&sr=8-5&th=1> Second, I use a spectrogram app on my iPhone, and it would tell one a lot about what's going on. The app is Spectrogram. The following may be a later release> .<https://apps.apple.com/us/app/spectrogram-pro-with-super-smooth-60hz-updat e/id415301721> Joe Gwinn _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe send an email to time-nuts-leave@lists.febo.com