[time-nuts] Re: Power supply buzzing in HP 58503A GPS receiver.

Wed Sep 13 08:54:03 UTC 2023

I am also a lover of hp measurement technology, but I do not have the described frequency and time standard 58503A/B of hp or Symmetricom.
My frequency standards (also rubidium) come from DATUM-Symmetricom, Meinberg and other manufacturers.

To the problem described here in the forum I can give from my experience the tip on the power transformer.

I think the time-nuts fans also have many devices and may be able to give me information on my DATUM-Symmetricom device.

Hello Willo,
yes, my transformer has 230V winding interruption on primary side. Secondary side pin 6-7 has 1.6 ohms, pin 8-9 has 0.3 ohms.
To find the right transformer, I need the low-voltage AC voltages and currents. If your power supply is open again, I ask for measurements or schematic information.
Thanks

MfG
Helmut

-----UrsprÃ¼ngliche Nachricht-----
Von: Wilko Bulte via time-nuts <mailto:time-nuts at lists.febo.com> 
Gesendet: Dienstag, 12. September 2023 22:23
An: Discussion of precise time and frequency measurement <mailto:time-nuts at lists.febo.com>
Cc: Wilko Bulte <mailto:wkb at xs4all.nl>
Betreff: [time-nuts] Re: Power supply buzzing in HP 58503A GPS receiver.

hello Helmut,

Are you 100% sure the transformer is indeed dead? And, in other words, it is not a problem in the DC part 'behind' the transformer like a dead bridge rectifier, bulk cap or pass transistor? Are you certain you have open or short windings on the transformer?

The MPS transformer in my MFS system does not look better than yours, also some corrosion etc. That is not a reason perse for worry, mine works just fine. 

Just my â‚¬0,02..

MfG,
Willo

> On 12 Sep 2023, at 21:29, jung.schorndorf--- via time-nuts <mailto:time-nuts at lists.febo.com> wrote:
> 
> ï»¿Hello time and frequency standard owners,
> 
> a similar problem, tap Power Transformer ...
> 
> my power supply MPS in the device MFS (Modular Frequency Systems) from EFRATOM-DATUM_SYMMETRICOM has plagued me with a hum noise
> for many months. When it stopped working and I opened it, the power transformer turned out with a turn damage (photo) and totally corroded - in laboratory conditions!
> I can also operate the device externally with 24V DC. However, I would like to replace the unavailable original transformer,
> but have not seen any transformer data (U, I) because missing documents. Because winding interruption I can not measure it either.
> In the data sheets I only find different DC data (20.5V DC, 23-33V DC, 40 W, 55 W ??).
> The transformer had 2 AC outputs on the secondary side.
> I have only a few inserts and do not need the theoretical 200 VA max. power.
> Does anyone in the US still have circuits? The German branch has nothing more.
> 
> Thanks for info
> Helmut
> 
> 
> 
> 
> -----UrsprÃ¼ngliche Nachricht-----
> Von: Adrian Godwin via time-nuts <mailto:time-nuts at lists.febo.com> 
> Gesendet: Montag, 11. September 2023 10:10
> An: Discussion of precise time and frequency measurement <mailto:time-nuts at lists.febo.com>
> Cc: Adrian Godwin <mailto:artgodwin at gmail.com>
> Betreff: [time-nuts] Re: Power supply buzzing in HP 58503A GPS receiver.
> 
> I don't have a 58503A but I do have some RFTG-u which I understand to be
> quite similar. I'm not sure if that extends to the power supply
> architecture. Do they just have an integral mains power supply before a
> Lucent DC-DC converter ?
> 
> I had one fail due to a tantalum capacitor downstream of the DC-DC
> converter. It didn't shut down the DC-DC but it did cause it to take a
> heavy incoming current resulting in the literal melting (and subsequent
> mains breaker cutout) of a cheap power brick that was being used to provide
> 24V.
> 
> So, the mains part of the supply might be running at an overcurrent without
> shutting down.
> 
> Replacing the tant (and the power brick) fixed it without any other damage.
> 
> 
>> On Mon, Sep 11, 2023 at 5:31â€¯AM Ed Marciniak via time-nuts <
>> mailto:time-nuts at lists.febo.com> wrote:
>> 
>> I donâ€™t have one of those units, but switching power supplies under
>> certain load conditions can have subharmonic oscillations that happen to
>> fall in the audible frequency range. Absent an overload from a shorter
>> capacitor or similar, Iâ€™d take a hard look at whether there are capacitors
>> that no longer meet their ESR specifications and/or have cold solder joints
>> effectively removing them from the circuit.
>> ________________________________
>> From: Wilko Bulte via time-nuts <mailto:time-nuts at lists.febo.com>
>> Sent: Sunday, September 10, 2023 3:57:06 PM
>> To: Discussion of precise time and frequency measurement <
>> mailto:time-nuts at lists.febo.com>
>> Cc: Wilko Bulte <mailto:wkb at xs4all.nl>
>> Subject: [time-nuts] Re: Power supply buzzing in HP 58503A GPS receiver.
>> 
>> Wild guess here, this sounds to me like a coil "whistling". Maybe there is
>> an inductor or transformer  that lost its potting compound, or has somehow
>> come loose from its fittings?
>> 
>> best,
>> Wilko
>> 
>>> On 10 Sep 2023, at 21:24, David Kirkby via time-nuts <
>> mailto:time-nuts at lists.febo.com> wrote:
>>> 
>>> ï»¿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 thought that one of the 100 uF 400 V capacitors after the rectifier
>> might
>>> be bulging, although I was unsure. The capacitance measures okay, and the
>>> ESR is below that of anything I can buy that will physically fit. Same
>> for
>>> the 47 uF 400 V capacitor. These were both measured out of circuit, using
>>> an HP 4284A LCR meter at 120 Hz. I chose that, despite the fact that we
>>> have 50 Hz mains here in the UK, as data normally seems to be provided on
>>> capacitors at 120 Hz.
>>> 
>>> Has anyone experienced this before? I believe that someone wrote here, or
>>> might have been elsewhere, that the GPS receiver was pushing one of the
>>> supplies to the limit, and another one was not loaded enough. I know
>> there
>>> was some mention of converting it to run from a linear supply, although I
>>> think that would be physically larger, so not fit in the case.
>>> 
>>> 
>>> --
>>> Dr David Kirkby Ph.D
>>> Kirkby Microwave Ltd
>>> Email: mailto:drkirkby at kirkbymicrowave.co.uk
>>> Web: https://www.kirkbymicrowave.co.uk/
>>> Telephone 07910 441670 (UK) or +44 7910 441670 (international)
>>> Registered in England and Wales, company number 08914892.
>>> Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, Essex, CM3
>> 6DT
>>> _______________________________________________
>>> time-nuts mailing list -- mailto:time-nuts at lists.febo.com
>>> To unsubscribe send an email to mailto:time-nuts-leave at lists.febo.com
>> _______________________________________________
>> time-nuts mailing list -- mailto:time-nuts at lists.febo.com
>> To unsubscribe send an email to mailto:time-nuts-leave at lists.febo.com
>> _______________________________________________
>> time-nuts mailing list -- mailto:time-nuts at lists.febo.com
>> To unsubscribe send an email to mailto:time-nuts-leave at lists.febo.com
> _______________________________________________
> time-nuts mailing list -- mailto:time-nuts at lists.febo.com
> To unsubscribe send an email to mailto:time-nuts-leave at lists.febo.com
> <MPS_8.jpg>
> <MPS_1.jpg>
> _______________________________________________
> time-nuts mailing list -- mailto:time-nuts at lists.febo.com
> To unsubscribe send an email to mailto:time-nuts-leave at lists.febo.com
_______________________________________________
time-nuts mailing list -- mailto:time-nuts at lists.febo.com
To unsubscribe send an email to mailto:time-nuts-leave at lists.febo.com