[time-nuts] HP 58503B PSU replacement

[George Atkinson]

Hi Dave,
Thanks for the info. I've already built the analogue supply and it's working fine. It's interesting that even that 55W supply is operating near it's -15V limit with the 58503A and the minumum load requiremen on th main +5V rail is not quite met either.

Robert.


> On 08 November 2018 at 21:43 "Dr. David Kirkby" <drkirkby at kirkbymicrowave.co.uk> wrote:
> 
>     On Thu, 8 Nov 2018, 14:53 George Atkinson via time-nuts < time-nuts at lists.febo.com mailto:time-nuts at lists.febo.com wrote:
> 
>         > > Last month I was at the UK “National” hamfest and in the flea market area a seller had a HP 58503B for sale. It was missing the cover and power supply (AC mains version)including mounting. However it was only £3 (<5$) so it was a no-brainer to buy it. Research shows that PSU failure is fairly common on these units. 
> > 
> >     > 
>     I had the PSU fail in my 58503A. It keeps trying to start, then stops. I have checked capacitors with an ESR meter, but could not fix it. 
> 
>     Three is a good chance your unit takes the same PSU. If so
> 
>     https://www.ebay.co.uk/itm/BEL-POWER-MAP55-4003-55W-Quad-Output-Embedded-Switch-Mode-Power-Supply-SMPS/132833037734
> 
>     may be of interest. I had an offer of £45 accepted yesterday. 
> 
>     Those power supplies can often be found up to £300 on eBay, but Arrow Electronics sells them new at £120. 
> 
> 
>     Dave. 
> 
>         > > 
> >     >