[time-nuts] HP 58501A reference clocks

Bob Camp kb8tq at n1k.org
Sat Mar 26 21:35:00 EDT 2016


Hi

I wold not be at all surprised if it has a previous location surveyed into it’s little 
brain. As long as it still thinks it’s in Virginia (or wherever) it’s not going to 
lock up in it’s new home. 

Depending where it came from, it might be a lab unit for initial design checkout.
If HP shipped a unit like that to a customer, it would be the first example I’ve seen. 
Since there are a *lot* of things I have not seen … that may not mean much. 

Bob

> On Mar 26, 2016, at 7:13 PM, Steve D <kls at ve7fm.com> wrote:
> 
> Hi group,
> 
> I recently purchased an HP 58XXXA or 58501A precision reference clock unit.
> The unit is clearly a prototype made by HP for Ericsson GE. The front label
> actually says 58XXXA. The serial number of the unit is EGE001P. It has a
> GPS antenna in and 10 MHz, 19.2 MHz, 9600 kHz and a 600/300/100 Hz outputs.
> Inside is has a main board with part # 58501-60001, a 10 MHz OCXO part #
> 05071-60219, a Motorola GPS part # 84D43215M02, a hand built board which
> generates (likely phase locked) 19.2 MHz from the 10 MHz, a hand built
> board to hold the three front mounted LED's and a third party power supply.
> 
> At power up the front panel power LED comes on and a second later the GPS
> and ALARM LED's toggle on/off in sequence. The main board LED's also all
> toggle and then one of them flashes once per second. I can communicate with
> the unit via SCPI using 9600/8/N/1 RS232 data.  I was able to verify the
> GPS does receive a signal as the time is correct and the date updates but
> is 1024 weeks behind(GPS rollover bug). However the "GPS LOCK" and "ALARM"
> LED's never do anything. The 10 MHz out the back does travel between
> 9,999,997 and 10,000,003 Hz which follows the EFC test point voltage that
> goes between -5 and +5 volts. I have found very few SCPI commands that
> work. At this point they are:
> 
> *IDN? which gives: HEWLETT-PACKARD,58501A,0,Fiji_EGE
> *CLS
> *TST? which gives 1 (possibly indicating a rom error)
> PTIME:DATE?
> PTIME:TIME?
> SYSTEM:ERROR?
> 
> I have pulled the four firmware roms and reseated them as well as the
> Xilinx chip, it made no difference. So the question is, did it ever work or
> has something failed?
> 
> I find it to be a fascinating piece of equipment and think the hand built
> boards are super cool to see, but lets face it, it would be more fun if it
> worked.
> 
> I have posted pictures and a firmware dump on the eevblog forum here:
> http://www.eevblog.com/forum/testgear/prototype-hpagilent-gps-based-refererence-clocks-generator/
> 
> I'm coming to this group to see if anyone has any ideas or knowledge of the
> unit.
> 
> thank you!
> 
> Steve VE7FM
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