[time-nuts] Errors on HP 58503A GPS time & frequency reference receiver b...

EWKehren at aol.com EWKehren at aol.com
Thu Dec 11 16:52:25 EST 2014

who did you buy it from?
In a message dated 12/11/2014 4:47:02 P.M. Eastern Standard Time,  
drkirkby at kirkbymicrowave.co.uk writes:

On 11  December 2014 at 01:10, Bob Camp <kb8tq at n1k.org> wrote:
>  Hi
> I suspect that if you look closely at the board in the  unit, it’s got 
water stains on it ….
> Bob

I suspect you  might be right Bob, but I am not going to break the seal
to open it up to  find out. I will be contacting the seller, to see
what they  offer.

Does anyone have any experience with these having the voltages  going
unstable? These two log entries show the 15 V is going both too  high
and too low.

Log 004:20141017.00:00:11:  15V is out of  tolerance, value: 16.62
Log 007:20141017.00:00:11:  15V is out of  tolerance, value: 13.78

This shows the 5V rail has gone too  high

Log 078:20141210.00:00:11:  5V is out of tolerance, value:  5.54

This shows the oven current is out of spec - whether it is too  high or
too low is anyones guess

Log 022:20141205.04:42:26:   Primary oven current is out of tolerance,
value: 115.81

I'm guessing  the 115.81 is mA, but I don't know. If it is mA, 116 mA
doesn't seem an  unreasonable number. I assume this will have an
oscillator "similar" to a  10811A - lets not worry about the exact
type. According to the data sheet  for the 10811A, the oven resistance
has a minimum of 42 Ohms. Supply  voltage is 20-30 V. So a quick
calculation shows the turn-on current could  be as high as 30/42 =  714
mA, so 116 mA doesn't sound unreasonable.  The 10811A data sheet says
the power consumption is typically 2 W steady  state at 20 V. So that's
a current of 0.1 A @ 20 V, so once again, 116 mA  seems quite normal
for a steady state value, and a bit low for heating  up.

I've not opened a case on eBay yet. I will do at some point, but  would
like to know the likely fault on this. The fact it does actually  work,
probably indicates there's nothing too serious wrong with it.  I
suspect a cap(s) is failing, which is quite common with age,  and
fairly easy to fix.

Having looked carefully, there are a few  tell-tale signs this case is
actually not an original HP one, but I am not  overly bothered by that.
It looks good, and if the unit worked, I would be  happy.

It is rather annoying that people leave this seller positive  feedback,
or no feedback if they get their complaints resolved. I've had a  few
people email me about this seller, but they all seem keen not to  say
anything on a list, and looking at the feedback of the seller, it  is
still 100% positive. There is definitely something fishy about  this
seller, but the 100% positive feedback does not reflect that.

I  also wonder why they cleared the log, as the first log entry shows
Log  001:20141017.00:00:00:  Log cleared

I wonder if they had problems  that they thought they had  solved?

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