[time-nuts] Oncore VP problem

GandalfG8 at aol.com GandalfG8 at aol.com
Wed Jul 18 19:24:06 EDT 2007

In a message dated 18/07/2007 21:25:35 GMT Daylight Time,  
jason at extremeoverclocking.com writes:

I  wouldn't worry too much about not having TRAIM. As long as your GPS has  a
good view of the sky you should be alright. If you really need a  higher-end
receiver then there's the newer M12M-T.

Do you have any  pictures of the adapter board / product? I'm curious to see
what it looks  like.

Hi Jason
I don't really need anything any better right now, just being  greedy:-)
Although it would have been nice to have the extra timing options  I'm just 
pleased to find I have the PPS output after all.
With most of my test gear in storage right now, including Z3801A and  other 
references, I was looking for a quick way to check out a Parthus GPS  standard 
that hasn't been behaving quite as I expected.
The QEX project from last year seemed to offer an ideal  solution, without 
the output dividers/drivers it's just one PIC, one op  amp, and a level 
if you don't count the GPS receiver and an HP 10811 that is:-)
The unit I'm using was marketed around 1996 by Maplin Electronics in the UK  
as their "GPS Development System".
I bought this one recently from a company who had it as left over  NOS, they 
used them in 1997 as accurate timing sources for lighting/effects  in a theme 
Maplin are quite a large retail chain in the UK, similar to RadioShack  but 
without the radios:-),  and they also published a magazine at  the time.
I think this may have started as a magazine project that they decided to  
market as a finished product.
Basically, it's just an Oncore on an interface board that  contains a MAX232 
IC and a 5 volt regulator.
I suspect it's very similar to the Motorola evaluation kit.
It's put together quite nicely in a small extruded case but  doesn't seem to 
be very well designed.
To start with, they rate the supply from 8 to 16 volts with a 16 volt  
electrolytic across it.
Probably ok, but I prefer a margin so changed it.
The electrolytic across the negative 8.5 volt output from the MAX232 was  the 
wrong way round, I thought it was a one off until I found the PCB marked up  
that way.
And finally, as I mentioned earlier, the front panel screening is  wrong.
Other than that, it seems ok:-)
I've got a photo of the outside but that doesn't tell you much  so I'll take 
some pictures of the PCB etc and let you have those  later.
I'll also try to provide a copy of the interface schematic.


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