[time-nuts] Odetics 365 date/1024 week problem fix

Rob Kimberley robkimberley at btinternet.com
Mon Feb 27 11:37:50 UTC 2012

I was working for Zyfer (Odetics) when they did this mod. Yes, the only
difference between the 365 and 565 models is the GPS engine, firmware and
different front panel.

And yes, that backlight control has caught quite a few people out in the

Rob Kimberley

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Arthur Dent
Sent: 27 February 2012 00:22
To: time-nuts at febo.com
Subject: [time-nuts] Odetics 365 date/1024 week problem fix

I have owned an Odetics 365 GPStar Plus Time And Frequency System for some
time and it  works fine except for the annoying date problem that apparently
has something to do with the fairly common 1024 weeks limit where older GPS
receivers display 2012 as 1992 and the day of the year is not correct.  I
couldn't just change receivers because there appeared to be some routines in
the firmware that checked the receiver model and interpreted the data for
specific models that Odetics could have used in the late 1990s. This 365
used a Magellan 5000 OEM receiver.

I recently got a good deal on a FEI-Zyfer (Odetics) 565 that looks like the
365 and it was sold as-is because there was just a backlight but no display
and the keypad was dead. What it turned out to be was the display contrast
was turned way down and the 'beep' was turned off. The unit worked properly
but as it was received it did look dead. I bought the 'dead' 565 hoping that
maybe I could compare the two units and find a way to fix the 365 to display
the date properly.
Getting a fully operational 565 was a bonus.

What was very interesting to me was that the 365 (~1998) and the 565 (~2005)
had basically identical motherboards. The only difference I could see was
27c010 eprom and the receiver and its adaptor board. I put the 565 eprom and
receiver into the 365 and it became a 565 displaying the correct time and
date and working exactly like the 565.

The receiver in the 565 was a Motorola M12+ on a Synergy Systems adaptor
board that made the M12+ look like an older and larger Motorola UT+ board to
the 565. I tried a UT+ in place of the M12+ and it worked fine and the unit
identified it properly as a UT+ V2.2. I then duplicated the eprom and made
an adaptor board for the
UT+ board because the  Synergy Systems adaptor board for the M12+ would 
UT+ be
too difficult to copy. The adaptor board I made just has the UT+, a 7805
3-terminal 5V regulator, a back-up super cap, and a 7404 buffer (1 inverter
driving 3 in more in parallel) for the 1 PPS out. The RX and TX from the UT+
receiver are also connected so the 365 with the new eprom and receiver sees
all the proper signals and works as a 565 should. I've attached a photo of
the M12+ factory made board and the UT+ board I made so you can see what
they look like. I thought that others who have run into this same problem
might find this information helpful.


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