Bob;
Thanks a bunch for your information. I am sure this 5K does not have
the V2.0 upgrade. There is one other piece of information of
interest. In the last two outages other commercial equipment also
had programming problems. I have to wonder if the 5K is susceptible
to low voltage. The dropping of a single phase in the transmission
line often will give a low voltage like 80V instead of 120V. The
Astron does not have a low voltage cut out so I could see the output
voltage dropping from 13.5 to say 6 to 8 volts under load. Could
this cause a corruption of memory in spite of the lithium battery?
I have another 5K here so I can do some testing. I will check the
jumpers as you mentioned.
Gran K6RIF
At 06:11 PM 12/8/2007, you wrote:
Hi Gran,
>On Superstition mountain in the Imperial Valley we have a S-COM 5K
that has taken repeated dumps after power line failures. The
controller is running off an Astron 35A supply. By dump I mean the
only problem is that the controller has to be re-programmed after the
AC power line failure. Now I know there are other ways than than the
13.5V for a glitch to get into the controller but I would suggest
power to be the most likely. The battery to hold up the memory has
been replaced.
The 5K has a 15V Tranzorb across the 12V power input to absorb that
kind of spike. Even without it, the power input feeds a 10V
regulator which feeds a 5V regulator, and there's lots of bulk
capacitance on both. No spike should be making it into the logic
innards. Try powering it from a different source and cycle the power
to see if memory is maintained. My guess is you'll continue to see
the same problem.
I'm suspicious about the memory backup even though the battery was
replaced. Could it be that this unit has a DS1643 in the RAM socket?
Many 5K owners did the V2.0 upgrade (which involved swapping the
coin cell and supervisor IC with a DS1643 RAM/battery/clock module)
and left the old coin cell on the board. If so, replacing the coin
cell won't do anything.
If the 5K still has the older discrete RAM/battery arrangement,
there's a push-on jumper to interrupt the memory power that should
have been pulled to replace the cell. Was it put back in?
If the 5K has the V2.0 mod, IC-9 is gone and there are two
horseshoe-shaped wire jumpers in its socket. Be sure they're making
good contact (they were soldered if we did the mod).
The COR, CTCSS, PTT and audio circuits are pretty well buffered with
respect to the outside world and I would agree that they're not
likely the problem.
73,
Bob
Bob Schmid, WA9FBO, Member
S-COM, LLC
PO Box 1546
LaPorte CO 80535-1546
970-416-6505 voice
970-419-3222 fax
www.scomcontrollers.com
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