Star Tech Journal

..
October 1992
IIANTAREX
NEW SOFTWARE
NEwPOLO
INSTALLED
MONITORS
FoRSn'J's
HIGH SPEED
BULLETIN
DIODES
BOARD SYS
Gary A. Hughes
General Coin
Portland, Oregon
James Beck
Sysop
SUBJECT
SUBJECT
Hantarex has a new line of moni-
tors out designated by the word
POLO. The distinctive thing
about them is that they are built
around a switching power sup-
ply. The switcher takes up about
~ a third of the circuit board and is
'covered by metal shielding.
S,4-TJBBS
As all of you die hard S f l J BBS
users know, the system has been
down for about a month due to an
unfortunate lightning hit. Well,
thanks to a little borrowed hard-
ware, and a lot of help from ourco-
sysop Mike Cowen, we are back
up and running.
PROBLEM
BETTER
Hantarex POLO monitors, diode
failure.
Not only are we back, we're better
than ever! The old software is out
and the newest version of OPUS
has been installed (after all a
resurection might as well include
a little enhancement).
OBSERVATION
We have seen two twenty five
inchPOLOs lately with the same
defect -a shorted D119 in the 12
volt supply. This completely
shuts the unit down as the 12v
supplies the horizontal oscillator.
1'EsT
A quick check for this is to find the
7812 regulator. Right next to that
is a boardjumperthatleads to the
switching section. This jumper is
the input to the regulator and
goes to 0v when the diode shorts.
REPLACEMENT
~The diode is a BYV28/200T. The
unit seems rather particular
about what you put in there too.
On the first one I worked on, I
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STAR*TECH Journal
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tried to use a similar size diode
out of a scan-derived voltage
source from a scrapped Hantarex
900 chassis. The POLO came up
but a wisp of smoke from the 'new'
diode warned me not to let it run
more than a few seconds.
SOLUTION
The switching supply runs many
times faster than the 15kHz hori-
zontal frequency, so even many
'fast switching' diodes are not fast
enough. The original part cured
the problem in both cases.
* * *
The new software is more "user
friendly" and a lot more powerful.
Many of the features you asked
for have been built in and the
system is a lot more expandable,
so future enhancements are eas-
ily incorporated.
ONWARD
The past is behind us, and the
future looks bright. Enhance-
ments that are going to follow
are: All old messages B.L. (Before
the Lightning) in a file for down-
loading, multiple U.S. nodes for
better access throuout the USA
and Canada not just Southeast
locations, better sysop response
(since the system behaves better
in a multi-tasking system), a
how-to section for those little
projects, an embedded systems
programming section, and an
MS-DOS programming section.
WE NEED You!
The only thing we're waiting for
is you to log back on and get
things going full speed again.