RS 232 problem

[Van W1WCG]

I believe someone sent me email today regarding a problem I had with failure of the RS232 in my KPA100 some time ago.  I inadvertently deleted the email before getting a return address or name.

For that person:
The problem I had turned out to be three of the tiny RF chokes plus the MAX chip were destroyed.  I have no idea what happened -- the K2 had been connected to my computer through the RS232 cable for some time, and was use only intermittently.  There came a time when I tried to use software control of the K2, only to find that it no longer worked.  I must assume that there was some transient (perhaps a nearby lightning strike???) that caused enough voltage difference in the cable to do that kind of damage.  Nothing was burnt that could be seen, but the voltages on the MAX1406 were clearly not what they should have been, and ultimately the chokes in both the TX and RX lines were found to be open.  Hope this helps!
If it doesn't answer your question, please return the email....

73, Van W1WCG
K2 #2634/5510
KX1 #306
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[Stuart Rohre]

Frank,
You left out an important piece of information.  Was the K2 plugged into an
antenna at the same time you had it on the computer and lost the MAX chip
and the components?

RS232 used to cause a lot of modem failures, because those chips make a
great fuse for lightning surges that would come down the phone lines, if the
modem was left connected during a storm!   That is the most likely cause of
the demise you had.

Even without RS 232 or other Computer interfaces to a rig, hams should
unplug their antennas from the rigs when not on the air!

Stuart
K5KVH


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[Van W1WCG]

Stuart, K5KVH, reminds me that I left out an important point concerning my
RS 232 problem -- i.e. was it connected to an antenna as well as the
computer
when the failure occurred?

Yes, it was connectied to an antenna, Stuart -- the antenna is a Butternet
vertical on the roof with a couple
of long radials.  Certainly a target for lightning nearby!  I've never (to
my knowledge)
had a direct hit, but I know that nearby strikes can induce high voltages
and currents
in any nearby conductor.

73,
Van W1WCG

> Frank,
> You left out an important piece of information.  Was the K2 plugged into
> an antenna at the same time you had it on the computer and lost the MAX
> chip and the components?
>
> RS232 used to cause a lot of modem failures, because those chips make a
> great fuse for lightning surges that would come down the phone lines, if
> the modem was left connected during a storm!   That is the most likely
> cause of the demise you had.
>
> Even without RS 232 or other Computer interfaces to a rig, hams should
> unplug their antennas from the rigs when not on the air!
>
> Stuart
> K5KVH

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