serial cable connected to the K2 by accident

[oe9fwv]

hi,

what can happen if a full serial cable from the PC is connected to the K2
serial IO port?
I have a special cable for the K2 with RX TX GND lines only, but I mixed it
up with the normal serial cable.

I have the 10W K2. CAT-control works fine - could I have done some
damage to the K2 which is not noticable now? If yes, how can I test it?

73! de Werner
OE9FWV

--  
 Thought for the day:
    Book (n): a utensil used to pass time while waiting
    for the TV repairman.



PGP-Key: <http://www.qsl.net/oe9fwv/furlan.asc>
Fone [phone]
Fax [phone]
Mobile      [phone]


_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[g4ilo-2]

What normally happens is that you blow the auxbus, and end up with a dead
radio. Since yours still works, you probably got away with it. Perhaps
there was nothing connected to that pin on your cable.

Julian, G4ILO
G4ILO's Shack: www.g4ilo.com

"Dr. Werner Furlan" wrote:

hi,

what can happen if a full serial cable from the PC is connected to the K2
serial IO port?
I have a special cable for the K2 with RX TX GND lines only, but I mixed it
up with the normal serial cable.

I have the 10W K2. CAT-control works fine - could I have done some damage
to the K2 which is not noticable now? If yes, how can I test it?


_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[Don Wilhelm-3]

Werner,

If the computer remained off during the time the serial cable was
connected, no damage would have resulted, but if the computer was turned
on and the pot was active, quite a few components could potentially be
damaged.

A couple of years ago, Tom Hammond (N0SS) published a list on the
reflector of the potential components that could be damaged, and that
list may still be available in the archives.  In the worst case,
anything connected to the AUXBUS, VRFDET, 8R and 12CTRL signal lines in
the K2 are at risk.

If your K2 still works, there is a chance that no damage occurred.

73,
Don W3FPR

Dr. Werner Furlan wrote:

> hi,
>
> what can happen if a full serial cable from the PC is connected to the K2
> serial IO port?
> I have a special cable for the K2 with RX TX GND lines only, but I mixed it
> up with the normal serial cable.
>
> I have the 10W K2. CAT-control works fine - could I have done some
> damage to the K2 which is not noticable now? If yes, how can I test it?
>
> 73! de Werner
> OE9FWV
>
> --  
>  Thought for the day:
>     Book (n): a utensil used to pass time while waiting
>     for the TV repairman.
>
>
>
> PGP-Key: <http://www.qsl.net/oe9fwv/furlan.asc>
> Fone [phone]
> Fax [phone]
> Mobile      [phone]
>
>
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
>  http://mailman.qth.net/mailman/listinfo/elecraft   
>
> Help: http://mailman.qth.net/subscribers.htm
> Elecraft web page: http://www.elecraft.com
>

_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[David Woolley (E.L)]

[hidden email] wrote:
> What normally happens is that you blow the auxbus, and end up with a dead
> radio. Since yours still works, you probably got away with it. Perhaps
> there was nothing connected to that pin on your cable.

That sounds like an accident waiting to happen!

Ideally Elecraft wouldn't have used a 9 pin D connector, but, as they
have, I think I may isolate that pin initially, maybe by not installing L1.

Some other thoughts were:

- connectorising the signal on the jumper cable;
- connectorising L1;
- inserting a back to back plug and socket into the D connector
   to isolate the non-standards lines.

It sounds like the other risky signal is the 12V one, but I think the
worst that happens is that the filter choke acts as a fuse.  It also
isn't at risk with normal RS232C signals, only with the ground
connection.  Is it worth trying to add a PCB mounting fuse?  Would the
voltage drop be too large?

_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[oe9fwv]

hi David,

On 30 May 2007 at 22:27, David Woolley wrote:

> > What normally happens is that you blow the auxbus, and end up with a
> > dead radio. Since yours still works, you probably got away with it.
> > Perhaps there was nothing connected to that pin on your cable.
>
> That sounds like an accident waiting to happen!

>From Don I got the advice to key the female DB9 connector at Pin 4 - not
used on the K2. (I put a short piece of thin plastic into the hole and fixed it
with super glue)
That's what I did. I had to remove Pin 4 on the male DB9 serial cable with
only Pin 2,3 and 5 wired.

By the way, tonight the serial com2 on my PC died - that's worse because
there is no chance to repair the mainboard. (this was just coincidental, I did
not connect anything wrong to this comport.)

73! de Werner
OE9FWV




--  
 Money isn't the root of all evil.  LACK of money is.



PGP-Key: <http://www.qsl.net/oe9fwv/furlan.asc>
Fone [phone]
Fax [phone]
Mobile      [phone]


_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[Guido Tedeschi-2]

You can also build this simple optocoupled interface:
http://www.hamlan.org/tech/k2optocat/k2optocat.htm
Ciao and 73
Guido, ik2bcp


2007/5/31, Dr. Werner Furlan <[hidden email]>:

> hi David,
>
> On 30 May 2007 at 22:27, David Woolley wrote:
>
> > > What normally happens is that you blow the auxbus, and end up with a
> > > dead radio. Since yours still works, you probably got away with it.
> > > Perhaps there was nothing connected to that pin on your cable.
> >
> > That sounds like an accident waiting to happen!
>
> >From Don I got the advice to key the female DB9 connector at Pin 4 - not
> used on the K2. (I put a short piece of thin plastic into the hole and fixed it
> with super glue)
> That's what I did. I had to remove Pin 4 on the male DB9 serial cable with
> only Pin 2,3 and 5 wired.
>
> By the way, tonight the serial com2 on my PC died - that's worse because
> there is no chance to repair the mainboard. (this was just coincidental, I did
> not connect anything wrong to this comport.)
>
> 73! de Werner
> OE9FWV
>
>
>
>
> --
>  Money isn't the root of all evil.  LACK of money is.
>
>
>
> PGP-Key: <http://www.qsl.net/oe9fwv/furlan.asc>
> Fone [phone]
> Fax [phone]
> Mobile      [phone]
>
>
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
>  http://mailman.qth.net/mailman/listinfo/elecraft
>
> Help: http://mailman.qth.net/subscribers.htm
> Elecraft web page: http://www.elecraft.com
>

_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[David Woolley (E.L)]

Guido Tedeschi wrote:
> <div class="moz-text-flowed" style="font-family: -moz-fixed">You can
> also build this simple optocoupled interface:
> http://www.hamlan.org/tech/k2optocat/k2optocat.htm

That might have a use in relation to the KAP100, but it doesn't address
the current problem, and doesn't make sense for the KIO2.

It doesn't solve the problem because it protects Auxbus by by simply not
connecting it to the cable on the outside of the KA2, leaving the signal
vulnerable to the insertion of an incorrect cable into the connector on
the KA2 itself.

It doesn't make sense for the KIO2, because the purpose of that is to
generate bipolar voltages and level shift to them, the former being done
to ensure that the full RS232 specification is met, rather than the weak
compatibility achieved by stealing power from the fully conforming
equipment on the other end of the cable.  This interfaces steals power
for the actual RS232 drivers, and in a way that basically treats the
RS232 inputs as current loop operated, rather than bipolar voltage driven.

In my view, if one wanted to opto-isolate the RS232 signals, the right
way of doing this is to interface on the control board connector, and
completely replace the KIO2.

--
David Woolley
Emails are not formal business letters, whatever businesses may want.
RFC1855 says there should be an address here, but, in a world of spam,
that is no longer good advice, as archive address hiding may not work.
_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com