K3 - KIO3 RS-232


kg9hfrank@gmail.com
 

PSA for the KIO3 board

After fixing several KIO3 boards (RS-232) I found there was a common thread in all that failed.
Every ham had bundled the RS-232 cable with the coax cable or (and?) the DC cables to keep them neat.

Keep in mind that if a transient comes down your coax or other lines, it can be easily coupled into the RS-232 cable if bundled with them.

While I do not have a large tower, I did have a direct hit to a tree that supports my 80 meter loop.  Fortunately two Polyphasers did their job.  I try to keep like cables bundled with like, but I dont tie them to anything before the AC or Polyphaser protector.   My Elecraft cable does not touch any other cables, and goes straight to the laptop.  I also grounded the laptop and used a surge protector on the charger cable which is plugged into the A/C all the time.

de KG9H


john ni0k
 

Motorola's R56 manual addresses this directly. It specifies the spacing between different types of cables.

Induced current surges can cause this type of failure. You may install surge protection on the wires connected to the K3. It is vitally important to bond EVERYTHING in your shack to a common ground. Many forget the computer in the shack... that must be bonded as well. If you have a laptop the only ground point is the locking screw for the VGA connector.

YMMV


--
73,
-de "Curly" John NI0K in rural Debs, MN USA
Hamshack Hotline: 6100000271

kg9hfrank@... via groups.io wrote on 9/7/2022 9:15 AM:

PSA for the KIO3 board

After fixing several KIO3 boards (RS-232) I found there was a common thread in all that failed.
Every ham had bundled the RS-232 cable with the coax cable or (and?) the DC cables to keep them neat.

Keep in mind that if a transient comes down your coax or other lines, it can be easily coupled into the RS-232 cable if bundled with them.

While I do not have a large tower, I did have a direct hit to a tree that supports my 80 meter loop.  Fortunately two Polyphasers did their job.  I try to keep like cables bundled with like, but I dont tie them to anything before the AC or Polyphaser protector.   My Elecraft cable does not touch any other cables, and goes straight to the laptop.  I also grounded the laptop and used a surge protector on the charger cable which is plugged into the A/C all the time.

de KG9H


Kent Trimble, K9ZTV
 

Assuming your laptop has a VGA connector with a locking screw, which none of mine have.

K9ZTV


On 9/7/2022 9:38 AM, john ni0k wrote:
If you have a laptop the only ground point is the locking screw for the VGA connector.



Virus-free.www.avg.com


Mike - K8CN
 

Is it the case that a VGA connector body (metal shell)
would be bonded to the laptop motherboard ground plane (DC return)?
I've never thought to make such a measurement.

Mike, K8CN

From: Elecraft-K3@groups.io <Elecraft-K3@groups.io> on behalf of Kent Trimble, K9ZTV <k9ztv@...>
Sent: Wednesday, September 7, 2022 11:15 AM
To: Elecraft-K3@groups.io <Elecraft-K3@groups.io>
Subject: Re: [Elecraft-K3] K3 - KIO3 RS-232
 

CAUTION: This email originated from outside of the University System. Do not click links or open attachments unless you recognize the sender and know the content is safe.

Assuming your laptop has a VGA connector with a locking screw, which none of mine have.

K9ZTV


On 9/7/2022 9:38 AM, john ni0k wrote:
If you have a laptop the only ground point is the locking screw for the VGA connector.



Virus-free.www.avg.com


kg9hfrank@gmail.com
 

NI0K, thanks for your information, if you have the link for R56,  it would be a huge addition to this post!  Most dont have access to that doc.

Mike, K8CN, I agree most laptops dont have one, you may have to get creative.  Remember the laptop ground is an addition, the source if you will, into the KIO3 is the RS-232 cable.
Protect that first!


john ni0k
 

R56 link:

68P81089E50.book - Motorola_R56.pdf


--
73,
-de "Curly" John NI0K in rural Debs, MN USA
Hamshack Hotline: 6100000271

kg9hfrank@... via groups.io wrote on 9/7/2022 10:25 AM:

NI0K, thanks for your information, if you have the link for R56,  it would be a huge addition to this post!  Most dont have access to that doc.

Mike, K8CN, I agree most laptops dont have one, you may have to get creative.  Remember the laptop ground is an addition, the source if you will, into the KIO3 is the RS-232 cable.
Protect that first!


David Cutter
 

Are the USB connectors floating?  If not, there are usually 2 or more of these on a laptop and one could be dedicated to this task.   Perhaps we should save those old laptops that have better grounding opportunities, eg Lenovo et al.  

David G3UNA


On 07/09/2022 16:25 kg9hfrank@... <kg9hfrank@...> wrote:


NI0K, thanks for your information, if you have the link for R56,  it would be a huge addition to this post!  Most dont have access to that doc.

Mike, K8CN, I agree most laptops dont have one, you may have to get creative.  Remember the laptop ground is an addition, the source if you will, into the KIO3 is the RS-232 cable.
Protect that first!


john ni0k
 

R56 Section 9.9.1.5, page 9-12:
Cable Separation and Grouping Within Racks and Cabinets:
Cabling within racks and cabinets shall be grouped according to function. Garoups are defined as follows:
  • AC power cords
  • DC power cables
  • Ground conductors
  • RF transmission cabling'
  • Data, control, signal and timing reference cabling and telephone cabling

Cable groups within racks and cabinets shall be separated by 2" from other cable groups.

When practical cable groups at or in close proximity to equipment chassis should be separated by 2" or cross at 90 degree angle.


Cable Separation and Grouping within Cable Trays

    • Cable groups shall be separated a minimum of 2" from other cable groups.
    • Transmission lines for transmitting stations shall be separated a minimum of 4" from electrical lights, power and signaling circuits
    • Groups are defined as:
      • AC power, DC power, ground conductor and RF transmission cabling
      • Data, Control, signal and timing reference cabling
      • Telephone cabling

--

-J
kg9hfrank@... via groups.io wrote on 9/7/2022 10:25 AM:

NI0K, thanks for your information, if you have the link for R56,  it would be a huge addition to this post!  Most dont have access to that doc.

Mike, K8CN, I agree most laptops dont have one, you may have to get creative.  Remember the laptop ground is an addition, the source if you will, into the KIO3 is the RS-232 cable.
Protect that first!


KE1F Lou
 

My 3 station monitors have no singular ground post to connect to my station ground.

Lou KE1F

On 9/7/2022 15:25, kg9hfrank@... wrote:

NI0K, thanks for your information, if you have the link for R56,  it would be a huge addition to this post!  Most dont have access to that doc.

Mike, K8CN, I agree most laptops dont have one, you may have to get creative.  Remember the laptop ground is an addition, the source if you will, into the KIO3 is the RS-232 cable.
Protect that first!


Jim Brown
 

On 9/7/2022 8:21 AM, Carter, Michael wrote:
Is it the case that a VGA connector body (metal shell)
The shells of D-connectors and USB connectors are required to be chassis ground. In the KIO3, audio I/O have a capacitor between sleeve and chassis, and W4TV has noted that there are small inductors as load or resistors that blow with a strike. There are also 600 ohm resistors as build-out and load in audio I/O, which hasn't been done in pro audio for more than 50 years. It's bad design on the board.

Most destructive failures would be prevented by proper grounding and bonding, but many hams have no clue about that. There's an excellent ARRL book by N0AX, to which I contributed, and a slide deck on my website for a talk I've done for west coast ham conventions and to several clubs. k9yc.com/publish.htm

73, Jim K9YC


kg9hfrank@gmail.com
 

Jim
Of course I figured I would hear from you
Saw your presentation at Shure many years ago
I’m the one that runs the EMC MiniSymposium here in Chicago lol




Sincerely,  Frank Krozel t: 1-630-924-1600 frank@...
BSEE,   AASEET,   FCC Lic.# PG-18-19178,   KG9H
Electronic Instrument Associates - Central, Inc. ...since 1971


On Sep 7, 2022, at 1:38 PM, Jim Brown <k9yc@...> wrote:

On 9/7/2022 8:21 AM, Carter, Michael wrote:
Is it the case that a VGA connector body (metal shell)

The shells of D-connectors and USB connectors are required to be chassis ground. In the KIO3, audio I/O have a capacitor between sleeve and chassis, and W4TV has noted that there are small inductors as load or resistors that blow with a strike. There are also 600 ohm resistors as build-out and load in audio I/O, which hasn't been done in pro audio for more than 50 years. It's bad design on the board.

Most destructive failures would be prevented by proper grounding and bonding, but many hams have no clue about that. There's an excellent ARRL book by N0AX, to which I contributed, and a slide deck on my website for a talk I've done for west coast ham conventions and to several clubs.  k9yc.com/publish.htm

73, Jim K9YC








Jim Brown
 

Hi Frank,

Yes, I remember those mini-symposiums well -- very useful sessions, some elements of which I have quoted often.

73, Jim

On 9/7/2022 11:59 AM, kg9hfrank@... wrote:
Jim
Of course I figured I would hear from you
Saw your presentation at Shure many years ago
I’m the one that runs the EMC MiniSymposium here in Chicago lol
Sincerely,  Frank Krozel t:1-630-924-1600 <tel:1-630-924-1600>frank@... <mailto:frank@...>
BSEE,   AASEET,   FCC Lic.# PG-18-19178,   KG9H
Electronic Instrument Associates - Central, Inc. ...since 1971
w: www.electronicinstrument.com <http://www.electronicinstrument.com/>  d/l our linecard athttp://www.electronicinstrument.com/lc.pdf <http://www.electronicinstrument.com/lc.pdf>

On Sep 7, 2022, at 1:38 PM, Jim Brown <k9yc@...> wrote:

On 9/7/2022 8:21 AM, Carter, Michael wrote:
Is it the case that a VGA connector body (metal shell)
The shells of D-connectors and USB connectors are required to be chassis ground. In the KIO3, audio I/O have a capacitor between sleeve and chassis, and W4TV has noted that there are small inductors as load or resistors that blow with a strike. There are also 600 ohm resistors as build-out and load in audio I/O, which hasn't been done in pro audio for more than 50 years. It's bad design on the board.

Most destructive failures would be prevented by proper grounding and bonding, but many hams have no clue about that. There's an excellent ARRL book by N0AX, to which I contributed, and a slide deck on my website for a talk I've done for west coast ham conventions and to several clubs.  k9yc.com/publish.htm

73, Jim K9YC