KIO3B Main Board Repair

[Mike K4PI]

I have ended up with 2 bad KI03B boards E850645.  Both bad in the USB
circuit.  I did some basic checks resistance wise they recommended but
found no problems.  Elecraft said chances of repair was slim and would
not be economical to try.  I think all the other functions are okay ie
think they are still working okay if you come in via the serial port. 
Seems a shame to toss them into the dumpster  but unless someone has had
some experience of repairing them that may be the route.  Anyone ever
attempted at repair of the USB circuit on these?  73 Mike K4PI


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[Greg Beat]

Mike -

You can view the Schematic diagrams (6 pages) for the Elecraft KIO3B module.
https://ftp.elecraft.com/K3S/Manuals%20Downloads/E740323%20K3s%20Schematic%20Files.pdf
The KIO3B is a multi-function module, that includes these functions:
1. RF Board interface
2. Digital I/O interface
3. Audio I/O interface
4. USB, Codec, RS232
FTDI FT232R (USB), TI PCM2901 (CODEC), TUSB2036 (2/3 port USB hub)
5. Digital I/O
6. Audio I/O
==
It is NOT impossible to repair or troubleshoot (component-level),
BUT it can be time consuming for the novice or weekend technician.
This is why Elecraft stated “economical” (their bench time is NOT Free).
—
Sage advice from my high school electronics instructor, WB9FUR (sk, 2016) has served me well : External event (ESD, Over-voltage, Op error) and I/O ports are major causes of module or circuit failures.  Electronic devices rarely “die” for no reason (assumes QA production of part).
—
“What functionality” has failed will narrow the circuit areas and components to examine.  IF you can “think thru” those observed symptoms, many failures can be pinpointed with a DVM to a few key components.
SMT repair experience and tools reduces repair time.
—
This summer, I repaired an ESE ES-188 Master Clock ... that the reseller suspected was not working properly.  Visual and operations inspection:
* Not damage to tinned copper foil traces on PC board.
* Bulging 25V electrolytic caps (85° import brand) on DC filtering - replaced (105°)
* Multi-serial TTL level ports from microprocessor were inconsistent
- replaced MAX233 (resolved one port)
- replaced 74LS04 and 74LS08 (resolved other ports)

I did not even pull out my DVM ... the secondary DC ripple was eliminated, and an external event (ESD?) likely entered thru serial port ... damaged the 3 ICs replaced.
Those 3 parts were closest to DC power bus and serial port entrance to PC board.

It’s been running on the bench, driving NTP and IRIG-B remote clock for past 3 months ... no issues.  IF I were to resell, I would check with DVM & possibly scope.

greg, w9gb
===
Date: Thu, 29 Oct 2020 17:43:44 -0400
From: K4PI <[hidden email]>
To: Elecraft Mail Reflector
Subject: [Elecraft] KIO3B Main Board Repair

I have ended up with 2 bad KI03B boards E850645.
Both bad in the USB circuit.
I did some basic checks resistance wise they recommended, but found no problems.
Elecraft said chances of repair was slim and would not be economical to try.
I think all the other functions are okay (think they are still working okay if you come in via the serial port).
Seems a shame to toss them into the dumpster, but unless someone has had
some experience of repairing them that may be the route.
Anyone ever attempted at repair of the USB circuit on these??

73 Mike K4PI
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[Edward R Cole]

In my case the RS232 I/F in my K3 (SN-4340) quit communicating with
WSJT-X.  Tested with K3 Utility with same result.  Tried a different
USB/RS232 cable, still not communicating.  Troubleshot 9-pin
receptacle and discovered the ground pin was not grounded.  Pulled
out the KIO3A and found the chip inductor on the ground line had
blown up open ckt.  Removed it and substituted a wire jumper (still
not working).

At that point I was going to have to rig up a test cable to be able
to troubleshoot the module unplugged from the K3.  Instead I sent it
to Elecraft Repair.  They had it for 28-days and then replied that a
new digital board was needed as the existing board was not
reparable.  They are on order.

I did have the option to buy a KIO3B but that was over $400 before
shipping (and also not in stock)  I don't need or use the USB port.

I worked 1966-2009: ten years as an RF engineer, and the rest as
technician doing SM level troubleshooting/repairs.  After retiring I
had a small business building transverters and amplifiers from kits
(all SM).  I have a pretty decent workbench and test equipment to
26-GHz.  II could have spent the effort in building a test jig and
trying to troubleshoot on my own.  I figured it easier to let the
experienced staff at Elecraft do it.

Hoping to get my KIO3A repaired when board order arrives.  I've
decided to set up my KX3 for computer modes using a Rig Runner NOMIC
I/F.  I'll post the project on my website when done.  The KX3 will
use WSJT-X for running JT65B on 2m-eme by driving a 2m transverter.
on 28-MHz with 3w.

73, Ed - KL7UW

-----------------------------------------------------
You can view the Schematic diagrams (6 pages) for the Elecraft KIO3B module.
https://ftp.elecraft.com/K3S/Manuals%20Downloads/E740323%20K3s%20Schematic%20Files.pdf
The KIO3B is a multi-function module, that includes these functions:
1. RF Board interface
2. Digital I/O interface
3. Audio I/O interface
4. USB, Codec, RS232
FTDI FT232R (USB), TI PCM2901 (CODEC), TUSB2036 (2/3 port USB hub)
5. Digital I/O
6. Audio I/O
==
It is NOT impossible to repair or troubleshoot (component-level),
BUT it can be time consuming for the novice or weekend technician.
This is why Elecraft stated ?economical? (their bench time is NOT Free).
?
Sage advice from my high school electronics instructor, WB9FUR (sk,
2016) has served me well : External event (ESD, Over-voltage, Op
error) and I/O ports are major causes of module or circuit
failures.  Electronic devices rarely ?die? for no reason (assumes QA
production of part).
?
?What functionality? has failed will narrow the circuit areas and
components to examine.  IF you can ?think thru? those observed
symptoms, many failures can be pinpointed with a DVM to a few key components.
SMT repair experience and tools reduces repair time
<left off the rest of the reply>

73, Ed - KL7UW
   http://www.kl7uw.com
Dubus-NA Business mail:
   [hidden email]

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[Edward R Cole]

Received e-mail from Elecraft that my KIO3 board is being
shipped.  Cost of new digital board $187.50 + $17.50 shipping.

So my K3 will be restored for operating JT65 on eme end of the
month.  Only my 2m-eme array and tower crashed two days ago in high winds.
http://www.kl7uw.com/2m-eme_down_1.jpg

BTW I got my KX3 running on digital modes by use of a Rigblaster
NOMIC.  I'll have a webpage up in a couple days with a description.
http://www.kl7uw.com/techtopics.htm

Anyone want to borrow Murphy for a few months!

73, Ed - KL7UW
   http://www.kl7uw.com
Dubus-NA Business mail:
   [hidden email]

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