[Elecraft] KIO3B Main Board Repair

[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

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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:
   dubususa at gmail.com