[Elecraft] KIO3B repair

[Clark Macaulay WU4B]

I’ve been reading the mail on this topic.  I purchased a KIO3B from the
last run thinking it would be a good backup when the KIO3A failed.  I
prefer using RS232 for my K3 and K2 rig control using a PCI card in the
shack computer.  Digital modes are of slight interest using a sound card in
the shack computer.

Looks like I’ll keep the KIO3B in the box and may never need it.  Like Bob,
and others I suspect, at my stage of life 82 years young, my K3 s/n 6011,
will be probably be my last HF rig.  It’s been a great run with the gear
(K1, K2, K3) from Watsonville.  Thanks for the memories!

Clark / WU4B



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On Sun, May 11, 2025 at 11:57 AM Joe Subich, W4TV <lists at subich.com> wrote:

>
>
> > A caveat, I have not tested the 'repaired' KIO3B board, that's still
> > on my to-do list. Hopefully D1/R27 did their jobs and sacrificed
> > themselves for the good of the board.
> D1 should do its job.  However, R27 is between the USB cable shield
> and circuit common ("ground") which indicates your original failure
> was a reverse voltage condition (shield became positive relative to
> Vbus).
>
> This does point out the real problem with Elecraft and repair of the
> KIO3B ... Elecraft have a ~$400 minimum service fee (@ $100/hr).  A
> "simple" repair/replacement of D1/R27 would be more expensive at the
> minimum service fee than the replacement KIO3b (when they were
> available).  Now, the time to troubleshoot a bad KIO3b might consume
> the entire 4 hour minimum if the damage was extensive - although
> given my experience with USB products the mast majority of the
> problems are likely to be D1 with or without R27 (particularly since
> Elecraft seem to have gone to great lengths to isolate the "USB Core"
> from "raw" Vusb.
>
> 73,
>
>     ... Joe, W4TV
>
>
> On 2025-05-11 10:40 AM, John Canfield wrote:
> > My KIO3B suffered the typical USB failure a few years ago but
> > fortunately Elecraft was still repairing the K3s then. They replaced the
> > KIO3B board and returned the old one. I kept the old board for a long
> > time but got interested in trying to repair the failed board (USB
> > defective but RS-232 was fine.)
> >
> > My USB failure (or I suppose the most obvious one) is on the Digital I/O
> > Module (E850646) board. Specifically D1 and R27. D1 is an STMicro
> > USBLC6-2P6, an ESD protection device. Mouser part # 511-USBLC6-2P6. R27
> > is just a zero ohm resistor, I suppose it's used as a fuse. If it's not
> > obvious these are surface mount devices so it does take a bit of
> > patience and of course the right tools to replace them (or any surface
> > mount device for that matter.)
> >
> > An intact D1 will have an all black case/housing/shell (whatever you
> > want to call it), the defective one on my board literally had the top
> > part of the case/shell blown off. R27 is in series with the shield lead
> > from the USB connector to ground, my R27 was open. D1 and R27 are
> > located very near the USB connector so they are fairly easy to find. D1
> > was inexpensive, I forgot how much but I bought five of them just in
> case.
> >
> > A caveat, I have not tested the 'repaired' KIO3B board, that's still on
> > my to-do list. Hopefully D1/R27 did their jobs and sacrificed themselves
> > for the good of the board.
> >
> > 73 John W5TWO (ex WB5THT)
> > In the Texas Hill Country
> >
>
>
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