Serial IO/KIO2 is "deaf"

[Pieter Meiring]

I wonder id anyone can help me.

My K2 was, until a couple of months ago working fine and talking merrily to my
PC both on a terminal program and marote.
Not having used it for a couple of months I fired up the computer link
recently and found that the KIO2 was no longer talking to the computer.

I have checked:

1. the K2 sends perfectly (tested with MENU->PORT/ON>DISPLAY which displays
the frequency.

2. Tracing the RS232 signal back to the K2, it is possible to follow the data
signal from the computer through the KIO2 and into pin 3 of the Control
Board. In other words, it is not the KIO2 module that seems to be at fault as
it translates the RS232 perfectly from and to the control board; it seems the
K2 control board is not decoding the data.

All other modules (Ant tuner, DSP, SSB, 160m) still work fine.

Any ideas what to look for next please?

Pieter
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[Pieter Meiring-2]

On Saturday 28 May 2005 17:12, you wrote:

> The KIO2 translates the level from RS232 to TTL which is applied directly
> to pin 26 of the MCU thru AUX/IO connector J4/P4. Not much can go wrong
> there, but if you have a scope you can look at pin 26 and see if it is
> toggling when you send data to the K2. If not the problem is upstream, if
> it is getting to pin 26 then you may have a bad MCU, try reseating it
> before you panic and buy another one.
>
> 73 Jim, W4ATK
>
>

Thanks, Jim.
This is most bizarre!
I have a scope and have checked that the rs232 signal goes right back to pin
26 on the MCU.
I have also replaced the MCU (version 2.04P) with the previous version (2.03D)
without result.
Pieter
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[Don Wilhelm-3]

Pieter,

Check the DC levels of the signal at the MCU end with your 'scope.  If it is
not getting up to 3 or more volts and/or does not drop to near zero volts,
it may not be properly sensed by the MCU.

You could also have a problem with marginal voltage swings on the RS-232
signal from the computer which could cause some bitsd in the data stream to
be improperly detected.  Another possible cause could be a weak MC1406 chip
in the KIO2.

73,
Don W3FPR

> -----Original Message-----
>
> Thanks, Jim.
> This is most bizarre!
> I have a scope and have checked that the rs232 signal goes right
> back to pin
> 26 on the MCU.
> I have also replaced the MCU (version 2.04P) with the previous
> version (2.03D)
> without result.
> Pieter
>

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