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all I wanted to do was give PSK31 a try, and now I've got real trouble

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KC9GBX

all I wanted to do was give PSK31 a try, and now I've got real trouble

So I purchased a NUE-PSK modem kit ( I had them do the surface-mount component soldering), and after I had completed my portion of the soldering, things checked out fine.

I also ordered the cable that connects the modem to my K2, but I was informed that the cable would be shipped separately. After waiting for nearly a month without receiving the cable, I decided to make my own. I followed the generic cable-wiring diagram that NUE-PSK provided in the kit assembly manual.

My crash-scene investigation revealed that I had pumped 13.5 volts from the modem into the K2's microphone jack, pin 6, which is marked on the K2 schematic as a 5 volt line.

Now, when I push the K2's POWER ON button, I hear an initial relay click, but that's it!!!

No LCD display, no bar graph, no audio, no band or mode change occurs.

I'm hoping that I only fried the 5 volt regulator, U5, on the Control Board, but I'm pessimistic by nature! I didn't see or smell any smoke. Any ideas would be most appreciated!

It's been a great low-power rig for more than 4 years, and I'd sure like to save it!

Here's hoping, and 73, Jef Fox kc9gbx

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Don Wilhelm-4

Re: all I wanted to do was give PSK31 a try, and now I've got real trouble

Jef,

Sorry to be the bearer of bad news, but if you dumped 13.5 volts onto
the 5 volt rail in the K2, it is likely that you have either damaged or
stressed all the components that operate on the 5 volt rail.
That would be Front Panel U1, U2, U3, and U4. It is also possible that
the encoder could be damaged too. Then on the Control Board, U6, U7 and
U8 could be damaged, and possibly the 5 volt regulator U5.

These parts are logic components and do not do well when subjected to an
overvoltage condition.

If you want to do the best repair, I suggest simply replacing all those
components (except the encoder until it is proven faulty - encoder is an
expensive part). Replacing all of the suspect components is likely
easier than attempting to debug the digital signals to determine which
ones are possibly damaged. Even if some of those components work now,
their life is surely shortened, and may fail later. The parts cost is
not excessive, and I recommend replacing them all.

73,
Don W3FPR

[hidden email] wrote:

> So I purchased a NUE-PSK modem kit ( I had them do the surface-mount
> component soldering), and after I had completed my portion of the
> soldering, things checked out fine.
>
> I also ordered the cable that connects the modem to my K2, but I was
> informed that the cable would be shipped separately. After waiting
> for nearly a month without receiving the cable, I decided to make my
> own. I followed the generic cable-wiring diagram that NUE-PSK
> provided in the kit assembly manual.
>
> My crash-scene investigation revealed that I had pumped 13.5 volts
> from the modem into the K2's microphone jack, pin 6, which is marked
> on the K2 schematic as a 5 volt line.
>
> Now, when I push the K2's POWER ON button, I hear an initial relay
> click, but that's it!!!
> No LCD display, no bar graph, no audio, no band or mode change occurs.
>
> I'm hoping that I only fried the 5 volt regulator, U5, on the Control
> Board, but I'm pessimistic by nature! I didn't see or smell any
> smoke. Any ideas would be most appreciated!
>
> It's been a great low-power rig for more than 4 years, and I'd sure
> like to save it!
>
> Here's
> hoping, and 73, Jef Fox kc9gbx
>
>
>
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