KDSP2 stopped working, LED always on

[Brian - N5BCN]

My KDSP2 has been working fine up until today when I cracked open the lid of the K2 to perform a VFO dial calibration.  At some point during the process, I noticed that the KDSP2's LED was staying on.  I figured I must have bumped something, so I tried cycling the K2 on and off and re-seating the KDSP2 module (several times).  No luck, the LED stays on and when I issue KDSP2 commands the K2 reports "not inst" or something like that.

I can't imagine what I did to knock it out, but any trouble shooting tips would be appreciated.

The KDSP2 manual's troubleshooting sections says to "check U1 and D3" but I'm not sure what I'm supposed to be checking them for.

73 Brian N5BCN
 

[Phil Wheeler-2]

Perhaps read voltages in manual and compare to
what you measure. Note the conditions under which
those voltages were measured.

73, Phil w7ox

On 3/21/14, 12:38 PM, Brian - N5BCN wrote:
> The KDSP2 manual's troubleshooting sections says to "check U1 and D3" but
> I'm not sure what I'm supposed to be checking them for.
>
> 73 Brian N5BCN
>  
>

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[Don Wilhelm-4]

Brian,

Unless you unseated the DSPx module (the one on top), it is not likely
that you did anything overt to create that problem.  Treat it as a new
problem that just happened to appear.

It could be a solder connection that was marginal, or it could be that
one of the pins of the KDSP2 U1 IC became oxidized.  Try re-seating U1
to clean off any oxidation by the wiping action that results.
If that does not help, try re-flowing the soldering on the KDSP2 with a
hot (750 degF) soldering iron.

The KDSP2 will report Not Installed as long as the LED is lit, so
getting the reset signal to flow out of the KDSP2 firmware and through
the DSPx module is the first step.  Make certain the DSPx module is
placed properly in the sockets on the lower board and none of the DSPx
pins are bent.

73,
Don W3FPR

On 3/21/2014 3:38 PM, Brian - N5BCN wrote:
> My KDSP2 has been working fine up until today when I cracked open the lid of
> the K2 to perform a VFO dial calibration.  At some point during the process,
> I noticed that the KDSP2's LED was staying on.  I figured I must have bumped
> something, so I tried cycling the K2 on and off and re-seating the KDSP2
> module (several times).  No luck, the LED stays on and when I issue KDSP2
> commands the K2 reports "not inst" or something like that.
>
>

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[Brian - N5BCN]

Hi Don,

I performed a voltage test on U1 with the K2 on, DSPx module removed, coin cell batt installed.

All pins tested ok except pins 15-19 and 27 were at 5V, the spec sheet says that they should be at 0 V.  It is not obvious to me if this represents a problem per the schematic of U1.

Also, the DSPx module gets pretty warm when plugged in and the K2 is powered up.

BTW, U3 on my DSPx module is soldered directly to the board, there is no socket.

Thanks and 73,
Brian N5BCN

[Don Wilhelm-4]

Brian,

U1 Pins 15-19 and 27 are not used, so whatever voltage they may be at is
not likely to be causing any problem.

Yes, the DSPx module does draw a bit of current, so it will normally
produce some heat.  Just how much is difficult to say via email. While
it may be warm, it should not be uncomfortable to touch for 30 seconds
or more.

Do you mean U3 on the main DSP2 board?  That is the clock module, and it
is soldered in.  The only socketed device on the KDSP2 is U1.  I doubt
that U3 would cause a problem other than bad timekeeping.

73,
Don W3FPR

On 3/21/2014 6:35 PM, Brian - N5BCN wrote:

> Hi Don,
>
> I performed a voltage test on U1 with the K2 on, DSPx module removed, coin
> cell batt installed.
>
> All pins tested ok except pins 15-19 and 27 were at 5V, the spec sheet says
> that they should be at 0 V.  It is not obvious to me if this represents a
> problem per the schematic of U1.
>
> Also, the DSPx module gets pretty warm when plugged in and the K2 is powered
> up.
>
> BTW, U3 on my DSPx module is soldered directly to the board, there is no
> socket.
>
> Thanks and 73,
> Brian N5BCN
>
>
>
>
>
> --
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