k2 smoke test

[Dennis Vavra]

Tom,
I powered up the k2 with a laptop power supply (not a wallwart),
I thought the voltage on unit indicated 12v DC. Unfortunatually
The voltage was 120v DC. There was smoke for 1 second and I shut
down K2. Out of curiosity I plugged wallwart into K2 to see if unit
could power up. Voltage current display shows E00.1, 000.
I know this bodes ill for #06008. Dennis Vavra  AD5LY
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[Don Wilhelm-3]

Dennis,

OH MY!  That IS bad news.  It is difficult to predict what has been damaged.
There is hope that the resettable fuse protected some things, and the
regulators on the control board provided some protection too, but just how
much remains to be seen.  There is a possibility that all the active devices
were stressed, but if the regulators failed open (as opposed to shorted),
then most everything would survive.  This may be an example of the old adage
that the transistor will always protect the fuse!  Fortunately you did not
have a lot of the RF board components installed at this point, so salvage
will not be terribly bad even if you have to replace all the active devices
that are installed - worst case is that you have a long and tedious
troubleshooting session ahead of you.

Best thing to do is to STOP EVERYTHING until you obtain a good stable 13.8
volt regulated power supply rated at 5 or 6 amps or more (if you plan the
KPA100, then get a 20 amp power supply) - no more 'make-do' power supplies.
If you have a gell cell battery, that can be safely used rather than a power
supply, but you will still have to have some sort of charging supply for
that gell-cell.  Once you have that proper power supply in hand, then (and
only then) can you proceed with intelligent troubleshooting.

In the meantime, study the schematic of the K2, in particular the path for
the inbound 12 volt line so when it comes to the actual troubleshooting you
can quickly follow along with suggestions on the schematic - this is not a
situation that is covered in the normal manual based troubleshooting
section, so don't bother to look for it.

73,
Don W3FPR

> -----Original Message-----
>
> Tom,
> I powered up the k2 with a laptop power supply (not a wallwart),
> I thought the voltage on unit indicated 12v DC. Unfortunatually
> The voltage was 120v DC. There was smoke for 1 second and I shut
> down K2. Out of curiosity I plugged wallwart into K2 to see if unit
> could power up. Voltage current display shows E00.1, 000.
> I know this bodes ill for #06008. Dennis Vavra  AD5LY
>

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[list1]

Hi Dennis,
Don't lose hope.  You will be a better builder after you fix this.  If you
don't have one, get a digital volt meter.  You can probably get a decent one
for about $20.  ALWAYS check the voltage , and the POLARITY, if DC of any
power supply, including batteries before you hook them up to equipment.  If
the center of a DC power plug is supposed to be positive, it is very
important that you don't reverse the wires.

Steve, W2MY

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