[Elecraft] KDSP2 - LED REMAINS ON

[Carl Morris, WN3DUG]

      From:  "Chris Page" <g4bue at adur-press.co.uk>
      Date:  Sat, 29 Jan 2005 23:04:44 -0000

I have just built the KDSP2 and everything seems to work properly,
including the clock and changing the filter frfequencies.

However, the red LED remains on.  I have checked U1, D3 and that the
DSPx module is properly aligned, as suggested in the troubleshooting
section, and am now a bit puzzled - if there is a problem with the
LED, why does the filter appear to work ok?

Any help and suggestions will be welcome, please.

Thanks and 73 de Chris, W4/G4BUE

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Chris,
I think Lyle is out of town, but here is his suggestion for
someone else who had this problem before, that may help.

72/73, Carl, WN3DUG
cwmorris at pa.net
K2/100, KX1

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Re: [Elecraft] K2 DSP Problem
      from [Lyle Johnson] [Permanent Link][Original]

      To:  J F <phriendly1 at yahoo.com>
      Subject:  Re: [Elecraft] K2 DSP Problem
      From:  Lyle Johnson <kk7p at wavecable.com>
      Date:  Thu, 13 Jan 2005 09:39:47 -0800
      List-post:  <mailto:elecraft at mailman.qth.net>

      > Finally had a chance to work on some of my kits.
I had completed the DSP kit and just now am installing
it.
        No smoke
That's good!

        but the red LED remains on.
That's not so good.

>...
> Any suggestions?
      The LED comes on when the DSPx resets, and goes off when it handshakes 
with U1 on the KDSP2 board.

      Do you have any audio? If so, this indicates the DSPx is initializing 
and the problem might be associated with the LED circuity or U1.

      Can you get a display by pressing AFIL? SF2 or CF2 depending in mode, 
for example. If so, this indicates that U1 is probably working and there may 
be a PCB problem or a DSPx problem. If not, U1 may be the culprit.

      If you can safely probe J1 20 (on the DSPx while plugged into the K2 
and switched on) you should see that pin 20 (DSPx reset) is pulsed to ground 
at turn-on, then rises to something over 3V. If it stays low, the DSPx is 
always being held in reset. If it never goes low, the DSPx is not getting 
reset.


73,

Lyle KK7P
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