[Elecraft] K2 Build Question

[tom.w3qs]

Hi Maggie,

Thank you so much for responding, I was afraid everyone was out fourthing.

I seriously hoped you were wrong about checking the soldering on U1 as the
pins are hidden by the glass-thing on the front side.

But, I dutifully checked everything again and made an absolutely ghastly
discovery!!!

I can't operate a DMM!

Seriously, I wouldn't have thought it would make a difference on resistance
checking, but I guess that is not the case.

I had done the checking by probing with the common lead while the other lead
was grounded.   I reversed the connections, and now all checks are within
normal range.  Many of the other checks are different, now, but they had
been in-range before.

Well, I guess you're never too old to learn something.  This is my first
DMM, always done it with analog meters before.

Thanks and have a great fourth!

On to the rest of the adventure!

Tom, W3QS

-----Original Message-----
From: Margaret Leber [mailto:maggie at voicenet.com] 
Sent: Saturday, July 02, 2005 11:51 AM
To: tom.w3qs
Cc: Elecraft at mailman.qth.net
Subject: Re: [Elecraft] K2 Build Question

tom.w3qs wrote:

> 1.  Resistance checks for U1 pins 1 & 2 are out of spec.  Chart says 
> 25 - 35 K for both pins.  DMM reads 17 K for both.  Old analog meter 
> reads 8 - 9 K for both.
> 
> 2.  Resistance checks for J1 pin 15 is out of spec.  Chart says 10 - 60 K.
> Analog meter reads 80 K.
> 
> Perhaps the resistance chart does not take the added SSB stuff into
account?
> U1 pin 1 and J1 pin 15 are both associated with this added circuitry.

I did the same build you did (well, on S/N 1641 anyway)...and noted the
resistance check values after adding the KSB2 components using a Triplett
2030A DMM.

U1 pins 1 & 2 : 30Kohm
J1 pin 15: 31Kohm

So whatever the reason for what you're seeing, I don't think we can blame it
on the KSB components being present. You might want to inspect things again.
It's *very* easy to overlook soldering a pin or two on the LCD or one of the
processor chips, and have things sorta almost work anyway because the pin's
in a plated-through hole making intermittant contact. I did that more than
once.

  73 de Maggie K3XS

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