Re: T1 Tuner Kit Control Board final check issues

Posted by Don Wilhelm-5 on May 23, 2021; 11:11pm
URL: http://elecraft.85.s1.nabble.com/T1-Tuner-Kit-Control-Board-final-check-issues-tp7669742p7669743.html

Erik,

Check and double check the orientation of the diodes.  That is the most
likely reason for you measurement results.

73,
Don W3FPR

On 5/23/2021 5:39 PM, Erik Tkal wrote:

> I just assembled the T1 kit, but am having an issue in the final check phase of the Control Board.
>
> "Resistance across capacitor C19: between 137 K-ohms and 148 K-ohms. Press S2 and confirm reading drops to between 117 K-ohms and 135 K-ohms.”
>
> I’m getting around 60K or 43K with my Fluke 117, depending on which way I connect the leads.  Each of R10 and R11 individually test ok, and I don’t see any solder bridges or missing joints, and I’ve reflowed anything suspicious that might be related.  Has anyone seen this or could offer an explanation before I start pulling parts or digging out the oscilloscope?
>
> The second check is also off.
>
> "Resistance between D3 anode (end without the band) and the “ –“ pad near D7 (ground) where the black wire is attached: > 100 K-ohms (may show open or infinite on some DMMs). Press S1 and confirm the reading drops to between 117 K-ohms and 130 K-ohms. If the resistance is higher, try reversing your DMM leads.”
>
> Attaching the red lead to D3 shows infinite resistance and pressing S1 reads 170K.  Reversing shows about several M-ohm initially, but then pressing S1 gives 180K.  Note that if I use normal automatic ranging it won’t get a lock on the second S1 measurement (with black lead on D3 and red on Ground), I had to use manual range.  This makes me think the DMM circuitry may be interfering in some way.
>
> The third check on the LED voltage drop succeeds,
>
>

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