Re: DDS Module is not functioning

William Kimber

HI John,

I'm with Jim on this.   A dry joint or possibly a very small bead of solder  shorting traces or pins on DDS chip.  Hope its not the module.


On 01/09/15 05:09, n5ib@... [PHSNA] wrote:

Notice that the D7 pin is adjacent to a ground pin, and the W-CLK is on the other side of the D7.
Perhaps the plug/unplug cycles have messed up something in the area of the pins.Maybe stirred up a solder splash that creates a short. Do a resistance check to ground, inspect under high magnification, and reflow the solder joints in that area.

Jim, N5IB

---In PHSNA@..., wrote :


Did some more testing on the Arduino and main board, trying to replicate the pulses shown in your photos on this topic.

I found that, with the AD9851 pulled from the main board, the pulses acted pretty much the same as your photos and had levels of about 5 v.  From that, I conclude that the Arduino is probably working as it should be.

I then replaced the AD9851 and powered it up.  At that point, I found that the D7 and W-CLK lines had multiple pulses as before but the levels on these lines were only around 0.2 v.  My guess is that something is holding these two lines to a low level.

Next step seems to be to try a new AD9851, unless you can think of another explanation.

Thanks for the help.

John, W5IDA

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