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QCX20M #585 Transmitter Inoperative
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Dave Lear
I have built #585 and the receive section is working along with the display and the sub menu items. The rig aligned as per the manual. The keyer and side tone are working. ? However, the transmitter is not working. CLK0 and CLK1 are displaying quadrature wave forms. But here is no CLK2 output. I isolated IC1-pin 6 and still no output. So I decided to strip out IC1 and its associated components and substitute an Adafruit 5351 breakout board (didn’t realize that QRP Labs also has a similar breakout board). I changed the 27mHz crystal from the QCX to the Adafruit board in place of the 25mHz SMD Adafruit crystal. ? CLK0 and CLK1 are operative but still no CLK2. I disconnected pin 6 again and still no output. Since the same condition appeared in both approaches I’m suspecting IC3 may be faulty. I do have a second Adafruit board and could try the same procedure to see if an unconnected CLK2 pin would have an output. ? Any suggestions ? ? 73, Dave NE5DL |
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Arv Evans
It might be interesting if someone would write a set of test programs that supported individual function testing.? In this case the code would activate only CLK-2 on the Si5351a and thus allow signal tracing to determine if the IC was bad, wiring was bad, or configuration was bad, or possibly original software had a glitch and was not activating CLK-2.? _._ On Wed, Dec 6, 2017 at 2:42 PM, Dave Lear <de.ne5dl@...> wrote:
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Hi Dave Have you checked for a short from IC3C pins 4, 10 to Ground?? I agree, testing Clk2 when it is unconnected would be a good idea.? 73 Hans G0UPL On Thu, Dec 7, 2017 at 12:42 AM, Dave Lear <de.ne5dl@...> wrote:
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