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I hoping for suggestions on what might be the most likely culprit(s) to check. Output is good on all bands:

• 6m - 0.5 watts
• 10m - 3
• 12m - 4
• 15m - 4.5
• 17m - 2.5
• 20m - 3.5
• 30m - 4.5
• 40m - 4.5
• 60m - 4
• 80m - 6
• 160 - 7

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John AE5X

Hi John,

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my QMX showed similar behaviour. I was able to trace the receive signal with my oscilloscope up to the input of the PCM1804 and everything was fine there.

There was also digital out, but after replacing the PCM1804 everything was fine.

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This IC seems to be the weak point of the design.

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Dirk??? DK7CVD

I don't have my QMX+ kit yet, but is the? PCM1804 close to any of the really high heat ground component leads? With the high casualty rate I'm wondering if this thing is getting overheated during assembly, since the ground plane does suck up a lot of heat I'm wondering if it's killing surrounding components.

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One of the finals right next to the power input transformer also was dead at first test on my QMX , I'm wondering if we're all killing components while trying mount the devices with higher heat capacities.?

On Tue, Aug 20, 2024 at 01:48 PM, Dirk wrote:

I was able to trace the receive signal with my oscilloscope

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I sold my oscope in a moment of temporary (I hope) foolishness.

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John AE5X