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Bad PCM1702 or AD823?
Bad PCM1702 or AD823?
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Old 10th October 2019, 02:40 AM   #1
astouffer is offline astouffer  United States
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Default Bad PCM1702 or AD823?

I'm working on somewhat of a strange high end DAC with a problem. Each channel has two PCM1702s that feed into an AD823 for the I/V conversion. One output from the AD823 looks great with a sinewave playing and one side looks terrible.

How can I tell if the PCM1702 is bad or the AD823? With no signals coming into the AD823 each output is nearly at 0v (5mv offset). Anyhow here is what the two AD823 outputs look like.
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Old 10th October 2019, 02:48 AM   #2
rayma is offline rayma  United States
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The odds are it's the PCM1702. Everything is soldered in?
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Old 10th October 2019, 03:26 AM   #3
astouffer is offline astouffer  United States
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rayma, thank you for the quick reply. Yes everything is soldered in. My suspicion was leaning towards the PCM1702 as well. The components and build quality are great but the pcb itself is fragile. On a previous repair I cut all the pins from the chip and removed them separately.
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Old 10th October 2019, 03:33 AM   #4
rayma is offline rayma  United States
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Then that's what I'd do, but use a moderately dull cutter to reduce stress on the board.
Good luck. No plated through holes?

Last edited by rayma; 10th October 2019 at 03:37 AM.
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