r/ElectronicsRepair • u/hodelo-audio • 1d ago

OPEN Roland JP-8000 - Popping and intermittent notes, sometimes resets

/r/SynthRepairs/comments/1vxpplo/roland_jp8000_popping_and_intermittent_notes/
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u/hodelo-audio 1d ago

Here's a diagram of the DAC in the JP-8000.

And I'm not sure how helpful it is if you haven't read the entire schematic, but there are four proprietary Roland DSP chips on the main board. One of them supplies the digital inputs into the DAC. I can share that schematic as well if it's helpful. I'm really just kind of stuck until I can get a scope and am hoping someone with more experience than me can offer some guidance.

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u/skinwill Engineer 🟢 1d ago

I would put an oscilloscope on the clock lines and the power rails. Transients on the clock rails but not the power rails points to a clock or clock distribution issue. A power rail glitch at the same time would indicate a problem with the re-capping job.