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Lost triggers, TP1 at 0.2v

Posted: Jun 29th, '20, 12:14
by whomper
Hi,

When powering on the unit today, after it has been working well for a few days (other than CP and PC2) I noticed I'm getting no triggers. Testing TP1 I see ~0.2v and PIN3 of IC6 is at 0.06V. It seems its not enough to generate triggers to the sound modules.

Not sure how it happened.

Can someone measure their voltages at PIN3 or IC6 and let me know what should be the expected voltage coming in from MCP4822?
All sequencer functions seem to work well, so I'm not sure its the main chip.

Re: Lost triggers, TP1 at 0.2v

Posted: Jun 30th, '20, 13:11
by whomper
Further testing indicate that MCP4822 pin8 is outputting around 0.06v and not the reference voltage of 2v (or 4v in case the DAC is instructed to issue the double voltage). This could be due to a defective MCP4822.