9720 VCO assembly problem‏

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Nic Roche
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9720 VCO assembly problem‏

Post by Nic Roche »

We have finished assembling all modules. We are doing the end-to-end tests.

We are up to Testing #3 on VCO. We have roughly double the period on the modulator cycles.
  • Modulator attack midpoint - ~4 instead of 2 seconds
    Modulator release midpoint - ~10 seconds instead of 5 seconds
    Attack and Release fully clockwise - ~29 instead of 15 seconds
We have verified the correct value transistors Q4-Q6.
We have verified the wiring and resistor value on R200-R202.
We have verified the correct voltage at IC3 pin 4 (+12V) and pin 11 (-12V).

There were no other verification's listed. Was there something else we could have checked?

Also, on the next step #4 we get on AC the correct reading (1.25V) but on DC it varies wildly. These problems may be related.
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