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| 40m Log |
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 Fri Dec 10 15:59:23 2021, Paco, Update, BHD, Finished Coil driver (even serial number) units tests 
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 Thu Dec 16 12:21:16 2021, Anchal, Update, BHD, Coil driver test failed for S2100619-v1
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Thu Dec 16 17:41:12 2021, Koji, Update, BHD, Coil driver test failed for S2100619-v1 6x
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Thu Dec 16 15:32:59 2021, Anchal, Update, BHD, Finished Coil driver (odd serial number) units tests
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Thu Dec 16 17:57:17 2021, Anchal, Update, BHD, Finished Coil driver (odd serial number) units tests
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Mon Dec 20 14:10:56 2021, Anchal, Update, BHD, All coil drivers ready to be used, modified and tested
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Message ID: 16516
Entry time: Thu Dec 16 17:41:12 2021
In reply to: 16512
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| Author: |
Koji |
| Type: |
Update |
| Category: |
BHD |
| Subject: |
Coil driver test failed for S2100619-v1 |
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Good catch. It turned out that the both + and - side of the output stages for CH2 were oscillating at ~600kHz. If I use a capacitance sticks to touch arbitrarily around the components, it stops their oscillation and they stay calm.
It means that the phase margin becomes small while the circuit starts up.
I decided to increase the capacitances C6 and C20 (WIMA 150pF) to 330pF (WIMA FPK2 100V) and the oscillation was tamed. 220pF didn't stop them. After visually checked the signal behavior with an oscilloscope, the unit was passed to Anchal for the TF test.
The modification was also recorded in the DCC S2100619 |
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