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PubInv / NASA-COG

A control system for a highly reliable ceramic oxygen concentrator developed by NASA
GNU Affero General Public License v3.0
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5.3MM Diodes on D1, D2 Footprint Says MELF, But MELF is 3.3mm #383

Closed ForrestErickson closed 1 year ago

ForrestErickson commented 1 year ago

Summary

D1 and D2 on the October V1.1 assemblies are oversize and appear to be wrong polarity.

History

JLCPCB warned Lee that the parts had poor footprint and may not solder which Lee waved. JLCPCB and Lee had back and forth on diode polarity and they still got it wrong. Sigh....

The KiCAD library for 5.1V called out miniMELF image

This is a about a 3.3 mm part. with which the footprint work.

The JLCPCB part Lee selected was only a MELF (5.5 mm) Thus too big.

Short Term Corrective Measure.

Remove and reorente the existing part. Perhaps tomb stone it if necessary Possibly order 5.1V miniMELF and rework SN 9-13. image

Fix Root Cause

Find and change for JLCPCB miniMELF 5.1 V if available.

ForrestErickson commented 1 year ago

Change to ZMM5231 Manufacturer JSMSEMI MFR.Part # ZMM5231 JLCPCB Part # C2857227 Package MiniMELF(SOD-80) Description ±5% 500mW 5.1V MiniMELF(SOD-80) Zener Diodes ROHS

ForrestErickson commented 1 year ago

Change committed. Closing