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Headphone DC blocking capacitors C9 and C10 have the wrong footprint. Currently they're AVE-B size which is too small for 220uf 16V parts. Suggest to find available AVE-style aluminum electrolytics on Digi-Key / Mouser, determine proper footprint and update accordingly.

Capacitor C12 (220pf RF snubber on Mic Input circuit) appears to have a smaller footprint than necessary. The schematic shows it as 0603 but comparing the pad size/spacing on the layout suggests that it's something else. As currently drawn it's too small to comfortably solder by hand.

Relocate the reference designators to prevent them from being erased during fabrication.

The microphone input circuit won't work as currently drawn. Resistors R4, R5 and R6 are on the wrong side of the DC blocking cap C11. To correct:

• R6 must connect from the positive terminal of C11 to the MIC IN pin of U1
• R4 must connect from the MIC BIAS pin of U1 to the tip pin of CONN1
• R5 must connect from the tip pin of CONN1 to GND
• negative terminal of C11 must connect to the tip pin of CONN1
• Leave C12 connected between - terminal of C11 and GND

The 3.5mm PC audio jack used for Mic / Headphone is improperly constructed.

• The hole diameter is too small for the tabs on the physical jack to fit without trimming.
• The symbol pin to footprint pin mapping is incorrect.

Because of the incorrect pin mapping,

• Tip is unconnected (should be Mic audio or Left headphone)
• Ring is connected to GND (should be PTT or Right headphone)
• Sleeve is unconnected (should be GND)

Since Ring is GND there is no way to workaround using just jumper wiring.