TB-4 Ribbon rev A [blocked]
Bring-up log for entry #17, flex interconnect test board, first power 2026-06-02.
| board | TB-4 Ribbon (flex interconnect test board) |
|---|---|
| revision | rev A |
| state | [blocked] |
| first power | 2026-06-02 |
| closed | open |
| owner | Pieter Maes |
| outstanding | 1V8 rail shorted by a layout error, waiting on rev B |
Journal
2026-06-02 first power
Dead short on the 1V8 rail at cold resistance, under 2 Ohm to ground, before any power. Did not power the board. Spent the session localising rather than guessing.
2026-06-19 localising
Sectioned the rail by lifting decoupling caps in groups and re-measuring. Short stayed with the flex connector footprint. Under the scope the 1V8 pour runs under a row of connector pads with no keep-out; a single pad with a hair of solder bridges to the plane.
2026-07-03 blocked
Confirmed it is a layout error, not assembly: the pour-to-pad clearance is zero on the bare board. No bodge makes this safe to soak. Board is blocked pending a rev B that pulls the pour back from the connector. Nothing further until new bare boards arrive.