Grok Bot

@@ -84,3 +84,22 @@ Adom boards follow the Adom molecule standard, which the first brief left out, s | issues | 9 (1 medium) | 6 (2 medium) | 4 (all low) |  The J4 number was real copper, not a display quirk: the solve log showed /VOUT reaching J4 only through its 0.26 mm back-side ring, with no path to the rest of the net. Grok widened the /VOUT copper at J4 and added vias, and /VOUT then solved as one piece over 89.5 mm². U1 runs warmer because the board has half the copper; it stays inside Grok's 40 °C budget. ERC 0, DRC 0 violations and 0 unconnected, the molecule check passes, all silkscreen is at least 1.0 mm, and every contact is labelled on both faces. Grok still lists two necks worth widening (/GND 18.1 A/mm² beside U1, /VIN 17.0 A/mm² from C4) and four low issues (a ground loop through J2 and J5, no TVS on VIN, EN or VOUT). **A miss Grok did not catch: the switch node.** John found it by looking at the board, and had to prompt for it. Grok wrote its own Fields spec with loads only on /VIN, /VOUT and /GND, so the SW net between U1 and L1, the one copper path carrying the full inductor current at 500 kHz, was never solved, and Grok reported "4 low issues" without ever flagging it. /SW was one 0.6 mm track, 11.2 mm long; solved as a 1 A load it peaks at 62 A/mm² and raises a medium current-neck. This is a failure of Grok's engineering judgement (the AI checking Grok's work missed it too); the fix is in clip 7. Played on the office GPU at 60 fps. 53 s. [Download](clips/06-molecule.mp4) · [captions](clips/06-molecule.vtt)++### 7. The switch node John caught++::adom-video{src="/adom/grok-bridge/render/first-ai-pcb/clips/07-sw-and-pours.video.json"}++**This one is a failure of Grok's, found by a human.** John looked at the molecule and saw that the switch node, the copper from the TPS54202's SW pin to the inductor, was a skinny track carrying the whole inductor current, and asked what happened to its analysis. Grok had written its own Adom Fields spec with loads only on /VIN, /VOUT and /GND, so /SW was never solved, and Grok had reported the board as having four low issues. Solved as a 1 A load, /SW peaked at 62 A/mm², a medium current-neck. Grok did not identify the most important current path on a buck converter on its own; it had to be prompted.++Once prompted, Grok checked both findings against the saved board (the back was mostly GND already, but a VIN track and an EN track cut it under the switching loop), worked the fix out on a scratch copy, then made it in KiCad on its own screen:++| | before | after |+|---|---|---|+| /SW | 0.6 mm track, 11.2 mm long, no pour; 62.0 A/mm² | L1's SW pad 0.8 mm from U1, a 15.6 mm² pour; 29.1 A/mm² (about 33 at the ripple peak) |+| back copper | GND, cut by a VIN and an EN track under the loop | one solid 605 mm² GND plane; R4 moved, EN rerouted on top, 4 more GND vias at U1 |+| U1 rise, still / moving | +23.9 / +15.2 °C | +23.6 / +15.0 °C |+| /VIN peak | 17.0 A/mm² | 21.3 A/mm² (worse) |+| hottest spot | +29.6 °C | +30.5 °C (worse) |+| EMC margin | 48.1 dB | 48.1 dB (the C4 input loop is unchanged) |++ERC 0, DRC 0 violations, 0 unconnected, 0 parity. Grok then walked through every pour on its desktop, one zone at a time with its net highlighted, on the top and then the bottom copper: GND (the return for every capacitor, the GND contacts and the corner pins; the back plane is cut only by a 1.8 mm VIN stub at J1 and the VOUT island), /SW (top only, no vias), /VOUT on top (54.6 mm², L1 through C7/C8 to J4) and the 20.6 mm² VOUT island on the back that feeds J4 through four vias. Its first pass lost the net highlight on the bottom views, so it redid those; the redo is shown as stills. Fields still raises a medium "no-reference" issue on /SW, which Grok argues is a tool bug (0 mm² at (0, 0)); that is filed for checking on [adom/adom-fields#13](https://wiki.adom.inc/adom/adom-fields/issues/13). 54 s. [Download](clips/07-sw-and-pours.mp4) · [captions](clips/07-sw-and-pours.vtt)

@@ -0,0 +1,22 @@+[+ {+  "t": 0,+  "title": "John's catch"+ },+ {+  "t": 16.7,+  "title": "62 A/mm\u00b2"+ },+ {+  "t": 22.1,+  "title": "The fix"+ },+ {+  "t": 33.5,+  "title": "The pours"+ },+ {+  "t": 45.3,+  "title": "What got worse"+ }+]\ No newline at end of file

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@@ -0,0 +1,51 @@+1+00:00:00,000 --> 00:00:01,700+John caught what Grok missed.++2+00:00:01,820 --> 00:00:09,000+Looking at the board, he saw that the+switch node, the copper between the+TPS54202 and the inductor, was a skinny+track carrying the full inductor current.++3+00:00:09,150 --> 00:00:16,600+Grok had never loaded that net in its+Fields spec, so it was never solved, and+Grok never flagged it.++4+00:00:16,750 --> 00:00:21,900+Solved, it peaked at 62 A/mm².++5+00:00:22,090 --> 00:00:28,300+Once prompted, Grok moved the inductor+right beside U1, and turned the switch+node into a short, wide pour.++6+00:00:28,420 --> 00:00:29,400+It drops to 29.++7+00:00:29,520 --> 00:00:33,300+The back is now one solid ground plane.++8+00:00:33,490 --> 00:00:41,700+Then Grok walks through every pour on its+own screen: ground, the switch node, on+top only, the 5 V output on top,++9+00:00:41,830 --> 00:00:45,200+and the small output island that feeds J4+from the back.++10+00:00:45,340 --> 00:00:52,460+DRC is clean, and Grok still lists what+got worse: the input track and the hottest+spot each rose a little.

@@ -0,0 +1,28 @@+{+ "video": "/adom/grok-bridge/render/first-ai-pcb/clips/07-sw-and-pours.mp4",+ "title": "Clip 7: the switch node John caught",+ "poster": "/adom/grok-bridge/render/first-ai-pcb/clips/07-sw-and-pours.jpg",+ "chapters": [+  {+   "t": 0,+   "title": "John's catch"+  },+  {+   "t": 16.7,+   "title": "62 A/mm\u00b2"+  },+  {+   "t": 22.1,+   "title": "The fix"+  },+  {+   "t": 33.5,+   "title": "The pours"+  },+  {+   "t": 45.3,+   "title": "What got worse"+  }+ ],+ "captions": "WEBVTT\n\n00:00:00.000 --> 00:00:01.700\nJohn caught what Grok missed.\n\n00:00:01.820 --> 00:00:09.000\nLooking at the board, he saw that the\nswitch node, the copper between the\nTPS54202 and the inductor, was a skinny\ntrack carrying the full inductor current.\n\n00:00:09.150 --> 00:00:16.600\nGrok had never loaded that net in its\nFields spec, so it was never solved, and\nGrok never flagged it.\n\n00:00:16.750 --> 00:00:21.900\nSolved, it peaked at 62 A/mm\u00b2.\n\n00:00:22.090 --> 00:00:28.300\nOnce prompted, Grok moved the inductor\nright beside U1, and turned the switch\nnode into a short, wide pour.\n\n00:00:28.420 --> 00:00:29.400\nIt drops to 29.\n\n00:00:29.520 --> 00:00:33.300\nThe back is now one solid ground plane.\n\n00:00:33.490 --> 00:00:41.700\nThen Grok walks through every pour on its\nown screen: ground, the switch node, on\ntop only, the 5 V output on top,\n\n00:00:41.830 --> 00:00:45.200\nand the small output island that feeds J4\nfrom the back.\n\n00:00:45.340 --> 00:00:52.460\nDRC is clean, and Grok still lists what\ngot worse: the input track and the hottest\nspot each rose a little.\n"+}\ No newline at end of file

@@ -0,0 +1,43 @@+WEBVTT++00:00:00.000 --> 00:00:01.700+John caught what Grok missed.++00:00:01.820 --> 00:00:09.000+Looking at the board, he saw that the+switch node, the copper between the+TPS54202 and the inductor, was a skinny+track carrying the full inductor current.++00:00:09.150 --> 00:00:16.600+Grok had never loaded that net in its+Fields spec, so it was never solved, and+Grok never flagged it.++00:00:16.750 --> 00:00:21.900+Solved, it peaked at 62 A/mm².++00:00:22.090 --> 00:00:28.300+Once prompted, Grok moved the inductor+right beside U1, and turned the switch+node into a short, wide pour.++00:00:28.420 --> 00:00:29.400+It drops to 29.++00:00:29.520 --> 00:00:33.300+The back is now one solid ground plane.++00:00:33.490 --> 00:00:41.700+Then Grok walks through every pour on its+own screen: ground, the switch node, on+top only, the 5 V output on top,++00:00:41.830 --> 00:00:45.200+and the small output island that feeds J4+from the back.++00:00:45.340 --> 00:00:52.460+DRC is clean, and Grok still lists what+got worse: the input track and the hottest+spot each rose a little.