Click a net label to trace it — endpoints colour-coded input · output · in/out — click an IC box (either panel) to select it in both, click again to deselect (multi-select OK), Esc clears all. Use the IC rail on the far left to jump straight to a chip. A net name shown muted like this and prefixed $ is ours - a node the 1985 drawing leaves unlabelled; every other name was read off the drawing. Hover a pin for its net's story.
Notes and open questions on this sheet (24)
Not yet walked against a physical board. The 172 pins and 75 nets on this sheet were read from the original drawing and cross-checked against MAME; every IC is still marked auto. Part numbers and pin assignments are what the drawing shows, not what has been metered.
Extraction uncertainty: 13K pin 28 read as /E2; the digit is overlapped by the module outline and could be 3. The overbar is unambiguous. Worth a bench check.
Extraction uncertainty: YM3014 pin 7 read as RB - the classic B/8 glyph trap at this scan resolution.
Extraction uncertainty: 13K pin 24 read as C0 (C-zero), the zero's slash touching the module outline.
Discrepancy vs IC index: SOUND BUS SCOPING (our decision, not the drawing's): this section's buses are printed plainly as A0-A14 and D0-D7, the same strings the 6809 uses. Modelled as $SA*/$SD* so they cannot false-join the main CPU bus; each pin keeps the printed name. Same class of bug as the SA0-SA6 false join on the sister project.
Discrepancy vs IC index: DUPLICATE DESIGNATOR R33: appears twice on this sheet, once as a 4.7K mixer resistor on 13E's SSG output and once as the 33K from the HA13001 input to GND. One is a drafting error; both are recorded as printed.
Discrepancy vs IC index: 13E and 14E pin 37 are labelled A0 yet carry an inversion bubble and are driven by module outputs named /S0 and /S2. Recorded as drawn: the module presents an already-decoded, active-low register select rather than a raw A0.
Discrepancy vs IC index: No RAM IC appears on this sheet, yet MAME maps sound RAM at C000-C7FF, so the 2K must be inside the 13K module.
Discrepancy vs IC index: A15 is never brought out of 13K, consistent with a 32K ROM at 0000-7FFF.
Discrepancy vs IC index: 13K pin numbers run to 60 but only 38 pins are drawn on this sheet.
Discrepancy vs IC index: 12H has no VCC or GND pin drawn.
Extraction uncertainty: 13K pin 28 read as /E2; the digit is overlapped by the module outline and could be 3. The overbar is unambiguous. Worth a bench check.
Extraction uncertainty: YM3014 pin 7 read as RB - the classic B/8 glyph trap at this scan resolution.
Extraction uncertainty: 13K pin 24 read as C0 (C-zero), the zero's slash touching the module outline.
Discrepancy vs IC index: SOUND BUS SCOPING (our decision, not the drawing's): this section's buses are printed plainly as A0-A14 and D0-D7, the same strings the 6809 uses. Modelled as $SA*/$SD* so they cannot false-join the main CPU bus; each pin keeps the printed name. Same class of bug as the SA0-SA6 false join on the sister project.
Discrepancy vs IC index: DUPLICATE DESIGNATOR R33: appears twice on this sheet, once as a 4.7K mixer resistor on 13E's SSG output and once as the 33K from the HA13001 input to GND. One is a drafting error; both are recorded as printed.
Discrepancy vs IC index: 13E and 14E pin 37 are labelled A0 yet carry an inversion bubble and are driven by module outputs named /S0 and /S2. Recorded as drawn: the module presents an already-decoded, active-low register select rather than a raw A0.
Discrepancy vs IC index: No RAM IC appears on this sheet, yet MAME maps sound RAM at C000-C7FF, so the 2K must be inside the 13K module.
Discrepancy vs IC index: A15 is never brought out of 13K, consistent with a 32K ROM at 0000-7FFF.
Discrepancy vs IC index: 13K pin numbers run to 60 but only 38 pins are drawn on this sheet.
Discrepancy vs IC index: 12H has no VCC or GND pin drawn.
Extraction uncertainty: 13K is 71.8% of page HEIGHT / 5.74% of page AREA. CONFIRMED LEGITIMATE - see notes.
Extraction uncertainty: 14H (27256) is 32.3% of page height and 12H ('374) 18.4%; both are single drawn rectangles, tall because their pin lists are long.
BOARD FACT, confirmed by Robert against a factory Capcom board: the five ROM slots in column N are silkscreened 8N, 9N, 10N, 12N and 13N. Capcom's designators here are LABELS, not grid coordinates - the slot labelled 10N physically sits level with the 6809 at 11L, and 12N level with the sound CPU. On Robert's board 8N, 10N and 12N are fitted (27256, 27128, 27256) and 9N and 13N are empty. Three 32K and two 16K parts, 128K in total, which is the parent `gng` ROM set - and the board is confirmed to run it. The board-photo positions for these slots are pinned to their measured centres rather than derived from the grid, because the grid cannot express this.
