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 (11)
Not yet walked against a physical board. The 94 pins and 61 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: 3C pin 7 is printed as a bare 'BANK' with no digit, and pin 2's digit is degraded (read as 2). Only 'BANK 1' is fully legible.
Extraction uncertainty: 3C pin 6's input label digit is degraded; read as DB0 from the DB2/DB1/DB0 sequence and from 9B pin 13 being clearly DB0.
Extraction uncertainty: 3C pin 1's 'CL' lettering is smudged; a bar stroke appears present but cannot be called cleanly.
Extraction uncertainty: D1/D2 part number reads 'IODI' in the hand lettering, i.e. 10D1 with the classic 1/I and 0/O ambiguity.
Extraction uncertainty: The coin connector's COUNTER 2 pin number is a single illegible glyph.
Discrepancy vs IC index: 3C IS ON THIS SHEET. The IC index placed the 74LS174 ROM bank latch on sheet 1/8, and a separate reading of 1/8 confirmed it is not drawn there. It is here, clocked by 3D's 3E00 output and feeding BANK/BANK 1/BANK 2 across to 1/8.
Discrepancy vs IC index: MAME CROSS-CHECK, derived from the drawing alone: 3D's outputs are 3800 /RGCS (palette_ext), 3900 /BCS (palette), 3A00 SOUND (soundlatch), 3B00 /SCRPO (bg scroll), 3C00 /OKOUT (MAME's "DMA trigger, not emulated"), 3D00 to the LS259, 3E00 to the bank latch, 3F00 unused. That is MAME's memory map line for line.
Discrepancy vs IC index: 9B matches MAME's LS259 bit for bit: Q0 flip, Q1 sound reset, Q2/Q3 coin counters. Q4-Q7 are drawn but carry no pin numbers and no wires.
Discrepancy vs IC index: ECLK has NO overbar; the apparent bar is the wire's corner bend. It drives 3D's active-high G1, which is consistent. SOUND and FLIP also have no bars, while /WRAM /EXTEN /CHARCS /SCRCS /INCS /RD8 /WR8 /ACLI /RGCS /BCS /SCRPO /OKOUT /SRES all do.
Discrepancy vs IC index: The sprite DMA trigger does nothing locally: /OKOUT leaves the A board on connector pin B20.
