NES Schematics

NES Schematics is a seven-sheet scan of 1989 CAD schematics: two sheets for the NES control deck mainboard and five for NES cartridge boards. Each sheet has a standard title block with a document number and date but no company name or author, so who drew them is not recorded. The scan is the one at archive.org uploaded by geneb, which gives no creator or date. They are not to be confused with the redrawn NES-001 Schematic of 2020.

Contents

Sheets, from their title blocks

PDF page	Title	Document number	Date
1	NES Motherboard Sheet 1 (sheet 1 of 2)	NESMB1.SCH, rev. A	12 July 1989
2	NES Motherboard Sheet 2 (sheet 2 of 2)	NESMB2.SCH, rev. A	29 June 1989
3	NES Type 1 Cartridge	TYP1CART.SCH, rev. A	12 July 1989
4	NES Type 2 Cartridge	TYP2CART.SCH, rev. A	12 July 1989
5	NES MMC1 Cartridge	TYP3CART.SCH, rev. A	12 July 1989
6	NES MMC2 Cartridge	TYP5CART.SCH, rev. A	date obscured on the scan
7	NES MMC3 Cartridge	TYP4CART.SCH, rev. A	12 July 1989

Sheet 1 shows the CPU (U6, "NES CPU") with its 21.4772 MHz master clock input on pin 29, the 6116 work RAM (U1), the 74LS139 decoder (U3A and U3B), the 72-pin cartridge edge connector (+5 V on pin 36, ground on pins 1, 37 and 72), and the lockout chip (U10, "NES CIC") with its 4 MHz crystal Y1, R1 (1 MΩ) and the '04 inverter sections U9A, U9B and U9F. U10 takes RESET on pin 7 and drives the system reset (SYSRES) from pin 9; its clock is on pin 6, its data lines CIC1, CIC2 and CIC10 on pins 1, 2 and 10, and pins 11 to 15 are grounded. The sheet also marks three modifications, two of them cut-and-connect changes.

Sheet 2 shows the PPU (U5, "NES PPU") with its video output going to the RF modulator, the 74LS373 address latch (U2), the 6116 video RAM, the 74LS367 controller buffers (U7 and U8) and controller connectors CN1 and CN2, the 21.47727 MHz crystal oscillator (Q2 and Q3) that makes the CPU and PPU clocks, and the console switch assembly (power switch S1, reset switch S2 and the power LED D1) on connector CN3.

What it does not contain

• Values for most passive components. The clock and reset parts carry values; the capacitors on the motherboard sheets do not.
• The RF modulator and power module, which is drawn only as a destination for the video output.
• The NES-101 top-loader, the Famicom and PAL consoles.
• A board layout, parts list or fault-finding procedure. Nintendo's fault-finding is in the Nintendo World Class Service NES Product Maintenance Troubleshooting And Service Guide and the NOA Independent Servicer Technical Training Workbook.

Pages that cite this document

• Nintendo Entertainment System: cartridge connector power pins
• Nintendo Entertainment System Troubleshooting Guide: the CIC lockout chip's pins

Download: NES Schematics.pdf