Nintendo Game Boy Technical Manual

The Game Boy Technical Manual is Nintendo of America's World Class Service binder for the original Game Boy (DMG), issued to authorised service centres. The title page is marked "Confidential" with a 1991 Nintendo copyright, and the back cover gives the address of Nintendo of America's National Field Service Department in Redmond, Washington. It covers the Game Boy at board level, with a full schematic, a parts list with component values, a diagnostic table and the service bulletins, along with the Game Paks, the Rechargeable Battery Pack and the Four Player Adapter.

The scan is 116 PDF pages, including the covers, the change record and the tab dividers. It is byte-identical to the copy uploaded to the Internet Archive on 10 January 2025, whose uploader describes it as a binder from a former World Class Service station, with a small gold sticker on the back cover reading "Man. technical DMG #21530".

Revisions

Each page carries its own revision date, and pages were replaced individually as Nintendo issued updates. The front matter and most of the Game Boy section are Rev. 11/91; the exploded views, parts list and wire routing pages are Rev. 11/93; the diagnostic table and burn-in page are Rev. 02/92; the test fixtures are Rev. 06/92; and the newest pages, the Game Pak reference table (3-3) and the Donkey Kong (3-6.1) and Wario Land (3-26.1) pages, are Rev. 09/94. The change record sheets are blank. Cite a figure by page number and that page's revision.

Contents

Contents of the binder

Section	Pages	What it holds
1 System Overview	1-1 to 1-2	Hardware summary of the Game Boy, Game Link cable, Rechargeable Battery Pack, Four Player Adapter and Game Paks
2 Game Boy	2-1 to 2-26	Theory of operation (2-1, 2-2); block diagram; power distribution (2-5); exploded views (2-6, 2-7); parts list for model 18404 (2-8 to 2-10); schematic of the CPU, LCD, small jack and DC/DC converter boards with the Game Link cable wiring (2-11, scanned across two PDF pages, the second upside down); wire routing and board interconnections (2-12 to 2-15); CPU board component layout (2-16); test procedure (2-17); disassembly and LCD board replacement (2-18 to 2-24); diagnostic table (2-25, 2-26)
3 Game Paks	3-1 to 3-37	Cartridge construction; Game Pak reference table; one page per game, from Alleyway to Yoshi's Cookie, giving its board and chips; board layouts; Game Pak test procedure and diagnostic table
4 Rechargeable Battery Pack	4-1 to 4-7	Operation, wiring diagram, test procedure and diagnostic table
5 Four Player Adapter	5-1 to 5-6	Operation, diagram and test procedure
6 Test Fixtures	6-1 to 6-4	The Game Boy test cartridge and how to use it
7 IC Functions & Specifications	7-1 to 7-2	Handling notes on ICs only
8 Burn-in Station	8-1	Run every repaired unit with a game for at least eight hours, using the Rechargeable Battery Pack as the 5 V supply, then test it with the test cartridge
9 Service Bulletins	–	Bulletins 90289, 90290, 90291, 91154, 91197 and 91353, some filed twice
10 Appendix A	10-1	Glossary; filed in this scan between sections 3 and 4

Figures in the manual

• DC/DC converter input 3.5 to 7 V DC, from four AA cells or the Rechargeable Battery Pack (1-1, 2-1). Outputs: +5 V (VDD) for the CPU board, 4.6 to 5.4 V, and −18 V (VEE) for the LCD, −16 to −20 V (2-5). A normally closed switch in the power jack disconnects the batteries when a plug is inserted (2-1).
• Master clock 4.194 MHz; the parts list gives the crystal as 4.194304 MHz (2-2, 2-9).
• The LCD buffer amplifier IR3E02 on the LCD board provides the LCD bias voltage and contrast control through VR1 (1-1, 2-11).
• The CPU is the LR35902; the work RAM and video RAM are 64K SRAMs at U3 and U2; the sound amplifier is U4 (IR3R40) (2-8, 2-11).
• The parts list gives values and quantities by board but not by designator: the CPU board has two 100 µF 10 V, two 10 µF 16 V and two 1 µF 50 V electrolytics, the small jack board two 100 µF 6.3 V, and the LCD board two 100 µF 10 V and one 10 µF 25 V (2-8 to 2-10). Designators are on the schematic. Many items are marked as not available as spare parts.
• The volume control is a dual 10 kΩ potentiometer on the CPU board and the contrast control a single 30 kΩ potentiometer on the LCD board (2-8, 2-10, 2-11). The price list in Nintendo's Japanese service manual labels them the other way round and gives the single one as 300 kΩ.

The diagnostic table (2-25, 2-26) tells the technician to inspect the boards first, to isolate the faulty half by substitution with a known-good unit, and not to try to clean the 32-pin connector (P1) but to replace it if it is contaminated.

Service bulletins in the binder:

Service bulletins

Bulletin	Subject
90289	CPU versions 0, A and B need different C21 and C22 values: 15 pF for an unmarked CPU, 27 pF for version B, either for version A. Check them when replacing the CPU.
90290	Units up to serial G03100000 had rear housings that let batteries make contact when fitted backwards, which with some brands made them leak; a new rear housing prevents it.
90291	LCDs on units up to serial G02800000 develop black or missing lines after use. Affected parts are identified by a lot number printed in white on the LCD driver IC; the LCD was replaced once under warranty.
91154	Units G11200000 to G14000000 with a Sharp LH5168NFA-10L SRAM at U2 (VRAM): add a 100 pF capacitor between SRAM pins 9 and 14 to cure poor scrolling.
91353	The screen cover gasket (part 21105), which seals the front housing to the LCD against dust.
91197	An NES bulletin, filed in this binder: NES Game Paks with battery backup and an NEC-made MMC1 may not save.

What it does not contain

• Nothing on the Game Boy Pocket, Light, Color or Advance. For the Game Boy Color see Nintendo Game Boy Color Service Manual; for the Advance, Game Boy Advance Service Manual.
• No component layout for the LCD, small jack or DC/DC converter boards; page 2-16 covers the CPU board only.
• The Game Boy test cartridge in section 6 was a service fixture and was not sold.

Download: Nintendo Game Boy Technical Manual.pdf (75 MB)

Related pages

• Nintendo Game Boy Service Manual (Japanese)
• Nintendo Game Boy Color Service Manual
• Game Boy Advance Service Manual
• Nintendo World Class Service NES Product Maintenance Troubleshooting And Service Guide
• List of Nintendo Hardware