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MacintoshPortable4MB RAM

2tf2294x4g-maker·MacintoshPortable4MB_RAM

MacintoshPortable4MB RAM PCB layout, top view — open source board by 2tf2294x4g-maker
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About the MacintoshPortable4MB RAM PCB

MacintoshPortable4MB RAM is an open source PCB design by 2tf2294x4g-maker, published on GitHub under the CERN-OHL-S-2.0 license. It is a 4-layer board measuring 123 × 81 mm, with 31 components from 9 distinct parts.

Other key parts include the ATF1502ASL-25AU44, AS7C4096A-12TCN and SN74HC245DW. By type, the board carries 15 capacitors, 11 ICs, 3 resistors and 2 connectors.

It belongs with the usb & debug tools designs in this gallery.

From the project

A 4MB RAM board for the Macintosh Portable using 5V SRAM

Expands a Macintosh Portable from 1 MB to 5 MB total (1 MB onboard + this 4 MB card).

This is a fully 5V design — no level shifters, no LDO regulator, no 3.3V rail. All parts are readily available and inexpensive. The board has been built and validated working in a real Mac Portable.

Full BOM with Mouser/DigiKey part numbers: BOM.csv

Upload Gerbers.zip to your preferred fab (JLCPCB, PCBWay, OSHPark, etc.).

MacintoshPortable4MB RAM, from the project README
From the project README

Main components on the MacintoshPortable4MB RAM

ATF1502ASL-25AU44AS7C4096A-12TCNSN74HC245DW

MacintoshPortable4MB RAM bill of materials (BOM)

31 components, 9 distinct parts — part numbers from the project's BOM.

QtyPartRefs
1
ATF1502ASL-25AU44
ATF1502ASL
Microchip
U1
8
AS7C4096A-12TCN
IS61WV5128BLL-10TLI
Alliance Memory
U2, U3, U4, U5, U6, U7, U8, U9
2
SN74HC245DW
74HC245
TI / Nexperia
U11, U12
1
BCS-125-F-D-HE
RAM Connector
Samtec
J1
1
JTAG_Header_2.54mm_1x06
Generic
J2
12
100NF
100nF
Generic
C1, C2, C3, C4, C5, C6, C7, C8 +4
1
100nF
Generic
C13
2
10µF
Generic
C14, C15
3
10K
Generic
R2, R3, R4

MacintoshPortable4MB RAM design files

The KiCad project lives in the 2tf2294x4g-maker/MacintoshPortable4MB_RAM repository on GitHub; these links point at the commit this page was built from.

MacintoshPortable4MB RAM: common questions

How big is the MacintoshPortable4MB RAM PCB?

The MacintoshPortable4MB RAM measures 123 × 81 mm, has 4 copper layers and is 1.625 mm thick.

How many components are on the MacintoshPortable4MB RAM?

31 components, from 9 distinct parts, with part numbers taken from the project's own BOM. The full bill of materials is listed on this page.

Where can I download the MacintoshPortable4MB RAM design files?

From the 2tf2294x4g-maker/MacintoshPortable4MB_RAM repository on GitHub, which has the KiCad layout, the schematic and the BOM; the links under Design files point to each one.

Can I use the MacintoshPortable4MB RAM design in my own project?

Yes, under the terms of its CERN-OHL-S-2.0 license, which 2tf2294x4g-maker chose for the repository.

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