jd_wages
Mac 128k Logic Board - Top
STOCK CONDITION This photo above presents the original Macintosh logic board with 128k of RAM and the 64k ROM, designed by Burrell Smith at Apple. The board was housed inside a stock Macintosh 128k, serial number F4060B5M0001 built the 6th week of 1984. The two ROM chips show part numbers: 342-0220-A & 342-0221-A.
HISTORY For a fascinating look into the design of this first Mac, I highly recommend this Feb. 1984 Byte magazine article, An Interview: The Macintosh Design Team. Steve Jobs, Bill Atkinson, Andy Hertzfeld, Larry Kenyon, Joanna Hoffman, Burrell Smith, Dave Egner, Chris Espinosa, Steve Capps, Jerry Manock, and Bruce Horn reveal how their magical computing innovation was born. Numerous in-depth stories on the making of the Mac can be found at Andy Hertzfeld's Folklore site.
MAINTENANCE With most 128k logic boards now over 25 years old, it is necessary to replace all 3 axial electrolytic capacitors used to ensure proper operating performance:
C22 (black) = 4.7uF, 35V, Axial, D=5.2mm, L=12.6mm, Lead Spacing=20mm (Tantalum replacement: 173D475X9050X)
C5 & C20 (blue) = 33uF, 16V, Axial, D=5.2mm, L=12.6mm, Lead Spacing=20mm (Tantalum replacement: T322E336K025AT. Alternatively, you can use lower cost radial electrolytic capacitors with their legs spread: UPV1V330MGD1TA.)
Axial Tantalum replacements are the most attractive looking and they will last the life of the circuit board, but they are also expensive. If you want replacement capacitors that are much lower cost and that will not need to be replaced for another 20 years, Radial aluminum electrolytic capacitors rated at 5000 hours @105°C will work, and they can be laid flat on the board to fit with their legs spread.
I have a complete list of replacement capacitors for the Analog Boards on my Google Docs Spreadsheet.
Also checkout my video on YouTube: Macintosh 128K~Plus Analog Board Recapping Walkthrough
And don't forget there's a capacitor inside the keyboard that needs to be replaced too. Here's my recommended replacement: 173D105X9050VWE3.
Mac 128k Logic Board - Top
STOCK CONDITION This photo above presents the original Macintosh logic board with 128k of RAM and the 64k ROM, designed by Burrell Smith at Apple. The board was housed inside a stock Macintosh 128k, serial number F4060B5M0001 built the 6th week of 1984. The two ROM chips show part numbers: 342-0220-A & 342-0221-A.
HISTORY For a fascinating look into the design of this first Mac, I highly recommend this Feb. 1984 Byte magazine article, An Interview: The Macintosh Design Team. Steve Jobs, Bill Atkinson, Andy Hertzfeld, Larry Kenyon, Joanna Hoffman, Burrell Smith, Dave Egner, Chris Espinosa, Steve Capps, Jerry Manock, and Bruce Horn reveal how their magical computing innovation was born. Numerous in-depth stories on the making of the Mac can be found at Andy Hertzfeld's Folklore site.
MAINTENANCE With most 128k logic boards now over 25 years old, it is necessary to replace all 3 axial electrolytic capacitors used to ensure proper operating performance:
C22 (black) = 4.7uF, 35V, Axial, D=5.2mm, L=12.6mm, Lead Spacing=20mm (Tantalum replacement: 173D475X9050X)
C5 & C20 (blue) = 33uF, 16V, Axial, D=5.2mm, L=12.6mm, Lead Spacing=20mm (Tantalum replacement: T322E336K025AT. Alternatively, you can use lower cost radial electrolytic capacitors with their legs spread: UPV1V330MGD1TA.)
Axial Tantalum replacements are the most attractive looking and they will last the life of the circuit board, but they are also expensive. If you want replacement capacitors that are much lower cost and that will not need to be replaced for another 20 years, Radial aluminum electrolytic capacitors rated at 5000 hours @105°C will work, and they can be laid flat on the board to fit with their legs spread.
I have a complete list of replacement capacitors for the Analog Boards on my Google Docs Spreadsheet.
Also checkout my video on YouTube: Macintosh 128K~Plus Analog Board Recapping Walkthrough
And don't forget there's a capacitor inside the keyboard that needs to be replaced too. Here's my recommended replacement: 173D105X9050VWE3.