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Difference between revisions of "Macintosh LC 475"

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Can probably be considered the fastest model of the pizza-box LC systems. The 475 is powered by a 25MHz [[Motorola 68LC040]] processor, while the [[Macintosh LC III]] uses the [[Motorola 68030]] though clocked as fast as 33MHz.
 
Can probably be considered the fastest model of the pizza-box LC systems. The 475 is powered by a 25MHz [[Motorola 68LC040]] processor, while the [[Macintosh LC III]] uses the [[Motorola 68030]] though clocked as fast as 33MHz.
  
 +
=General Information=
 
===Video===
 
===Video===
 
Generally shipped with 512KB of VRAM via two SIMMs but can be expanded to 1MB which is required to achieve higher color and resolution.
 
Generally shipped with 512KB of VRAM via two SIMMs but can be expanded to 1MB which is required to achieve higher color and resolution.
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===Memory===
 
===Memory===
 
The 475 has 4MB onboard memory and a single 72-pin RAM slot. The maximum memory capacity is assumed to be 36MB by using a 32MB SIMM, though larger capacity RAM sticks will likely work without issue.
 
The 475 has 4MB onboard memory and a single 72-pin RAM slot. The maximum memory capacity is assumed to be 36MB by using a 32MB SIMM, though larger capacity RAM sticks will likely work without issue.
 +
 +
===Expansion===
 +
114-pin expansion slot supporting 030/040 expansion cards. Accepts Macintosh LC compatible I/O display, network, and video capture cards. Does not support
 +
030 processor accelerator or cache cards.
  
 
=Notes=
 
=Notes=
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===Capacitor replacement (power supply unit)===
 
===Capacitor replacement (power supply unit)===
 
A dead LC PSU can typically be revived by replacing all of the aluminum capacitors and cleaning up any leakage. Any working LC power supply should also be recapped as the capacitors will likely already be leaking due to component age, and the unit will eventually fail. See below for the parts list based on PSU vendor.
 
A dead LC PSU can typically be revived by replacing all of the aluminum capacitors and cleaning up any leakage. Any working LC power supply should also be recapped as the capacitors will likely already be leaking due to component age, and the unit will eventually fail. See below for the parts list based on PSU vendor.
 +
 +
'''NOTE:''' these values may differ if there happens to be multiple revisions of a certain model.
 +
 
====TDK====
 
====TDK====
 
* 1 x 180uf 385v
 
* 1 x 180uf 385v
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* 1 x 10uf 35v
 
* 1 x 10uf 35v
 
* 3 x 82uf 35v
 
* 3 x 82uf 35v
 +
====ASTEC====
 +
* 1 x 180uf 400v
 +
* 1 x 47uf 35v
 +
* 3 x 1200uf 10v
 +
* 1 x 470uf 16v
 +
* 2 x 120uf 25v
 +
* 1 x 1200uf 16v
 +
 +
=Diagrams/Schematics=
 +
[[File:Performa 400 series.png]]
  
 
=Gallery=
 
=Gallery=
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=See Also=
 
=See Also=
 
* [[Apple Computer]]
 
* [[Apple Computer]]
 +
* [[Macintosh Quadra 605]]
 +
* [[Macintosh LC III]]
 +
* [[Macintosh LC II]]
 +
* [[Macintosh LC]]
  
 +
=External Resources=
 +
* https://cdn.preterhuman.net/texts/computing/Apple_Service_PDF/68k_Macintosh/quadra_605.lc_series.pdf - Apple Service PDF
  
 
[[Category:Apple]]
 
[[Category:Apple]]

Latest revision as of 20:38, 6 November 2019

Lc475-01.jpg
43915130 280510209268868 6155856926304237038 n.jpg

Can probably be considered the fastest model of the pizza-box LC systems. The 475 is powered by a 25MHz Motorola 68LC040 processor, while the Macintosh LC III uses the Motorola 68030 though clocked as fast as 33MHz.

General Information

Video

Generally shipped with 512KB of VRAM via two SIMMs but can be expanded to 1MB which is required to achieve higher color and resolution.

Memory

The 475 has 4MB onboard memory and a single 72-pin RAM slot. The maximum memory capacity is assumed to be 36MB by using a 32MB SIMM, though larger capacity RAM sticks will likely work without issue.

Expansion

114-pin expansion slot supporting 030/040 expansion cards. Accepts Macintosh LC compatible I/O display, network, and video capture cards. Does not support 030 processor accelerator or cache cards.

Notes

  • You may need to have a PRAM battery installed in this system for the video output to work properly.
  • You can swap in a full 68040 processor as the original 68LC040 doesn't include the FPU.

Troubleshooting/Repair

Capacitor replacement (logic board)

The SMD capacitors on the logic board will most likely have already started leaking electrolyte out the bottom, and failing to replace them in a timely manner will result in further leakage with possible damage to nearby components. See below list of capacitors to replace:

  • 9 x 47uf 16V
  • 2 x 100uf 6.3V

Capacitor replacement (power supply unit)

A dead LC PSU can typically be revived by replacing all of the aluminum capacitors and cleaning up any leakage. Any working LC power supply should also be recapped as the capacitors will likely already be leaking due to component age, and the unit will eventually fail. See below for the parts list based on PSU vendor.

NOTE: these values may differ if there happens to be multiple revisions of a certain model.

TDK

  • 1 x 180uf 385v
  • 2 x 270uf 25v
  • 3 x 1000uf 10v
  • 1 x 8.2uf 50v
  • 1 x 56uf 25v
  • 1 x 47uf 25v
  • 1 x 270uf 10v

Dyna Comp

  • 1 x 180uf 400v
  • 1 x 2200uf 10v
  • 2 x 1000uf 10v
  • 1 x 330uf 35v
  • 1 x 33uf 35v
  • 1 x 10uf 35v
  • 3 x 82uf 35v

ASTEC

  • 1 x 180uf 400v
  • 1 x 47uf 35v
  • 3 x 1200uf 10v
  • 1 x 470uf 16v
  • 2 x 120uf 25v
  • 1 x 1200uf 16v

Diagrams/Schematics

Performa 400 series.png

Gallery

See Also

External Resources