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Macintosh LC III: Difference between revisions
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The LC III is powered by a 25MHz [[Motorola 68030]]. Apple also released the LC III+ which is essentially the same system but the board was altered to increase the clock speed to 33MHz. The LC III does not include a math co-processor but a socket is available to install a [[Motorola 68882]]. | The LC III is powered by a 25MHz [[Motorola 68030]]. Apple also released the LC III+ which is essentially the same system but the board was altered to increase the clock speed to 33MHz. The LC III does not include a math co-processor but a socket is available to install a [[Motorola 68882]]. | ||
=General Information= | |||
At some point during the production run it seems that the case design was changed from the traditional LC front panel to what was used in the [[Macintosh LC 475]]. | At some point during the production run it seems that the case design was changed from the traditional LC front panel to what was used in the [[Macintosh LC 475]]. | ||
The LC III replaces the [[Macintosh LC II]] and is the last of the [[Motorola 68030]] based "pizza box" LCs, as the [[Macintosh LC 475]] used the [[Motorola 68LC040]]. | The LC III replaces the [[Macintosh LC II]] and is the last of the [[Motorola 68030]] based "pizza box" LCs, as the [[Macintosh LC 475]] used the [[Motorola 68LC040]]. | ||
===Expansion=== | |||
The LC III supports LC PDS expansion cards from the earlier LCs, but it also supports specific LC III PDS cards made for the larger data path of this system. The physical expansion slot is larger on the LC III to support these cards. | |||
=Notes= | =Notes= | ||
* Like almost all Macs of this era, you must recap the board due to old leaking capacitors. | * Like almost all Macs of this era, you must recap the board due to old leaking capacitors. | ||
* The LC power supplies are known to require capacitor or other repairs due to age. | * The LC power supplies are known to require capacitor or other repairs due to age. | ||
* An incompatible or faulty MC68882 co-processor will cause the system to not power on. | |||
=Troubleshooting= | =Troubleshooting/Repair= | ||
===Capacitor replacement=== | |||
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: | |||
* 5 x 47uf 16V | |||
* 5 x 10uf 16V | |||
* 1 x 100uf 6.3V | |||
=See Also= | =See Also= | ||
Revision as of 22:13, 18 September 2019
The LC III is powered by a 25MHz Motorola 68030. Apple also released the LC III+ which is essentially the same system but the board was altered to increase the clock speed to 33MHz. The LC III does not include a math co-processor but a socket is available to install a Motorola 68882.
General Information
At some point during the production run it seems that the case design was changed from the traditional LC front panel to what was used in the Macintosh LC 475.
The LC III replaces the Macintosh LC II and is the last of the Motorola 68030 based "pizza box" LCs, as the Macintosh LC 475 used the Motorola 68LC040.
Expansion
The LC III supports LC PDS expansion cards from the earlier LCs, but it also supports specific LC III PDS cards made for the larger data path of this system. The physical expansion slot is larger on the LC III to support these cards.
Notes
- Like almost all Macs of this era, you must recap the board due to old leaking capacitors.
- The LC power supplies are known to require capacitor or other repairs due to age.
- An incompatible or faulty MC68882 co-processor will cause the system to not power on.
Troubleshooting/Repair
Capacitor replacement
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:
- 5 x 47uf 16V
- 5 x 10uf 16V
- 1 x 100uf 6.3V