Apple Macintosh Processor Upgrade

Macintosh Processor Upgrade
Apple's drawing of the upgrade kit: board, 256K cache card, spacer, 040 heat sink, fasteners and removal tool
Manufacturer	Apple Computer
Type	PowerPC 601 processor upgrade card
Interface	68LC040 processor socket
Compatible	Macintosh Quadra 605, Macintosh LC 475, Macintosh LC 575, Macintosh LC 630, Macintosh Performa 475, Macintosh Performa 575, Macintosh Performa 630
Part number	661-0255 (service)

The Macintosh Processor Upgrade is Apple's PowerPC upgrade for Macintosh models built around the 68LC040. The board carries a PowerPC 601 and plugs into the computer's processor socket; the computer's own 68LC040 moves to a socket on the board, so the machine can be switched between the two processors from a control panel. Apple's service manuals also call it the "PowerPC Upgrade Card" and, in exploded views, the "Processor Upgrade Card". It is a different product from the Apple Power Macintosh Upgrade Card, which goes in the processor-direct slot of Quadra and Centris models.

Compatibility and specifications

Apple's Service Source for the upgrade lists these computers: the Quadra 605; the LC 475, 575 and 630; and the Performa 475/476, 575/577/578 and 630/630CD/635CD/636/638CD. Apple's technical specification pages for the LC 575, LC 580 and LC 630 also describe the configuration the card gives.

Macintosh Processor Upgrade: Apple's figures

Item	Value
Processor	PowerPC 601
Clock in the LC 575, LC 580 and LC 630	66 MHz, 64-bit data path at 33 MHz
ROM	4 MB
Cache	256K on a plug-in cache card; the Service Source gives it as upgradeable to 1 MB
System software	System 7.5 or later
Computer memory	At least 8 MB of DRAM
Operating temperature	10–40 °C

The card takes the space of the LC processor-direct slot: Apple's procedure removes any card in that slot first, and its LC 575 specification lists the LC slot as unavailable in this configuration.

Kit contents

The kit contains the upgrade board with its 256K cache card fitted, a spacer, an 040 heat sink, hook-and-loop fasteners and the manuals. The heat sink is for the LC 475, Performa 47x and Quadra 605 only, and the fasteners for the LC and Performa 500 series only. A processor removal tool is needed and is ordered as a separate service part. A late design change in the 630 Service Source says not to fit the 040 heat sink when upgrading an LC, Quadra or Performa 630.

Installation

The LC 520/550/575 and LC 630 Service Sources give the same procedure. Remove the I/O door, the logic board and any PDS card first, and observe the ESD precautions.

1. Lift the 68LC040 out of the logic board socket with the processor removal tool. Lift up on the handle; pressing down can damage parts on the logic board. Pry up each side only slightly so the pins do not bend.
2. Place the spacer on the 68LC040 with the alignment corners matched: the processor's alignment corner is missing a pin and the spacer's a hole.
3. Lay the upgrade board on a firm, even surface. Line the spacer's alignment corner up with the socket's and press the processor in with both thumbs until it snaps home. A very small gap between the chip and the spacer is normal; the larger gap below the spacer comes from the board's barrel sockets.
4. Take the 256K cache card off the upgrade board.
5. Put antistatic foam under the processor socket on the underside of the logic board. On the LC 575 the EMI clips there flex easily, and heavy pressure on them bends the board.
6. On the 500 series, stick the hook-and-loop fasteners to the logic board and move the battery to the fastener on the chip behind the ADB ports to make room for the upgrade board.
7. Match the alignment corners of the upgrade connector and the logic board socket, check the pins on every side and press the board firmly home. If it resists, check the alignment again.
8. On the LC 575, pass the battery connector through the hole in the upgrade board and reconnect it. Route the battery cable clear of the heat sink, which can melt it.
9. Refit the cache card, with its longer socket on the longer row of pins, and press it firmly on.

Apple asks for a board being returned to be put back as it was: the upgrade board off and the 68LC040 back in the logic board socket.

Troubleshooting

Apple's symptom chart for the upgrade, with the cures in Apple's order:

Macintosh Processor Upgrade symptom chart

Symptom	Cures
Computer will not start	Reseat the upgrade board. Check that at least 8 MB of RAM is fitted. Replace the upgrade board.
Program will not open or quits unexpectedly	Quit other programs or restart. Give the program more memory in its Info window. Turn on virtual memory. Turn the upgrade off in its control panel. Reinstall the system software. Fit more RAM.
Application misbehaves or gives system errors	For an older application, turn off the Modern Memory Manager in the Memory control panel and restart. Otherwise turn the upgrade off in its control panel, choose Shut Down, wait 10 seconds and switch on.
Application runs slower than before the board was fitted	If it was not written for the upgrade, turn the board off in the control panel, choose Shut Down, wait 10 seconds and switch on.
System runs out of memory with Power Macintosh applications	Turn on virtual memory, set to "the size of available built-in memory plus 1". Fit more RAM.
Board turned on in the control panel but the computer starts with it off	After turning it on, choose Shut Down, not Restart, so the computer powers off completely before starting again.
Erratic mouse tracking	Turn on virtual memory, set to "the size of available built-in memory plus 1".
Computer behaves strangely or has trouble starting	Reset PRAM with Command-Option-P-R at startup, then turn the upgrade back on and reset the date, time, monitors and file sharing.

The service part number for the card is 661-0255.

Related pages

• Apple Power Macintosh Upgrade Card
• Apple Macintosh LC 575 Logic Board Upgrade
• Macintosh Processor Upgrade Service Source
• Macintosh LC 575
• Macintosh LC 630
• Macintosh Quadra 605