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Macintosh Classic II Memory Upgrade Guide

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The Macintosh Classic II and the Macintosh Performa 200 have 2 MB of RAM soldered to the logic board and two 30-pin SIMM sockets beside it. The maximum is 10 MB.[1]

Memory rules

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  • 2 MB soldered to the logic board.[1]
  • Two 30-pin SIMM sockets on the logic board. Fill both with SIMMs of the same capacity, or leave both empty.[2]
  • Speed: Apple's Service Guide asks for 100 ns or faster; the Service Source says 120 ns or faster.[2][1] SIMMs of 100 ns or faster satisfy both.
  • Maximum 10 MB: 2 MB on board plus two 4 MB SIMMs.[2]
Macintosh Classic II RAM configurations (Apple)
Total RAM SIMM 1 SIMM 2
2 MB empty empty
4 MB 1 MB 1 MB
6 MB 2 MB 2 MB
10 MB 4 MB 4 MB

Source for the table: Apple's Service Guide, Classic II Memory Upgrade.[2]

ClassicII-memory-layout
Classic II logic board, showing the two 30-pin SIMM sockets (page from Apple's Memory Guide)

Tools

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  • Long T15 Torx driver. Two of the four case screws are deep inside the handle recess.[3]
  • Case spreader (pull-apart tool).[4]
  • CRT discharge tool and an anti-static wriststrap. See Recommended Tools.

Procedure

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The Classic II contains a CRT. Read CRT Discharge Procedure first. Apple's order is to discharge the CRT before fitting a grounding wriststrap, never the other way round.[4] Apple's Service Guide adds that on the Classic II the CRT is discharged to the ground lug, to avoid damaging the logic board.[5]

  1. Switch off and unplug the machine.
  2. Remove the four case screws and separate the rear cover from the chassis with the case spreader.[4]
  3. Discharge the CRT.
  4. Disconnect the logic board power cable, the floppy drive cable and the hard disk data cable from the logic board. Grasp the board by its corners and slide it straight up and out of the chassis.[4]
  5. Hold each SIMM by its edges with the contacts pointing down, insert it at an angle, then push back on the top corners until it clicks into place. Fit the second SIMM the same way.[2]
  6. Refit the logic board and cables. When refitting the cover, the two black case screws go in the bottom and the two silver screws in the top.[4]
  7. Check the total in About This Macintosh.

Common problems

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Symptom Likely cause Action
Sad Mac icon at startup A bad or mismatched SIMM Apple's chart: replace the bad disk first, then the SIMMs in the two logic board slots, then the logic board[6]
Sad Mac with black vertical lines and a screeching sound A bad SIMM Replace the SIMMs in the two slots, then the logic board[6]
Total lower than expected One socket empty, or two SIMMs of different sizes Fit a matched pair[2]

Sad Mac codes are decoded on Sad Mac Error Codes and with the Sad Mac Decoder.

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References

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  1. ↑ 1.0 1.1 1.2 Apple Computer, Macintosh Classic/Classic II/Performa 200 Service Source (115-page copy, File:Classic ii.performa 200.pdf), Specifications, Memory p. 2 (PDF p. 6): "Classic II/Per 200: 2 MB, expandable to 10 MB (120 ns or faster SIMMs)".
  2. ↑ 2.0 2.1 2.2 2.3 2.4 2.5 Apple Computer, Apple Service Guide for Macintosh Computers, Volume II (Apr 1992), Classic II tab, Memory Upgrade p. 12 (PDF p. 18). Hosted as File:APPLE MACINTOSH SERVICE GUIDE VOL2 1992.pdf.
  3. ↑ iFixit, "Macintosh Classic disassembly", steps 1 and 6: four Torx T15 case screws, two by the ports and two hidden in the handle. The Classic II uses the same case.
  4. ↑ 4.0 4.1 4.2 4.3 4.4 Apple, Macintosh Classic/Classic II/Performa 200 Service Source, Take Apart: Cover pp. 1–3 (PDF pp. 30–32), Logic Board pp. 12–15 (PDF pp. 41–44).
  5. ↑ Apple, Service Guide for Macintosh Computers, Volume II, Safety p. 3 (PDF p. 5).
  6. ↑ 6.0 6.1 Apple, Macintosh Classic/Classic II/Performa 200 Service Source, Troubleshooting, Symptom Charts, Miscellaneous pp. 13–14 (PDF pp. 26–27).
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