Macintosh IIsi Troubleshooting: Difference between revisions

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See [[Macintosh IIsi Capacitor Replacement Guide]] for detailed recapping procedures.

== ⚠️ PRAM battery — remove it now ==

The Macintosh IIsi carries a 3.6 V 1/2AA lithium PRAM battery. These leak and can '''burst''', spraying corrosive electrolyte across the logic board and destroying nearby components — often while the machine simply sits in storage. '''Remove the PRAM battery from any un-serviced unit.''' If one has leaked, neutralise and clean the residue and repair corroded traces and vias before troubleshooting.<ref name="mac2_batt">[https://68kmla.org/bb/threads/warning-exploding-maxell-pram-batteries.25169/ "Warning! Exploding Maxell PRAM Batteries"], 68kMLA; and [https://macdat.net/macintosh/macii/macintosh_iicx.html MacDat — Macintosh II family]. Source for the leaking/exploding lithium PRAM battery that destroys nearby components.</ref>

== ⚠️ Surface-mount capacitor leakage ==

The Macintosh IIsi logic board uses surface-mount electrolytic capacitors that leak with age and corrode the board; '''recap and clean the logic board''' as a first step, then recap the power supply.<ref name="mac2_cap">[https://macdat.net/macintosh/macii/macintosh_iicx.html MacDat — Macintosh IIcx/II family]; and 68kMLA recap threads. Source for the Mac II-family surface-mount electrolytic logic boards that leak and corrode with age and must be recapped.</ref>

== Power supply ==

The desktop power supply uses electrolytic capacitors that fail with age. The classic symptoms are a machine that will '''rarely turn on, cannot be switched off without unplugging it, and clicks from the PSU when merely plugged in'''. Recap the power supply and confirm the +5 V and +12 V rails. (This PSU form factor is shared across the IIci, IIcx, IIvi, IIvx, Performa 600, Quadra 650 and Quadra 700.)<ref name="mac2_psu">[https://68kmla.org/bb/threads/compact-desktop-power-supply-capacitor-lists-by-make-and-model.35890/ "Compact/Desktop Power Supply Capacitor Lists (by make and model)"], 68kMLA; and [https://www.bigmessowires.com/2016/04/21/capacitor-replacement-in-a-vintage-power-supply/ "Capacitor Replacement in a Vintage Power Supply"], Big Mess o' Wires. Source for the shared desktop PSU form factor (IIci/IIcx/IIvi/IIvx/Performa 600/Quadra 650/Quadra 700), the electrolytic failure symptoms and the PSU capacitor lists.</ref>

== References ==

== Related Pages ==

@@ Line 167: / Line 167: @@
 See [[Macintosh IIsi Capacitor Replacement Guide]] for detailed recapping procedures.
+== ⚠️ PRAM battery — remove it now ==
+The Macintosh IIsi carries a 3.6&nbsp;V 1/2AA lithium PRAM battery. These leak and can '''burst''', spraying corrosive electrolyte across the logic board and destroying nearby components &mdash; often while the machine simply sits in storage. '''Remove the PRAM battery from any un-serviced unit.''' If one has leaked, neutralise and clean the residue and repair corroded traces and vias before troubleshooting.<ref name="mac2_batt">[https://68kmla.org/bb/threads/warning-exploding-maxell-pram-batteries.25169/ "Warning! Exploding Maxell PRAM Batteries"], 68kMLA; and [https://macdat.net/macintosh/macii/macintosh_iicx.html MacDat &mdash; Macintosh II family]. Source for the leaking/exploding lithium PRAM battery that destroys nearby components.</ref>
+== ⚠️ Surface-mount capacitor leakage ==
+The Macintosh IIsi logic board uses surface-mount electrolytic capacitors that leak with age and corrode the board; '''recap and clean the logic board''' as a first step, then recap the power supply.<ref name="mac2_cap">[https://macdat.net/macintosh/macii/macintosh_iicx.html MacDat &mdash; Macintosh IIcx/II family]; and 68kMLA recap threads. Source for the Mac II-family surface-mount electrolytic logic boards that leak and corrode with age and must be recapped.</ref>
+== Power supply ==
+The desktop power supply uses electrolytic capacitors that fail with age. The classic symptoms are a machine that will '''rarely turn on, cannot be switched off without unplugging it, and clicks from the PSU when merely plugged in'''. Recap the power supply and confirm the +5&nbsp;V and +12&nbsp;V rails. (This PSU form factor is shared across the IIci, IIcx, IIvi, IIvx, Performa 600, Quadra 650 and Quadra 700.)<ref name="mac2_psu">[https://68kmla.org/bb/threads/compact-desktop-power-supply-capacitor-lists-by-make-and-model.35890/ "Compact/Desktop Power Supply Capacitor Lists (by make and model)"], 68kMLA; and [https://www.bigmessowires.com/2016/04/21/capacitor-replacement-in-a-vintage-power-supply/ "Capacitor Replacement in a Vintage Power Supply"], Big Mess o' Wires. Source for the shared desktop PSU form factor (IIci/IIcx/IIvi/IIvx/Performa 600/Quadra 650/Quadra 700), the electrolytic failure symptoms and the PSU capacitor lists.</ref>
+== References ==
+<references />
 == Related Pages ==