Editing Macintosh IIvi Troubleshooting

This guide covers common faults with the '''Macintosh IIvi''', including startup failures, video problems, and storage errors.

== Preliminary Checks ==

Before detailed troubleshooting:

* Verify the power cable is secure
* Test with a known-good outlet
* Disconnect all external SCSI devices
* Remove any NuBus or PDS cards
* Check for visible capacitor leakage or battery corrosion

== No Power ==

<templatestyles src="Template:StyledTable/styles.css" />
{| class="wikitable styled-table" style="width:100%; text-align:center;"
|+ '''Power Issues'''
|-
! Symptom !! Possible Cause !! Action
|-
| Completely dead || Blown fuse, failed PSU, bad cord || Check outlet; test power cord; check PSU fuse
|-
| Clicking or ticking || Failed PSU capacitors || Recap power supply
|-
| Powers on briefly then dies || Overload protection, shorted component || Disconnect cards and drives; test with minimal config
|-
| Fan spins but no startup || Dead PRAM battery, failed logic board || Replace PRAM battery; check for capacitor damage
|}

== Startup Failures ==

{| class="wikitable styled-table" style="width:100%; text-align:center;"
|+ '''Startup Problems'''
|-
! Symptom !! Possible Cause !! Action
|-
| No chime, no video || Dead logic board, failed capacitors || Recap logic board; check PRAM battery
|-
| Chime but no video || VRAM issue, video connector || Reseat VRAM SIMMs; check video cable
|-
| Sad Mac error || Hardware failure || Decode error code; test RAM
|-
| Flashing question mark || No boot device || Check SCSI drive; verify termination
|-
| Chimes of death || RAM failure || Reseat or replace RAM SIMMs
|}

== Sad Mac Error Codes ==

{| class="wikitable styled-table" style="width:80%; text-align:center;"
|+ '''Common Sad Mac Codes'''
|-
! Code Range !! Meaning !! Action
|-
| 01XXXX || ROM test failure || Check for corrosion; may need logic board repair
|-
| 02XXXX – 05XXXX || RAM test failure || Try different SIMMs; clean SIMM slots
|-
| 0DXXXX || NuBus card failure || Remove all NuBus cards
|-
| 0EXXXX || SCSI controller failure || Check for capacitor damage
|-
| 0FXXXX || Data bus failure || Logic board damage
|}

See [[Sad Mac Error Codes]] for complete reference.

== Video Problems ==

{| class="wikitable styled-table" style="width:100%; text-align:center;"
|+ '''Display Issues'''
|-
! Symptom !! Possible Cause !! Action
|-
| No video after chime || VRAM failure, cable issue || Reseat VRAM; check video cable and monitor
|-
| Distorted or garbled || VRAM configuration, bad VRAM || Ensure matching VRAM SIMMs; try removing VRAM upgrade
|-
| Wrong colors || VRAM issue, video DAC || Reseat VRAM; check for capacitor damage
|-
| Flickering || Loose cable, monitor issue || Check video cable; test with different monitor
|}

== Audio Problems ==

{| class="wikitable styled-table" style="width:100%; text-align:center;"
|+ '''Sound Issues'''
|-
! Symptom !! Possible Cause !! Action
|-
| No startup chime || Audio circuit failure, capacitor damage || Recap logic board
|-
| Distorted audio || Failed capacitors || Recap logic board
|-
| No audio through jack || Jack issue, cable || Test with different cable/speakers
|}

== SCSI and Storage ==

{| class="wikitable styled-table" style="width:100%; text-align:center;"
|+ '''Drive Problems'''
|-
! Symptom !! Possible Cause !! Action
|-
| Flashing question mark || No bootable System || Check SCSI drive; verify cable; test with boot floppy
|-
| Drive not recognized || Wrong SCSI ID, termination || Verify unique SCSI IDs; check termination
|-
| System freezes during boot || SCSI bus conflict || Disconnect all SCSI; add one at a time
|-
| Floppy not reading || Dirty heads, failed drive || Clean heads; test with different disks
|}

=== SCSI Termination ===
* Internal drive should be terminated
* If using external devices, terminate only the last device
* Verify each device has a unique SCSI ID (0–6)

== Capacitor-Related Failures ==

{| class="wikitable styled-table" style="width:100%; text-align:center;"
|+ '''Capacitor Failure Symptoms'''
|-
! Symptom !! Likely Cause !! Solution
|-
| Random crashes || Failed logic board caps || Full logic board recap
|-
| Audio distortion || Caps near audio circuit || Recap logic board
|-
| No startup || Power or reset circuit caps || Recap; check traces
|-
| Intermittent operation || Multiple failing caps || Full recap
|}

See [[Macintosh IIvi Capacitor Replacement Guide]] for procedures.

== Related Pages ==
* [[Macintosh IIvi]]
* [[Macintosh IIvi General Maintenance]]
* [[Macintosh IIvi Capacitor Replacement Guide]]
* [[Sad Mac Error Codes]]

[[Category:Apple Vintage Computers]]
[[Category:Apple Troubleshooting Guides]]