Macintosh SE Troubleshooting: Difference between revisions
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Begin troubleshooting by confirming the analog board provides correct voltages: ideally, '''+5V''' DC (within '''4.90–5.10V''') and '''+12V''' DC at the floppy or SCSI drive connectors. | Begin troubleshooting by confirming the analog board provides correct voltages: ideally, '''+5V''' DC (within '''4.90–5.10V''') and '''+12V''' DC at the floppy or SCSI drive connectors. | ||
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* Perform full capacitor replacement (recap) on the logic board | * Perform full capacitor replacement (recap) on the logic board | ||
== | == "Simasimac" – Horizontal Stripe Pattern == | ||
[[File:Simasimac issue.jpg|thumb|Macintosh Simasimac]] | [[File:Simasimac issue.jpg|thumb|Macintosh Simasimac]] | ||
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* Inspect the '''Apple Sound Chip (ASC)''' and '''RP2 filter network''' | * Inspect the '''Apple Sound Chip (ASC)''' and '''RP2 filter network''' | ||
== | == Chimes of Death and Sad Mac Codes == | ||
The '''Chimes of Death''' suggest serious logic board issues: | The '''Chimes of Death''' suggest serious logic board issues: | ||
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See [[Sad Mac Error Codes]] for full interpretation of error patterns. | See [[Sad Mac Error Codes]] for full interpretation of error patterns. | ||
== | == Video Display Issues == | ||
=== No Video but Chime Present === | === No Video but Chime Present === | ||
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* Use compatible ROM for SE (not SE/30 or IIsi) | * Use compatible ROM for SE (not SE/30 or IIsi) | ||
== | == Disk Drive and SCSI Issues == | ||
=== Frozen Mouse on Gray Screen === | === Frozen Mouse on Gray Screen === | ||
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* [[Macintosh Floppy Drive Maintenance]] | * [[Macintosh Floppy Drive Maintenance]] | ||
== | == Audio and ADB Issues == | ||
=== Audio Issues === | === Audio Issues === | ||
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* Inspect solder joints on VIA chips and ADB port | * Inspect solder joints on VIA chips and ADB port | ||
== | == Recurring Reset or Clock Failures == | ||
* Random resets = failing capacitors or shorted traces | * Random resets = failing capacitors or shorted traces | ||
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* Clean up any electrolyte residue near ASC, VIA, or Egret chips | * Clean up any electrolyte residue near ASC, VIA, or Egret chips | ||
== | == Analog Board Troubleshooting == | ||
* '''Vertical line only''' = horizontal deflection issue → reflow P1 pins, replace '''C15''' | * '''Vertical line only''' = horizontal deflection issue → reflow P1 pins, replace '''C15''' | ||
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* '''Clicking power supply''' = logic board short or bad startup circuit ('''CR2/CR3''', '''Q2''', '''R22''') | * '''Clicking power supply''' = logic board short or bad startup circuit ('''CR2/CR3''', '''Q2''', '''R22''') | ||
== | == Related Pages == | ||
* [[Macintosh SE General Maintenance]] | * [[Macintosh SE General Maintenance]] | ||
* [[Macintosh HDD Maintenance]] | * [[Macintosh HDD Maintenance]] | ||
Revision as of 08:52, 12 May 2025
Begin troubleshooting by confirming the analog board provides correct voltages: ideally, +5V DC (within 4.90–5.10V) and +12V DC at the floppy or SCSI drive connectors.
If the SE appears completely dead (no fan, CRT glow, or startup chime):
- Check analog board fuses, rectifiers (CR2, CR3), Q2 transistor, and R22 resistor
- Test voltages with a multimeter
- Disconnect any peripherals or internal cards
- Inspect logic board for corrosion or capacitor leakage
- Ensure reset and interrupt switches are not jammed
- Perform full capacitor replacement (recap) on the logic board
"Simasimac" – Horizontal Stripe Pattern
The infamous Simasimac pattern (horizontal B&W stripes, no chime) usually means failed reset circuitry or RAM issues caused by leaky capacitors.
Steps to resolve:
- Clean and reseat ROM and RAM chips
- Replace PRAM battery if below 3.0V
- Verify CPU reset and 16 MHz clock with an oscilloscope
- Check continuity around capacitors for damaged traces
- Inspect the Apple Sound Chip (ASC) and RP2 filter network
Chimes of Death and Sad Mac Codes
The Chimes of Death suggest serious logic board issues:
- Reseat and clean ROM SIMM and RAM modules
- Ensure memory banks are filled with identical SIMMs (4 per bank)
- Test RAM slots and address/data lines for continuity
- Replace faulty ICs like 74F258 multiplexers
- Severe cases may involve the VIA or ASC chips
See Sad Mac Error Codes for full interpretation of error patterns.
Video Display Issues
No Video but Chime Present
- Confirm CRT glow and brightness control
- Check for missing sync/video signals at P1 connector
- Suspect ICs like UE8 (video multiplexer)
Vertical "Jailbar" Stripes
- Caused by RAM misconfiguration
- Ensure matching SIMMs in each bank, larger ones in Bank A
Checkerboard Pattern
- Indicates ROM or early memory failure
- Clean and reseat ROM SIMM
- Use compatible ROM for SE (not SE/30 or IIsi)
Disk Drive and SCSI Issues
Frozen Mouse on Gray Screen
- Suggests SCSI controller (NCR 53C80) failure
- Disconnect internal SCSI devices to test
- Replace SCSI chip if necessary
Floppy Drive Issues
- Clean mechanical components
- Check or replace the SWIM floppy controller
- Resolder or replace nearby ICs
More on this can be found at:
Audio and ADB Issues
Audio Issues
- No chime could mean bad ASC or analog amplifier
- Check headphone jack – if it works, analog board is likely at fault
- Replace ASC if digital audio fails
ADB Issues
- No keyboard/mouse? Check and replace:
* Fuse F1 * ADB microcontroller (Egret)
- Inspect solder joints on VIA chips and ADB port
Recurring Reset or Clock Failures
- Random resets = failing capacitors or shorted traces
- Clock loss = bad 32.768 kHz crystal or dead PRAM battery
- Clean up any electrolyte residue near ASC, VIA, or Egret chips
Analog Board Troubleshooting
- Vertical line only = horizontal deflection issue → reflow P1 pins, replace C15
- Horizontal line only = vertical collapse → check TDA1170A vertical IC
- Wavy display = failing flyback transformer
- Clicking power supply = logic board short or bad startup circuit (CR2/CR3, Q2, R22)