Apple ProFile Troubleshooting Guide
Fault-finding for the Apple ProFile, from Apple's Level II service manual and 1983 owner's manual. Apple's procedure isolates a fault to one of four modules: the controller board, the analog board, the head disk assembly (HDA) or the power supply. Apple warns that the HDA is "a very expensive and fragile device".[1] Opening the cabinet and Apple's adjustments are on Apple ProFile General Maintenance.
First checks
[edit | edit source]- Check the interface cable and power cord. Apple's owner's manual says that loose cables cure most problems, and that rough handling in shipping can loosen a connector inside the cabinet.[2]
- Switch the ProFile on before the computer and wait for the Ready light to stay on.[2]
- A Ready light that is not steady after 3 minutes indicates a fault.[2]
The power-on scan
[edit | edit source]At every power-on the controller runs a scan that should take no longer than 90 seconds. Apple's description of a normal scan, as seen with the cover off:[1]
- The Ready light comes on for no longer than half a second, then goes off.
- After about 20 seconds the interrupter arm on the HDA moves to its track 0 position.
- The Ready light blinks as the interrupter arm steps through every track from track 0 to the park position. The arm may jump briefly to the middle of its travel, where the spares table is kept, and may pause on one track for several seconds if a sector is hard to read; both are normal.
- At the end of the scan the arm returns to the park position and stays there, and the Ready light stays on.
If the scan does not complete, Apple's No Scan flowchart (p. 1.14) takes over.[1] The owner's manual describes the same sequence from outside: light on for about 2 seconds, off for about 20, flashing for about 40.[2]
The Z8 firmware fault
[edit | edit source]Apple's first check is whether the controller has a Z8 with masked ROM. On the first boards the firmware was in a ROM piggybacked on the Z8; heat expansion made its leads lose contact intermittently, and the Z8 could then switch to write mode while seeking, destroying sector headers and data on the way. The damaged sectors were later spared, so the fault looked like failing media and HDAs were replaced for no gain. Apple's fix was a Z8 with the firmware in masked ROM.[1]
Spared sectors
[edit | edit source]Once the scan works, Apple runs its Quick Debugger, which lists the spared sectors. If there are 10 or more spared sectors or 5 or more bad blocks, Apple goes to the Diagnostic Procedure flowchart to decide whether the cause is electronic (for example the controller writing while the heads move) or the media, by reading a spared sector repeatedly and examining the analog signal on an oscilloscope.[1]
Power supply voltages
[edit | edit source]With fewer spared sectors than that, Apple's next steps are to inspect the boards for bent pins, broken leads and cracks, fit any controller and analog board upgrades, check and adjust the HDA brake and index sensor, and then measure the supply at connector P3 on the controller board.[1]
| P3 pin | Signal | Limits |
|---|---|---|
| 1 | +5 V | ±0.1 V |
| 2 | +12 V | ±1.2 V |
| 3 | POK (Power OK) | +5 V ±0.3 V |
| 4 | −12 V | ±1.2 V |
| 5 | Ground |
If a voltage is missing or out of limits, Apple's method is:[1]
- Leave each module in place but disconnect J4 (HDA to power supply), J3 (controller to power supply) and J2 (controller to analog board).
- Connect a known-good controller board to J3 and measure again. If the voltages are still wrong, replace the power supply.
- If they are now correct, reconnect one at a time J3 to the original controller, J2 (power to the analog board) and J4 to the HDA, measuring after each. The module that brings the fault back is the faulty one.
Warning from Apple: at least one module must be connected to the power supply at all times to load it.[1] The supply's own limits, from Apple's specification 062-0074, are +5 V ±2%, +12 V ±6% and −12 V ±6%.[3] For capacitor values in the supply see Apple ProFile Capacitor Replacement Guide.
Speed and index
[edit | edit source]The spindle should run at 3,600 rpm ±1%, which Apple checks as a 16.500-16.832 ms period at TP1 on the controller board with a frequency counter; the procedure is on Apple ProFile General Maintenance.[4] The motor control board holds the speed to within 1% of 3,600 rpm.[5]
Related pages
[edit | edit source]- Apple ProFile
- Apple ProFile General Maintenance
- Apple ProFile Capacitor Replacement Guide
- Apple Lisa
- Hard Drive Maintenance and Repair
References
[edit | edit source]- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 Apple Computer, ProFile Level II Service Manual ("Pro-File Phase 1 Service Manual"), 072-0116, update 1 of 12 October 1984, hosted as File:Apple ProFile Level II Service Manual 072-0116 (1984).pdf. Section 1: How to use p. 1.3; Main troubleshooting flowchart sheets 1 and 2, pp. 1.4 and 1.6 (PDF pp. 16 and 18), with notes 1.1-1.2 p. 1.5 (PDF p. 17) and the power-supply note p. 1.7 (PDF p. 19); No Scan flowchart p. 1.14; Diagnostic Procedure flowchart p. 1.18.
- ↑ 2.0 2.1 2.2 2.3 Apple Computer, ProFile Owner's Manual, 030-0604-A, 1983, hosted as File:Apple ProFile Owner's Manual (1983).pdf. Getting started p. 5 (PDF p. 10); Turning on and off p. 9 (PDF p. 14); If your drive doesn't work p. 10 (PDF p. 15).
- ↑ Apple Computer, Power Supply, ProFile, specification 062-0074-C, sheet 1, hosted as File:Apple ProFile Power Supply Specification 062-0074.pdf.
- ↑ ProFile Level II Service Manual, HDA Speed Check and Adjustment Procedure, p. 2.23 (PDF p. 83), hosted as File:Apple ProFile Level II Service Manual 072-0116 (1984).pdf.
- ↑ ProFile Owner's Manual, Chapter 3, Motor Control Card, p. 16 (PDF p. 21).