Apple Macintosh 128K

A rare early "M0001" Macintosh 128K — identified by the original case labelling as a very early production unit. It arrived having been donated by a university department that was clearing out its archives. The machine's last known use was in an administrative office sometime in the early 1990s.

On initial inspection, the case showed typical age-related yellowing (especially severe on the rear vent area), and the screen showed a strong vertical bright line down the centre of the display — a classic symptom of a failed horizontal deflection circuit. There was also visible corrosion at the edge of the analog board near the flyback transformer.

The 3.5" disk drive eject mechanism was completely non-functional: the disk would insert but never eject, and the drive motor was audible but produced no head movement — likely a deteriorated drive belt combined with a seized eject gear.

1. Analog Board Recap
The analog board (Apple 820-0064-A) was fully recapped. Of particular concern were the capacitors around the HOT (horizontal output transistor) and flyback section, which showed significant leakage. A total of 22 electrolytic capacitors were replaced with Nichicon rated capacitors. The corrosion was cleaned with PCB cleaning solution, and affected traces were touched up with fine solder.

2. CRT Horizontal Circuit Repair
The bright vertical line was caused by a failed horizontal deflection yoke capacitor (the 47µF/16V cap in the yoke circuit, a notorious failure point on early Macs). After replacement, the horizontal sweep was restored. The CRT was then degaussed and the geometry calibrated using the adjustment pots on the analog board: vertical size, vertical position, contrast, and horizontal frequency were all trimmed to spec.

3. Disk Drive Restoration
The Sony MFD-51W drive was disassembled. The drive belt (a 28mm flat rubber belt) had completely liquefied — a near-universal failure on these drives. A replacement belt was fitted and the eject gear mechanism freed with careful cleaning and light lubrication. The read/write head was cleaned with IPA. After reassembly, the drive reads original Mac 400K disks correctly.

4. Logic Board Inspection
The logic board showed no visible failures — no battery leakage (this early model predates the clock battery addition) and all socketed chips seated correctly. The RAM chips were tested via Mac Test (booted from floppy) and all 16 chips pass.

5. Case & CRT Cleaning
The internal CRT face was cleaned from the inside (required carefully removing the CRT from the yoke assembly) to remove dust and minor haze. The case exterior was cleaned, but not retrobrighted — this unit is a display piece and the original patina is preserved as-is.

The machine now boots cleanly from disk (Mac System 1.1 / Finder 1.1) and displays a sharp, correctly-proportioned image on the 9" Sony CRT. The famous "Happy Mac" chime sounds clearly from the speaker.

This machine is now part of the permanent workshop display collection rather than being sold. It represents an extraordinary piece of computing history — one of the first ~50,000 Macs ever manufactured — and I felt it deserved a permanent home where visitors can see it running.

Note: 128K RAM limits System compatibility to early versions (System 1.x / 2.x). For practical use, upgrading to 512K or "Fat Mac" spec is advisable, but this unit is preserved in original configuration.