Macintosh 512Ke
The Macintosh 512Ke — "512K enhanced" — was introduced in April 1986 at US$1,999[1] as the cheap end of the range after the Macintosh Plus arrived. It is a Macintosh 512K fitted with the Plus's 128 KB ROM and its double-sided 800 KB floppy drive, which together bring HFS and the 800 KB disk format to the older case and logic board. The memory stays at 512 KB and stays soldered, and there is no SCSI port.
 | |
| Specifications | |
|---|---|
| Manufacturer | Apple Computer, Inc. |
| Type | Personal computer |
| Released | April 1986 |
| Discontinued | September 1987 |
| Intro price | US$1,999 |
| CPU | Motorola 68000 @ 7.83 MHz |
| Memory | 512 KB, soldered, not user-expandable |
| Storage | Internal double-sided 800 KB 3.5-inch floppy drive |
| Display | 9-inch monochrome CRT, 512 × 342 pixels |
| Sound | Four-voice, 8-bit D/A conversion, 22 kHz sampling |
| ROM | 128 KB |
| Ports / interface | DB-19 external floppy; DE-9 mouse; RJ-11 keyboard; 2 × serial |
| OS / Firmware | System 3.2 – System 6.0.8 |
| Predecessor | Macintosh 512K |
| Successor | Macintosh Plus |
| Model no. | M0001E |
Features
- 800 KB double-sided floppy drive — twice the capacity of the 400 KB single-sided drive in the 128K and 512K.
- 128 KB ROM — the same ROM used in the Macintosh Plus, which is what allows HFS volumes and the 800 KB format. The SCSI support in that ROM is of no use without the Plus's SCSI hardware, which this machine does not have.
- No expansion. No slots, no SIMM sockets, no SCSI connector. Third-party SCSI and memory boards existed but are logic board modifications.
- Macintosh ED — the education-channel badge applied to the same hardware.[1]
System software
Shipped with System 3.2 and supported through System 6.0.8, although 512 KB of memory makes the later systems impractical for real work.
Upgrades
Apple's own upgrade path ran the other way: a Macintosh 512K could be converted to a 512Ke with the 800 KB drive and the 128 KB ROMs, and a 512Ke could be converted to a Macintosh Plus with a Plus logic board.[2]
Maintenance
The 512Ke shares its chassis, analogue board and servicing procedures with the Macintosh 128K and Macintosh 512K. See Macintosh 128K/512K General Maintenance.
The machine contains a CRT; read CRT Discharge Procedure before opening the case. Apple's published voltage procedure for this board family — voltage test cable 077-0135 on the external floppy port, 11.90–12.75 V and 4.85–5.15 V — is written up with its warnings on Macintosh Plus General Maintenance.[3]
The PRAM cell is the same 4.5 V user-replaceable alkaline type as the 128K and 512K, in a compartment on the rear of the case.[3] Alkaline leakage is neutralised with vinegar — unlike the lithium cells in the Macintosh SE and later compacts, which need bicarbonate.
Known board-level faults
A 512K or 512Ke that resets a directly connected ImageWriter II on the printer port, or that never shows up on an AppleTalk network while otherwise behaving normally, usually has a failed 26LS30 line driver at board location B6.[2]
Related pages
References
- ↑ 1.0 1.1 apple-history.com, Macintosh 512Ke (secondary source, used for the introduction price, market dates and the Macintosh ED education badge).
- ↑ 2.0 2.1 Larry Pina, The Dead Mac Scrolls, Peachpit Press, 1992, "Early Macs" chapter, which prices the 512Ke-to-Plus upgrade and documents the board-level faults quoted here. Hosted on this wiki: File:The Dead Mac Scrolls 1992.pdf.
- ↑ 3.0 3.1 Apple Computer, Macintosh 128K/512K Service Source — Specifications and Adjustments chapters. Hosted on this wiki: File:Macintosh 128k.512k.pdf.