Service manual, re-typeset edition (v2.2)

The factory Emulator Three Technical Manual (E-mu Systems, 1988, document AG 200 Rev A) only survives as scans of the printed copy. For the service work and for Project Alan, Loon Garden produced a clean edition of it: searchable text, real tables and vector drawings. This page describes that edition.

Download the manual (PDF, v2.2, 202 pages, 51 MB)

The manual text and drawings remain © 1988 E-mu Systems, Inc. The edition is shared for preservation and for servicing existing instruments.

What the edition is

• 202 A4 pages, chapters in the order of the original table of contents: guided tours, interface specifications, synchronization, SMPTE, mechanical procedures, functional test, diagnostics and trims, Dbmon reference, theory of operation, signal names, schematics, wiring diagrams, parts list, engineering changes.
• Continuous chapters instead of the page-by-page layout, with LCD screens rendered as display panels.
• Every figure, assembly drawing and the 52 schematic sheets re-traced as vector artwork, straightened and cleaned of scan artefacts. The tracings are faithful: no line, value or label was redrawn by hand.
• Original wording kept. Only obvious typing and OCR errors are fixed; everything else that looks wrong is kept and flagged.

How it was checked

Drawings. Each traced sheet was rasterised and overlaid pixel by pixel on its scan, and every place where ink was lost, added, joined or broken was inspected. From v2.1 the tracing works from the unsmoothed scan, so broken hairlines, decimal points and halftone dots survive. On the schematic sheets no difference affecting a component, value, pin number or connection remains; only some faint 1-pixel frame and dimension lines render thinner.

Text and tables. The transcription was compared word by word with two independent OCR readings. Every technical token (value, part number, address, signal name, pin) where the readings disagreed was reviewed, and no transcription error was found. Pin-out tables and the memory map were also checked entry by entry.

Conventions

Mark	Meaning
[word]	Text cut off in the original, restored by the editor.
[…]	Sentence left unfinished in the original.
[sic: …]	Error kept as printed, with the probable correct reading.
Editor’s note	Explanation added by this edition, not part of the E-mu text.
-SIGNAL or /SIGNAL	Active-low signal (overbar on the schematics).

Notable corrections and flags

The edition lists about forty editorial points. The ones most useful to a technician:

• MIDI Song Select is printed as F4, but the binary value next to it is 11110011, i.e. F3, the correct status byte.
• Floppy controller addresses in the memory map are printed without their high byte (F50008 is meant).
• Memory map: the per-channel registers are condensed (base 3E8000, channel × 10h: current size, initial size, current address, initial address). With 1 MB SIMMs only the four pairs IC64+57, IC58+56, IC55+32, IC54+31 (-RAS0 to -RAS3) are fitted.
• Interrupt vectors and firmware locations missing from the printed map were added from the disassembly of boot v2.00 and OS v2.42.
• ADC board trimmer page is printed upside down in the scan; the RT numbers match the ADC trim procedure.
• Parts list: a capacitor on the ADC board (AG106) is probably 33 pF; the unlabelled chassis section is the rack-mount chassis; rear chassis screws are HS325 in one list and HS327 elsewhere.
• ADC trim procedure has no step 2 in the original; the Dbmon test sequence announces eight subtests but lists seven.

Versions

Version	Date	Changes
2.0	2026	First complete re-typeset edition.
2.1	October 2026	Drawings re-traced from the unsmoothed scan; pixel overlay and dual-OCR verification.
2.2	October 2026	Current edition. Memory map completed from the firmware disassembly.

Note

This page is original text. The E-mu manual itself is only available as the PDF above.