Service training binder · Site-authored index
The Mini Pro in the Binder
The service training binder spans Otari's whole product line — duplicators, MTR studio machines, the microprocessor-era MX decks. This page is the site's index of what applies to the first-generation MX-5050 documented here. Nothing below is factory text: every entry cites its scan page and links into the digital edition — or start from the 58-page PDF.
The Mark I's hardware in the binder
| Item | Part number | In the binder |
|---|---|---|
| Pinch roller (1/4") | KP0A007 | Pinch roller cross reference, scan p. 14 |
| Pinch roller (1/2" machines) | KP0A009S (old KP-2B-A) | Pinch roller cross reference, scan p. 14 |
| Head assembly (4S) | KH-4N-A | Head guide, MX section, scan p. 10 |
| Head assembly (2SD) | KH-4C-B | Head guide, MX section, scan p. 10 |
| VU meter, no hood | ME11003 + lamp LU2049 | VU meter & lamp guide, scan p. 18 |
| VU meter, hooded | ME11004 + lamp LU2049 | VU meter & lamp guide, scan p. 18 |
| Remote control | CB-102 | Remote & auto locator list, scan p. 16 |
The KP0A007 row is one of the rows a previous owner marked with a highlighter — whoever owned this binder serviced these machines. The VU meter rows call the first generation the "OLD MX-5050 SERIES", without and with the meter hood. The prefix guide decodes the KP, ME, LU and CB prefixes.
Four first-generation machines appear in the head assembly guide's MX section, under bare model references — the 4S (assembly KH-4N-A), the DC-capstan 2SD (KH-4C-B), the quarter-inch four-channel QXD (KH-4E-B) and the half-inch eight-channel 8SD (KH-2H-B) — though the plain 2S never shows up by name. Those rows carry more weight than they look: the history page uses them to show that first-generation heads are the same Otari parts fitted to later machines, and the 8SD's KH-2H-B assembly is still the MARK III/8's seven years later. The extension-PCB list is a true gap: it begins at the BII era, so no extender board is listed for any first-generation deck.
Applies when working on the deck
The binder's training material is machine-agnostic; these are the pieces that matter when calibrating or rewiring a first-gen deck.
- Standard reproduce time constants — the Mark I plays NAB 50 + 3180 µs at 7.5 and 15 in/s; scan p. 46. The fuller playback-EQ constants table is on scan p. 38.
- Example of recommended over bias — headed MX-55N, but the per-tape-stock values (456, 406/407, SM911…) transfer; scan p. 34.
- Tape flux level — NAB and IEC operating levels in nWb/m against the VU scale; scan p. 41.
- Balanced line and XLR conventions — including the pin-2/pin-3 hot caution; scan pp. 36–37.
- Ampex 406/407 performance data — the tape stock era of the reels this project exists to play; scan p. 48.