Identify your MX-5050

These documented clues can help when the rear model code is unavailable. They narrow a family; the code on the rear identification plate remains the best way to identify an exact version. For the silver-face machine's badge, record buttons and serial dating, see the first-generation guide.

One box, or two?

• Two: the transport in one, the electronics in the other. This is a Mark II feature: Otari's November 1976 sheet says "separate transport and electronics" and pictures the two units.
• Two, perhaps, on a QXD or 8SD. Their instruction manual puts each two-channel electronics unit "directly beneath the transport control panel or in a separate mounting case" — see the First generation (OIM-1004E, 1-1-(2)).
• One: read on.

Upright or desk-top?

• Stands upright, or lies flat. Otari gives the operating position as "vertical or horizontal" for the silver-face machine (spec sheet S-111) — the First generation — and in the same words for the MX-5050B (1979 B brochure) and the B-II (OS3-038, p.1-6). Otari's 1991 series data sheet, OA-321C, calls the B-III machines "Upright" (OA-321C, p.3).
• An upright four-channel BQ-II. Operated "vertically or at an angle", but sold in the MARK III series (OS3-031, section 2-4).
• A desk-top only. The MARK III/2 is "a compact, tabletop console recorder" and the III/4's operating position is "Horizontal (Tabletop type)" — the MARK III (MARK III/2 data sheet; OS3-035, PDF p.22). The 1991 table calls every MARK IV "Desk Top" (OA-321C, p.3).

Belt and flywheel, or direct drive?

• Belt and flywheel. A standard silver-face machine has an AC hysteresis-synchronous capstan motor driving a flywheel by belt — the First generation (the first-generation guide); so does the synchronous MX-5050B — the 2H, 2L and 4L (OS2-004, section 2-4).
• Direct drive. The D-suffix MX-5050B (OS2-004, section 2-6); every B-II (OS3-038, p.1-2); the MARK III/4 and the BQ-II in the MARK III series (OS3-035, PDF p.14; OS3-031, 1-1-(1)); and every B-III and MARK IV, on a brushless motor (OA-321C, pp.1 and 3).
• Not yet known. The Mark II's factory paper says DC servo capstan, not how it drives the shaft (S-114, p.2; db, January 1978, p.9).

Plate-code reference

The model code on the rear plate names the machine. Find it in the model-designation reference; the suffix letters decode as H 15 & 7½ ips, L 7½ & 3¾ ips, T output transformers, D DC servo, E DIN, ₂ separate electronics.

Have a serial number, a photo, or a correction? Get in touch.

Sources

First generation (Mini Pro)

• First-generation identification guide — the restoration machine's front, record-ready buttons and rear plate; its capstan section documents the belt and flywheel.
• Instruction manual OIM-1004E — 1-1-(2), where the QXD and 8SD electronics can sit.
• Spec sheet S-111 — the silver-face machine's operating position.

Mark II

• Mark II preliminary specification sheet S-114 — the November 1976 factory photograph and specifications for the two-channel and four-channel Mark II.
• The Rest of the Otari Line — the smaller 1979 line-up photograph labelled Mark II-2.
• db, January 1978 — p.9, Otari's line-up ad describing the separate transport and electronics and DC servo.

MX-5050B (plain B)

• MX-5050B brochure, 107-9-79 — front-panel photograph and operating position in the specifications.
• MX-5050B maintenance manual, OS2-004 — sections 2-4 and 2-6, the belt-driven and direct-drive capstans.

B-II

• B-II brochure (1983), p.2 — the period front photograph used for comparison.
• B-II instruction manual, OS3-038 — p.1-2 (direct-drive capstan), p.1-6 (operating position).

MARK III (including BQ-II)

• MARK III series brochure (1984) — colour photographs of the III/2, III/4, III/8 and upright BQ-II.
• MARK III/2 data sheet — the tabletop console recorder.
• MARK III/4 manual, OS3-035 — PDF p.14 (direct-drive capstan), p.22 (operating position).
• BQ-II manual, OS3-031 — the operating position and direct-drive capstan.

B-III (including BQIII)

• MX-5050 Series data sheet OA-321C (1991) — B-III and BQIII photographs, upright configurations and the brushless direct-drive capstan (pp.1 and 3). PDF scan.

MARK IV

• MX-5050 Series data sheet OA-321C (1991) — MARK IV photographs, desk-top configurations and the brushless direct-drive capstan (pp.1 and 3). PDF scan.