The MX-5050 family

Two chassis lines, four transport generations, one platform. The silver-face Mini Pro is the machine this site is for; these pages are for its siblings — the machines that share its paper, its parts and its reputation problem. Their documentation is as scarce online as the Mini Pro's was, so each page says plainly what is held, what is known, and what is wanted.

Era	The capstan — what actually changes	Upright: the B line	Desk-top & wide formats: the MARK line
1974‑77	AC hysteresis-synchronous, belt-driven flywheel; DC-servo varispeed optional — but standard on the Mark II	MX-5050 — the Mark I, "Mini Pro" · silver brushed-metal face · this site's subject	Mark II-2 ¼″ 2-channel · Mark II-4 ½″ 4-channel · on sale Feb 1977
~1978	Split line: 2H/2L/4L keep the AC synchronous capstan; the D-suffix models (2HD, 2LD, 4LD…) get DC-servo direct drive	MX-5050B · darker trim	the Mark II carries on
1981‑83	DC-servo direct drive, now standard	MX-5050BII	MARK III/8 July 1981 · III/4 1982 · III/2 1983
~1990‑91	DC brushless, quartz-PLL servo, direct drive; microprocessor transport logic	MX-5050BIII	MKIV-2 / 2E ¼″ · MKIV-4 / 8 ½″

This site's subject

The Mini Pro

1974–77 · ¼″ 2- and 4-channel. Identify it, read its specs, and find every document held for it.

Thin

Mark II

from 1977 · ¼″ 2-channel (II-2) · ½″ 4-channel (II-4)

Thin

MX-5050B

c. 1978–81 · ¼″ 2-channel (2H, 2L) · ¼″ 4-channel (4L) · DC-servo D-suffix variants

Thin

MX-5050-8 / 8D

1975–81 · ½″ 8-channel

Wanted

QX / QXD / QXHD

from 1975 · ¼″ 4-channel

Reference: a page with its paper. Thin: a page with gaps. Wanted: mostly an appeal for paper.

Contribute

Every dashed card on these pages is a document this site does not hold: manuals, brochures, spec sheets, rear-plate photos. A scan of the shared Mark II / QXD / 8SD maintenance manual would document three machines at once. Contributed scans are credited on their card in the Library. Corrections to any page are welcome too.

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